WATERPROOFING ENGINEERING FOR Engineers, Architects, Builders, Roofers and Waterproofers BY JOSEPH ROSS, B.S., C.E. WATERPROOFING ENGINEER FIRST EDITION NEW YORK JOHN WILEY & SONS, INC, LONDON: CHAPMAN & HALL, LIMITED 1919 COPYRIGHT, 1919 BY JOSEPH ROSS PRESS OF BRAUNWORTH & CO. BOOK MANUFACTURERS BROOKLYN, N. Y. k t. PREFACE WATERPROOFING engineering is not taught in any college, and the writers of engineering papers descriptive of engineering works only rarely embody information on waterproofing. In general, this branch of engineering is given far too little consideration and study in the laboratory and in construction. Its importance warrants a better acquaintance with its laws than exists among those most vitally interested. To remedy this condition and seemingly to supply a real need to the profession, I commenced, early in 1914, a systematic search and diligent study of existing literature on the subject of waterproofing. The field was large but the harvest surprisingly small. Secrecy is the keynote in nearly all commercial literature on waterproofing; but with the aid of chemistry much of this was dispelled. The technical literature is often but semi- illuminating, though some excellent papers and reports have been read before various engineering societies. In fact, the impression gained from perusing the literature extant on waterproofing was, that the subject seemed to be regarded as a sort of necessary evil in engineering, to be overcome as best as the exigency of the case would permit, and if this failed to try again and again until successful. The cost of waterproofing was often the last consideration, but it invariably became the least in the mad effort to successfully waterproof the more important structures. This attitude is funda- mentally and morally wrong and economically unsound, because we may find it expedient to justify our ignorance, but never profitable. In writing this book it is believed that my extensive practical experience and experimental research work in waterproofing engi- neering has qualified me to undertake this task, the magnitude of which has not been underestimated. Much thought and labor were devoted to the task of compiling and simplifying the text so as to make it understandable by all interested in the subject of waterproofing, which interest, fortunately, is gradually increasing among engineers, architects and contractors. An effort is also made to explain past and present methods and iii iv PREFACE materials of waterproofing; investigate their efficiency; draw helpful, if not perfectly exact conclusions, and, where possible, establish standard methods and materials for general waterproofing; and lastly, to emphasize the value of careful study of the whole subject by engineers, especially those engaged in design. In the hope that it will engender new thought and investigation, and in the belief that waterproofing engineering is now coming into its own, this book is dedicated to the engineering profession. It has been found impracticable in many cases to acknowledge due indebtedness, for material used, to those writing in technical and engineering society journals on waterproofing; I herewith extend to all my grateful thanks. Most kind acknowledgment for valuable assistance and sugges- tions are due and gratefully given to Mr. Percy S. Palmer, C.E., Mr. William F. Holzschuch, C.E., Mr. Samuel G. Margies, C.E., Mr. Max Miller, C.E., and particularly to Mr. Raymond J. Reddy, who, besides contributing information gained from practical experience, has been of great assistance in the preparation of the manuscript and drawings. I also take pleasure in acknowledging my indebtedness to and esteem for Mr. George L. Lucas, General Inspector of Materials of the Public Service Commission, 1st Dist. of New York, in whose department the opportunity and material for writing this book were secured. JOSEPH Ross. NEW YORK, November, 1918. CONTENTS CHAPTER I NEED AND FUNCTION OF WATERPROOFING PAGE Introduction 1 Conditions Creating Necessity of Waterproofing 1 Waterproofing The Universal Structural Bodyguard 2 Density for Watertight Concrete 3 Source and Location of Ground Water, and Its Effect on Concrete 5 Waterproofing and Drainage as a Protection against Ground Water 5 Ineffectiveness of Weep Holes in Preventing Cracks in Masonry 6 Causes and Effects of Porosity in Concrete 7 Effect of Freezing Water on Concrete 7 Effect of Sewage' and Sea Water on Concrete 8 Destructive Effect of Electrolysis on Concrete 9 Elimination of Electrolytic Effects 10 Effect of Temperature Changes on Concrete 11 Effect of Expansion Joints in Masonry 12 Effect of Uneven Settlement on Masonry 13 Hygienic Need of Waterproofing 13 CHAPTER II SYSTEMS OF WATERPROOFING Progress of the Art of Waterproofing 17 Surface Coating System of Waterproofing: Definition, Purpose and Development 18 Methods of Applying Surface Coatings 19 Preparation of Masonry Surface Prior to Application of Coating 21 Application of Slush, Scratch and Finishing Coats 22 Materials Used for Surface Coatings 23 Application of Cement Mixtures 23 Use of Lean and Rich Mortars 25 Application of Powdered Metal 27 The Sylvester Process '. 28 Application of Paraffin 28 Application of Bituminous Compounds 29 Membrane System of Waterproofing: Definition, Purpose and Development 31 Surface Preparation Prior to Application of Membrane 33 Necessity of Continuity of Membrane 34 Protection of Membrane 35 v vi CONTENTS PAGE Methods of Applying Membrane Waterproofing 40 Making Membrance Mats 42 Connecting New and Old Membranes 42 Placing Membranes around Projections and in Vicinity of Steam Pipes ... 43 Use of Special Membranes 45 Considerations for Selecting Membrane Reinforcement 46 Storing and Unrolling Felt and Fabric 48 Precautions when Heating Coal-tar Pitch and Asphalt 49 Proper Use of Kettles and Fuel when Heating Pitch or Asphalt 50 Differentiating between Coal-tar Pitch and Asphalt in the Field 51 Coal-tar Pitch Versus Asphalt for Waterproofing 51 Mastic System of Waterproofing: Definition, Purpose and Development. . 52 Applying Mastic Waterproofing 53 Precautions when Joining New and Old Brick-in-Mastic 57 Placing Mastic around Projections and in Vicinity of Steam Pipes 57 Preparation of Wall Surfaces for Brick-in-Mastic 58 Precautions for Setting-up, Filling and Stripping Forms for Brick-in-Mastic Walls 59 Settlement and Bracing of Brick-in-Mastic Walls 61 Materials for Making Mastic Their Properties and Proportions 62 Hand Versus Machine-made Mastic 63 Brick-heating Methods 65 Weather Conditions Governing Waterproofing Operations 66 Integral System of Waterproofing: Definition, Purpose and Development 66 Limitations of the Integral System of Waterproofing 68 Integral Waterproofing Materials and Their Application 69 Use of Hydrated Lime 69 Use of Inert Fillers 70 Use of Active Fillers 72 Use of Proprietary Cements 72 Use of Integral Liquids 74 Use of Integral Pastes 75 Self-densified Concrete : Definition, Purpose and Development 76 Methods of Making Dense Concrete 77 Scientific Proportioning 78 Grade of Workmanship and Supervision Necessary for Watertight Concrete 81 Grouting Process of Waterproofing: Definition, Purpose and Development 82 Application of Grout for Waterproofing 84 Cement and Sand for Grouting 85 Equipment for Grouting Process 86 Steam Pressure Concrete Mixing and Placing Machine 89 CHAPTER III IMPERVIOUS ROOFING Impervious Roofing Defined 91 Properties and Application of Shingles 92 Wood Shingles 92 Slate Shingles 93 CONTENTS Vii PAGE Tile Shingles 95 Prepared Shingles 100 Asbestos Shingles 101 American Method of Applying Asbestos Shingles 103 Hexagonal and French Methods of Applying Asbestos Shingles 103 Tin Roofing 105 Properties and Application of Tin Roofing 105 Felt (or Composition, or Built-up) Roofing 108 Applying Felt Roofing 108 Varieties of Prepared or Ready Roofings 112 Applying Ready Roofings 114 Roof Flashings 116 Roof Gutters 118 Functional Roofings 12Q Definition; Use and Varieties of Functional Roofings 120 CHAPTER IV WATERPROOFING EXPANSION JOINTS IN MASONRY Function and Properties of Expansion Joints 124 Monolithic Construction Obviates Expansion Joints 125 Design .and Spacing of Expansion Joints 126 Joints in Brick Masonry 126 The Slip-tongue and Plane-of- Weak-Bond Joints 127 Illustrations of Expansion Joints 128 Cut-offs in Expansion Joints 134 Physical-acting Expansion Joint Fillers , 140 Chemical-acting Joint Fillers 143 CHAPTER V WATERPROOFING MATERIALS Selection and Adaptability of Materials 145 Materials for Different Systems of Waterproofing 145 Nature of Materials Acting Chemically as Waterproofing Agents 147 Nature of Materials Acting Mechanically as Waterproofing Agents 153 CHAPTER VI WATERPROOFING IMPLEMENTS AND MACHINERY Applicability of Tools and Machinery for Waterproofing 166 Varieties of Mastic Mixers 166 Varieties of Heating Kettles 170 Sundry Waterproofing Implements 176 The Cement Gun 184 The Grouting Machine 186 viii CONTENTS CHAPTER VII TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING PAGE Necessity of Testing Waterproofing Materials 188 Significance and Description of Technical Tests on Bitumens 189 Specific Gravity 190 Flash Point 191 Solubility in Carbon Bisulphide 192 Solubility in Carbon Tetrachloride 194 Solubility in Petrolic Ether 194 Penetration Test 195 Methods of Determining Melting-points of Bitumens 197 Ductility Test on Bitumen 209 Evaporation Test on Bitumen 212 Determination of Free Carbon in Coal-tar Pitch ' . . . 214 Ash Test 217 Fixed Carbon Test 217 Paraffin Test 218 Dimethyl Sulphate Test 219 Tests on Treated and Untreated Cement Mortar and Concrete 219 Standard Instructions for Permeability Tests 220 Description of Standard Apparatus 221 Method of Testing Permeability of Waterproofed Concrete 222 Results of Permeability Tests on Waterproofed Concrete 224 Results of Permeability Tests on Plain Concrete 227 Description and Results of Practical Tests 229 Test on Absorption of Concrete 229 Test on Concrete Floor Hardeners 231 Comparison of Melting-points of Bitumens 235 Effect of Heat on Various Pitches Mixed with Linseed Oil 236 Flowing and Bonding Properties of Pitch Containing Small Quantities of Asphalt or Linseed Oil 238 Effect of Asbestos Filler on the Physical Properties of Bitumen 238 Ductility of Asphalt Containing Coal-tar Pitch 240 Effect of Temperature on Penetration and Ductility of Asphalt and Coal- tar Pitch 241 Comparative Tests on Coal-tar and Asphalt Mastics 247 Volume Reduction of Asphalt Mastics 248 Mastic Bond Affected by Surface Condition of Bricks 249 Relative Compression of Plain Brick, Brick and Mortar, and Brick-in-Mastic 249 Effect of Temperature of Saturants on Waterproofing Fabrics 251 Relative Amount of Saturant and Coating Material on Treated Water- proofing Felts and Fabrics 252 Effect of Drinking Water on Waterproofing Fabrics 254 Effect of Ground Water on Waterproofing Fabrics 255 Relative Absorption and Strength of Raw and Treated Waterproofing Felts and Fabrics 256 Immutability Test on Various Waterproofing Felts and Fabrics 260 Compressibility of Treated Jute-fabric Waterproofing Membranes 260 CONTENTS ix CHAPTER VIII WATERPROOFING SPECIFICATIONS PAGE Specification Requisites 262 Specifications for Waterproofing-Materials 263 Specifications for Waterproofing Concrete and Masonry Structures 273 Specifications for Waterproofing Tunnels and Subways 280 Specifications for Waterproofing Railroad Structures. 293 Specifications for Waterproofing Concrete Floors 305 Specifications for Waterproofing Roofs 306 CHAPTER IX PRACTICAL RECIPES AND SPECIAL FORMULAS Origin and Nature of Special Formulas 313 Masonry Treatments . 314' Treatments for Tanks 317 Floor Treatments . 319 Roofings 319 Waterproof Cements 320 CHAPTER X WATERPROOFING APPLIED Examples of Surface-coating Applications 323 Examples of Membrane Applications 331 Examples of Mastic Applications 353 Examples of Integral Waterproofing Applications 356 Examples of Self-densified Concrete Applications 356 Examples of Grouting Applications 357 Examples of Special Waterproofing Applications 360 CHAPTER XI COST DATA ON MATERIALS, IMPLEMENTS, AND LABOR Planning and Estimating 368 Importance of Accurate Estimates 368 Accurate Estimates Dependent on Accurate Methods 369 Labor and Materials - 370 Waterproofing Labor, Contractors and Manufacturers Graded 370 Cost Data Tables 371 CHAPTER XII PRACTICAL TABLES Explanation of Tables 379 Thermometric Equivalents 380 Specific Gravities and Degrees, Baume, for Liquids Heavier and Lighter than Water.. 381 X CONTENTS PAGE Specific Gravity and Coefficient of Expansion-of Various Materials 387 Weight and Thickness of Burlap, Felt, and Cotton Fabric Membranes with Coal-tar Pitch Binder 388 Thickness of Waterproofing Materials Required for Different W 7 ater Pressures 389 Volumes and Weights of Ingredients Used in Brick-in- (Asphalt) Mastic Waterproofing 390 Pressure Exerted by Water Beneath Floors and against Walls 392 Approximate W 7 eights and Thicknesses of Various Sheet Metals for Roof, Gutters and Flashings 393 Weights of Roof Coverings 395 Square Feet Covered by 1000 Wooden Shingles 396 Number of Slates and Pounds of Nails Required for Roofing 97 Size, Length, Gauge and Weight of Roofing Nails 397 APPENDIX I Explanation of Mechanical Analysis for Grading Concrete Aggregates 399 APPENDIX II Concrete in Sea Water 403 APPENDIX III Report on Waterproofing American Society for Testing Materials 408 APPENDIX IV Glossary of Terms Used in the Waterproofing Industry 413 APPENDIX V References 423 INDEX. . 428 WATERPROOFING ENGINEERING CHAPTER I NEED AND FUNCTION OF WATERPROOFING INTRODUCTION THE art of waterproofing, while having passed its infancy, is not yet in its adult stage of development. That it has developed from a crude understanding and practice is evident from the fact that the ancient Romans would waterproof their structures by building foundation walls so thick that water could not possibly percolate through them. Searching through both ancient and modern annals for a his- tory of the subject, we are consistently confronted by the scarcity of reliable literature on waterproofing; but it is quite well ascer- tained that the early Egyptians used asphalt * to waterproof the foundations of the pyramids, that they waterproofed the ground floors of some houses by internal and external applications of bitu- minous material, and used it also in the construction of cisterns, silos, and other works where waterproofing was necessary: that the Romans were among the first to apply successfully the early prin- ciples of waterproofing and were the first successful manufacturers of hydraulic cement. This cement was a natural cement similar to our present day puzzolan cement. Of course, waterproofing engineering as practiced by both the Egyptians and Romans must be taken in a restricted sense, for the art, as now developed and as we comprehend it to-day, was quite unknown then. Conditions Creating Necessity of Water roofing. It has been quite definitelv proven that water is practically a universal solvent; i.e., given time and water, especially sub-surface water, very few things will resist the deteriorating effect of the latter. At * For earliest history of asphalt, see: " Manufacture of Varnishes and Kindred Industries " by Livache and Mclntosh, Vol. 2, p. 3D. * " *- ." ENGINEERING certain distances below ground surface, varying both seasonally and locally, water is nearly (within several feet) at the same level (called ground-water level) throughout the year. All engineering structures, of course, have their foundations in earth or rock (which is the same thing so far as water pressure is concerned) and may be partly or entirely submerged by ground water; consequently they are subject to considerable water pressure and to the disintegrating influences of the acids or alkalies usually present in ground water. It is also evident that due to uneven settlement and continual variations of temperature, cracks may develop in superstructural and subsurface masonry, foundation walls, etc., through which water will seep regardless of how minute these cracks may be; hence waterproofing in some form becomes essential to the life and sta- bility of the structure. What this form of waterproofing should be is a problem not susceptible to precise mathematical solution, but by a careful study of conditions and with the help of past and present experience, and a knowledge of the chemical and physical properties of waterproofing materials, a form or method can be devised suitable for any special condition. Therefore, a knowledge of all manner of waterproofing systems and the properties of suitable materials becomes indispensable, at least to the engineer and architect, who usually specify how and what should be used under given conditions or for particular structures. Waterproofing The Universal Structural Bodyguard. Our era has rightly been designated the " Concrete Age." In fact, the growth of our civilization might be measured by the quantity produc- tion of cement, and the commercial progress of a community might be measured by the number and size of the concrete structures within its boundaries. In the not distant past, most solid struc- tures were composed of ordinary brick or stone masonry, and to-day not a few are similarly constructed, but these are rapidly being super- seded by concrete and steel. Even for dwellings concrete is becoming more adaptable and is being used more every day, and the prediction is made that the future will see a predominance of concrete buildings of all varieties. But co-ordinately with the use of concrete, or nearly so, is the provision of a " body guard " in the form of waterproofing. For, as iron and steel must be protected from corrosion, so must concrete be protected from disintegration, but unlike the former, concrete must also be made impermeable. Water, by its capacity of alternate freezing and thawing, reacting upon concrete as ordinarily made, with its inherent porosity, wherein water may lodge and exert its NEED AND FUNCTION OF WATERPROOFING 3 expansive or disintegrating forces, is the bane of such structures. On the other hand, water pressure is an added bane of subsurface structures. All of these causes and their effects preclude the possi- bility of making a permanently element-resisting structure without some form of protection. Waterproofing affords this protection. Efficient waterproofing is therefore rightly co-ordinate with concrete, the universal structural material, and the materials used to accom- plish this should therefore be classed as structural materials. Water- proofing not only protects but prolongs the life of any structure to which it has been properly applied. Proper waterproofing materials intelligently and adequately applied is the keynote of success in making all engineering structures watertight. But even appropriate materials unsystematically applied, or vice versa, will not produce a waterproof medium. This emphasizes the necessity of knowing all the related factors in waterproofing a structure as well as in designing it. Density for Watertight Concrete. In the making of concrete it is attempted to duplicate natural stone, in form, design and color, but especially in density. The density of average concrete is more nearly equal to that of the lighter stones (see Table I), though in practice the effort is universal to make it approach that of the heavier ones, which effort has the desirable effect of reducing its porosity. To accomplish this, engineers often and rightly resort to scientific proportioning of the aggregates, increased time of mixing, careful tamping, spading and closer supervision of construction, or again, by incorporating certain water-repellent or void-filling ingredients in mass concrete or in the mortar used for laying up the stone masonry. Where these precautions are impossible or inadequate, the structure may be placed in or surrounded with an impervious bituminous sheet-layer or membrane, forming an external water- proofing medium. From Table I it is evident that not only concrete but all kinds of stone are more or less porous. Hence this property, being inherent in all stones, must not be overlooked in construction work where it may cause damage. But this is especially true of concrete, because, as is obvious from the table, it is very difficult to make ordinary concrete denser than average limestone, and consequently, its porosity being always present, is more menacing to the integrity of any concrete structure. Ordinary concrete will absorb water more readily than is generally supposed. The presence of alkaline, such as magnesium or sodium sulphate, or of acid in ground water, tends to attack the cement in 4 WATERPROOFING ENGINEERING some manner not yet definitely known, and is one of the chief causes for the disintegration of concrete. This is especially true of the action of sea water on concrete. Other causes tending to disintegrate, or in some manner to disrupt concrete, are electrolysis, temperature changes and uneven settlement. A brief review will be made of each of these causes and their effects. TABLE I. AVERAGE WEIGHTS, SPECIFIC GRAVITIES, AND AB- SORPTION OF VARIOUS STONES AND CONCRETES STONE Kind of Stone. Weight, Lb. per Cu. Ft. Specific Gravity. Water Absorbed,* Lb. per Cu. Ft. Trap 180 2 92 Max. Min. 1 03 23 Marble 170 2 72 1 04 10 Slate . . 168 2 70 2 10 05 Granite 168 2 70 2 77 04 Limestone 162 2 60 6 62 02 Conglomerate 162 2 60 3 71 60 Sandstone 150 2 40 11 60 02 Brick 125 1.85 18 . 75 Gravel 100 2 65 Cinders 95 1 50 CONCRETE Kind of Aggregate. Weight, Lb. per Cu. Ft. Specific Gravity. Water Absorbed, Lb per Cu. Ft.* t Trap 155 2 48 3.13 Conglomerate 150 2 40 Gravel. 150 2.40 3.66 Limestone 148 2.34 3.47 Marble 144 2 30 2 48 Sandstone 143 2 29 Cinders 112 1 79 9 61 * For exact method of determining absorption of water per cubic foot of rock, see American Society of Civil Engineers Transactions, Vol. 82, p. 1437 (1918). t The figures in the last column were estimated from tests made on 6-inch cubes of 1 : 2 : 4 concrete. NEED AND FUNCTION OF WATERPROOFING 5 SOURCE AND LOCATION OF GROUND WATER AND ITS EFFECT ON CONCRETE Since water is the all-important cause creating the necessity for waterproofing, we will consider briefly its source and general loca- tion in the ground. Ground water is that part of rain, hail or snow that has percolated through and accumulated in the ground as water, either in soil or in rock, usually in consequence of an underlying impervious stratum which materially retards or totally prevents its further percolation downward. The upper surface of ground water is called the water table, or the ground-water level. The depth of ground-water level below the earth's surface varies with the locality, topography and character of the earth's material.* Ground-water level has nothing to do with mean high water, though in some localities they are at the same elevation; the latter surface, however, is usually lower. Proper drainage will, of course, lower ground-water level, and this is often resorted to in order to obviate the need of more extensive waterproofing. But as the limit of this level is mean high-water level, its successful possibilities are not unlimited. So far as water- proofing is concerned, therefore, the two water levels require equal consideration, because one or the other, or both, are always operative. A clause in the specifications for waterproofing the new subways in New York reads: " waterproofing cf the structure will be limited to the roof and to those surfaces near ground water, or mean high water, if ground-water level is found for any reason to be below mean high water." Flood water is less difficult to control than either sea or ground water, and only affects certain localities at certain times, often due to accident. Its effects are readily overcome by proper drainage, damming or simple waterproofing methods. Waterproofing and Drainage as a Protection against Ground Water. The most general effect of ground water on engineering works is to necessitate these works being constructed with special waterproofing considerations. The earth below ground-water level remains wet constantly, often subjecting an underground structure to a large hydrostatic head. It is this head of water which requires careful attention and design to make it effective. And what can- not be accomplished by design -alone can be accomplished by inclu- ding a system of waterproofing to prevent the percolation of water through the more or less porous concrete, or through slight cracks that may develop in it. * Turneaure and Russell, " Public Water Supply." 6 WATERPROOFING ENGINEERING An underground system of drainage is often included even where a complete system of waterproofing is called for and provided, as in the above cited subway specification, to wit: "Every part of the railroad must, so far as possible, be so arranged that any water finding access thereto will be led away automatically to the city sewers. Where the railroad is on an inclined gradient, and is con- structed in dry, porous soil, the floor of the railroad may be depended on to act as a conduit. At the bottom of the inclined gradient connection must be made with a sewer or with subdrains lying beneath the railroad and draining into the sewers. " Along such parts of the work where the soil is not porous, or where the floor of the railroad cannot, in the judgment of the engineer, be used as a conduit there shall be laid, beneath the rail level and on a continuous descending gradient, drain pipes of vitrified tile. Each drain shall be laid in the concrete or directly in the soil with tight or open joints, as directed, and in such manner and in such position as, in the opinion of the engineer, local circumstances require." Ineffectiveness of Weep Holes in Preventing Cracks in Masonry. Concrete retaining walls and abutments, but more especially the former, are, as a rule, provided with weep holes to take care of the water at their backings. The practice adhered to is to let one weep hole 3 or 4 inches in diameter suffice for every 3 or 4 yards of wall front. But experience has demonstrated that such weep holes do not always suffice to protect a wall against water pressure (in so far as it affects percolation), still less against deteriorating agencies in the water, and least of all do they prevent surface disfiguration due to efflorescence. Neither do weep holes prevent subsequent and uneven settlement with consequent cracking of the masonry. The reason is quite obvious; for weep holes too often and too easily become clogged, and are in consequence unable to carry off the storm water rapidly, which is their main function, consequently the water accumulates in the backfill and backs up behind the wall, causing, with the aid of head and frost, the damages referred to above. While waterproofing would not overcome all of these defects, it would undoubtedly eliminate to a marked degree their effects. In fact, the tendency in present-day construction is to eliminate weep holes and substitute a type of waterproofing meeting the purpose and need of the structure. Thus it is seen that ground water is the elemental cause against which concrete structures must be protected by the application of some waterproofing material or drainage system, or both. NEED AND FUNCTION OF WATERPROOFING CAUSES AND EFFECTS OF POROSITY IN CONCRETE Cement mortar and concrete, even when made under laboratory conditions, are far from being dense enough to completely pre- vent the percolation (independent of absorption) of water through them if time is reckoned as a factor. The volume of total voids in mortars averages about 26 per cent, and in concrete, of pro- portions commonly employed in practice, the voids range from 13 to 17 per cent. That this is a common as well as a serious condition follows from the fact that many laboratory tests show that 70 to 80 per cent of the tempering water evaporates, leaving behind it the cells that it formerly occupied, and as these cells are more or less connected, a system of ducts through the entire structure is established. This cellular condition creates a natural capillary passageway for water to enter and be absorbed in the mass. But the permeability of mortar or concrete is practically independent of that form of porosity wherein the voids form an unconnected system , but the freezing effect is quite different, and is referred to below. At this point it is probably well to remind the reader not to confound porosity with either permeability or absorption, for con- crete may be porous and yet absorb little water, and it may be absorptive, and yet not permeable. Porosity of concrete may be defined as the net-work of uncon- nected voids or honeycombing of its mass by the entrained air and water. Absorption of concrete is the property of drawing in or engrossing water into its pores or voids by capillary action or otherwise. Permeability (or percolation) of concrete may be defined as that quality, due to cracks or connected voids, which permits the flow of a liquid through it. Effect of Freezing Water on Concrete. All three states, that is porosity, permeability and absorption, are allied, and each one in some way is detrimental to concrete, for, whether water is entrained in the mass * or flows through it, or is absorbed by the concrete, when it freezes some form of damage is done. There are but few bonds strong enough to resist the expansive force of freezing water. It increases its bulk approximately 10 per cent, and the consequent expansive force is probably more than 10,000 pounds per square inch. A section of concrete 100 feet long, under 100 deg. Fahr. (55.5 deg. Cent.) change in temperature, will contract or expand T % 6 ^ of an * See striking example in Engineering News, Vol. 77, No. 9, p. 356. 8 WATERPROOFING ENGINEERING inch. This change is infinitesimal in comparison to the volumetric change in freezing water; hence the need for eliminating the porosity of concrete and also preventing the percolation of water through it. For evidence of the effect of the expansive force of freezing water, one need but observe the physical condition of natural stones exposed to the elements for a more or less protracted period of time. Even mountains, with their proverbial strength, are crippled by this agency. A very striking example of the effect of this tremendous mechanical force is seen in the crumbling of the exposed portions of the rocky Palisades on the New Jersey shore of the Hudson River. Effect of Sewage and Sea Water on Concrete.* That the dura- bility of concrete is materially impaired by its porosity is strikingly illustrated by the easy prey it falls to the action of alkali waters, sewage and sea water. The alkalies contained or formed by or in these waters, which are most active in causing disintegration of concrete, especially when allowed to penetrate into the interior of the mass, are the sulphates of sodium, magnesium, and calcium. Disintegration of concrete in sewers and sewage disposal works, whether due to the use of poor materials, poor workmanship, or lean mixtures, each of which tends to decrease the density of concrete, has been found to take place above the normal surface of the liquid contained. This action probably results from the fact that quanti- ties of hydrogen sulphide are evolved from the sewage. This sul- phide is produced in two ways: (a) By the bacterial decomposition of sulphur-containing proteins and related compounds, and (6) the reduction of sulphates which are contained in unusual amounts in some water supplies. Of the two, the second seems to be more important. The hydrogen sulphide which escapes as gas from the sewage is partially dissolved in the moisture on the under side of the roof and concrete walls. Here it is oxidized to sulphuric acid partly by atmospheric oxidation and partly by bacterial action. The sulphuric acid acts upon the calcium compounds in the concrete, forming calcium sulphate, thus breaking down the concrete. Where the effect of sea water on concrete has been other than mechanical, it is probable that disintegration is caused by the sub- stitution of magnesium oxide (MgO) from the sea water in the place of the calcium oxide (CaO) of the cement, as well as to the decrease in the proportion of silica and the increase in sulphuric anhydride (SOs). Interesting examples of these processes will be found in Engineering and Contracting, Vol. 57, No. 26, p. 580. The United States Bureau of Standards, after some extensive tests on the " action * American Railway Engineering Association, Vol. 14, p. 834. NEED AND FUNCTION OF WATERPROOFING of the salts in alkali water and sea water on cements," described in Technologic Paper No. 12 of the Bureau, remarks as follows: " The cause of the disintegration of cement structures is not certain, though it is almost universally believed that it is the reaction of sulphate of magnesia of the sea water with the lime and the alumina of the cement, resulting in the formation of hydrated magnesia and calcium sulpho-aluminate, which crystallizes with a large number of molecules of water. Other constituents of sea water, especially sodium chloride and magnesium chloride, have also been noticed to attack the silicates of the cement and produce rapid disintegration." To safeguard concrete structures against the destructive action of the above agents, it is necessary to make dense, impermeable concrete by the use of a well-graded aggregate, moderately rich mixture, proper consistency and good workmanship, and allowing the concrete to harden under favorable conditions before being exposed; or, where practicable, by applying a surface mortar coat from 1 to 2 inches thick. Both of these methods are included in distinct systems of waterproofing, which are explained in Chapter II. In Appendix II will be found more explanatory information on this interesting phenomenon. For experimental confirmation the reader is referred to the above Technologic Paper. DESTRUCTIVE EFFECT OF ELECTROLYSIS ON CONCRETE In the principle of electrolysis we have a very formidable agent at work against the integrity of concrete structures; one that requires careful study and attention in structural design and during construction. Its effect is mechanical and, though not widespread, is as disastrous as the freezing of water in concrete. The passage of an electric current through reinforced concrete causes, amongst other effects, oxidation of the iron rein- forcement. The oxides formed occupy 2.2 times as great a volume as the original iron and the pressure resulting from this increase of volume is very great. That it is possible to damage re- inforced concrete structures by stray currents from electric railways, power-houses, and general ground connections is an established fact.* Electric currents passing from the reinforcing material into the concrete for electrolytic action takes place only where the current leaves the conductor cause corrosion of the reinforcement and cracking of the surrounding concrete more or less seriously, but always sufficiently to permit the percolation of water through it, which further aids electrolysis; this, in turn, * Technologic Paper No. 18 of the Bureau of Standards, U. S. A. 10 WATERPROOFING ENGINEERING creates more cracks, thus permitting more water to enter and attack the reinforcement, whence the action is further enlarged until there arises serious danger that rupture may ensue.* Elimination of Electrolytic Effects. Partial elimination of elec- trolysis is possible by the selection of courses of masonry or con- crete of a high specific resistance and their careful distribution about the structure. As an illustration: If blocks of granite are inter- posed between the footings of a building and the soil, the tendency of the building to pick up stray currents is materially reduced because of the high electrical resistance of the granite. It may be impractic- able to take these precautions, but it is nearly always possible to surround the footings with a waterproofing membrane which will accomplish the desired end. See Fig. 1. Various proportioned concrete aggregates offer greater or less resistance to electrolysis with a showing in favor of what would ordinarily be called a poor concrete. Table II f shows the specific resistance of concrete made of Old Dominion cement, river sand and crushed trap. The specific resist- ance of concrete will, of course, vary greatly with the aggregate, method of making, etc., and the values given below are indicative only of the order of magnitude of the specific resistance that may be expected. TABLE II. ELECTRICAL RESISTANCE OF MORTAR AND CONCRETE Proportion of Mortar. Resistance in Ohms cm. 3 Proportion of Concrete. Resistance in Ohms cm. 3 Neat cement 3500 1 :2! :4 8000 1 :2 2300 1:3 : 5 8200 1 :4 2100 1:4:7 9900 In general, complete protection from electrolytic effects is not practically possible by any other means than efficient waterproofing. What form of waterproofing should be used for this, purpose depends on local conditions and the type of structure, but invariably that system which is of a membraneous nature will be most efficient. Precautionary measures against electrolysis must be taken both in the city and in the country, but perhaps more so in the country because electrical feeders are usually much better protected in cities, where laws are enacted for this purpose. * Engineering News, Vol. 66, June 8, August 3 and 17, 1911; Vol. 68, July 12, December 19, 1912. t Technologic Paper No. 18 of the Bureau of Standards, U. S. A. NEED AND FUNCTION OF WATERPROOFING 11 EFFECT OF TEMPERATURE CHANGES ON CONCRETE A fourth disrupting force, and one not easily overcome, is change of atmospheric temperature, to which influence can be ascribed many concrete failures. Additional steel embedded near Waterproofing Membrane Grillage Foundation C.I. Manhole Cover. 8 Brick- Waterproofing Membrane- 4 "Brick Protection- Hollow Tile Protection FIG. 1. Methods of Waterproofing around Column Bases and Footings to Prevent Electrolysis. the surface of the concrete is one of the means employed to combat this force. The effect of the temperature change, however, is never wholly lost, especially, though rarely, where concrete is depended upon to take tensile stress. Just to illustrate: Assuming 12 WATERPROOFING ENGINEERING the coefficient of expansion of concrete as .0000055 per deg. Fahr., and its modulus of elasticity as 2,000,000 pounds per square inch, then the stress due to temperature is 11 pounds per square inch per degree change of temperature, or, for 60 deg. Fahr. it is 660 pounds per square inch, which is double the ultimate unit tensile stress for concrete. A temperature difference between summer and winter of twice 60 deg. Fahr. is not uncommon in certain parts of the United States.* Fortunately, in this country, tensile strength of concrete is neglected. It must not be supposed, however, that steel rein- forcement, however efficiently placed, does more than diminish the size and distribute the cracks which are caused by temperature changes. But this result is sufficient to materially increase the impermeability of the structure. Effect cf Expansion Joints in Masonry. In steel, a change of temperature of 1 deg. Fahr. causes a stress of about 200 pounds per square inch if resisted. In concrete a change of 18 deg. Fahr. causes an equal stress if likewise resisted; that is, if expansion joints are not provided to take care of the expansion and contraction, the resulting stresses may cause cracks in the structure, with the usual result cf disfigurement due to efflorescence and damage due to seepage. But, on the other hand, these very expansion joints create one of the most urgent needs for waterproofing a concrete, or for that matter, any form of masonry structure. Expansion and contraction in a structure and their resulting stresses are due to changes in atmospheric temperature or change in temperature of the concrete while it is setting and hardening. This latter temperature change may be as high as 150 deg. Fahr., depending on the thickness of the masonry, f With steel rein- forcement to take care of stresses resulting from temperature change, the cracks are kept small, but not entirely prevented. The expansion joints necessary to relieve the atmospheric Jbemperature- change-stresses require special study. Their form and location in a structure not only have a great bearing on the stresses set up in it but also on their effectiveness. While expansion joints tend to relieve the effects of these stresses, they are not always effective in preventing hair cracks or cracks at angles in the structure, or leakage through the joints themselves as commonly constructed. Hence the need of an efficient type of waterproofing, in conjunction with well-designed expansion joints, > which together will most effectively overcome these defects. * American Civil Engineers' Pocket Book, 2d Edition, p. 1255. t Taylor and Thompson, "Concrete, Plain and Reinforced," 2d Edition, p. 285. NEED AND FUNCTION OF WATERPROOFING 13 EFFECT OF UNEVEN SETTLEMENT ON MACONRY A fifth important destroying agency to consider in concrete con- struction is uneven settlement. An inequality of bearing power will cause uneven settlement in a structure. Only the most careful de- signer can minimize and perhaps eliminate settlement, which some- times causes unsightly cracks, and, of course, reduces the imperme- ability of the structure. Retaining walls are particularly subject to stresses of this character. Bridge abutments and building foun- dations sometimes suffer a good deal from this cause. When to this is added the vibration in each, due to traffic or the operation of machinery, the injuries are enhanced in a manner that invites further damage when water enters the cracks. Where masonry walls support backfill behind them and tracks above them, settlement may occur due to pounding of trains on the tracks. Or, if drainage behind the walls is, or becomes, inade- quate for any unforeseen reason (due to clogging of weep holes, for instance), the earth, underneath the foundation may be undermined, causing more or less settlement with consequent cracking and the percolation of water. Concrete reservoirs often develop cracks from this cause, and in spite of their eventual silting-up often con- tinue to be troublesome until properly waterproofed. In fact, it most generally happens that settlement cracks are too large to be closed up by silting, or there may be no silt to depend on, as when building in rocky strata. But even where silt is abundant and is depended upon to close up any cracks, it always takes time, invariably defaces the structure, and the cracks may reopen by further settlement. Consequently, nothing remains to be done but to waterproof the structure, in a manner that will minimize or vitiate the effects of this agent. Hygienic Need of Waterproofing. The above considerations undoubtedly establish the fact that the ill effects of the inherent porosity of concrete and the perviousness of general masonry should be eliminated as far as possible as a matter of economy and safety. And, incidentally with the exclusion or repulsion of water (which action depends on the system of waterproofing employed) from a concrete structure, that is, with a dampproof and waterproof condition of a structure, follow other results and benefits that have both an aesthetic and hygienic effect which can ill afford to be over- looked. Concrete construction which proceeds with the idea of permanency should embody the co-ordinate functions of damp- proofness and waterproofness and uniform surfaces, free from 14 WATERPROOFING ENGINEERING I bC .S NEED AND FUNCTION OF WATERPROOFING 15 unsightly blotches and discoloration by efflorescence. (See Fig. 2.) The latter defect in concrete and brick masonry is mainly due to the absorption of atmospheric moisture, which dissolves the salts of soda, potash, magnesia, etc., present in the cement and, on evaporating, deposits them on the surface. But in many instances rain or ground water from behind walls or other structures percolates through the mortar or expansion joints, day's-work planes, cracks, or through the very body of the masonry, carrying with it also various oxides which leave rusty looking streaks or white and yellow patches on the face of the masonry that often makes an eyesore of an othei- FIG. 3. Evidence of Exudation of Lime Salts through Wall Unprotected by Waterproofing or Dampproofing. wise beautiful engineering structure. (See Fig. 3.) This condition is true of masonry both above and below ground, although in the latter case it is usually neglected. Where only this condition is to be prevented, the incorporation of a bona-fide integral compound is the most efficient means of accomplishing the desired end. Where, however, cracks are inevitable, only a membraneous system of waterproofing can. overcome this defect. In building construction, the absorption and retention of moisture in walls above ground, and moisture and water in cellar and founda- tion walls and floors below ground, cause dampness which is harm- 16 WATERPROOFING ENGINEERING ful to health. Hence dampproofing, particularly in exposed build- ings, assumes grave importance, and further emphasizes the n3ed of waterproofing, because this always acts as an effective dampproofing; that is, any structure that has been waterproofed has necessarily been dampproofed. There are conditions, however, where damp- proofing alone is necessary or possible, as for instance, exposed walls of buildings. These are usually and successfully coated with a bitu- minous compound or covered with a thin (J inch to J inch) layer of plaster or cement mortar. Sometimes a waterproofed cement mortar coat is applied an inch or less in thickness for this purpose, and if the work is carefully done so that no separating plane is left or peeling follows, proves an efficient dampproofing medium. From the foregoing it may be concluded that waterproofing requires as careful consideration in engineering work as fireproofing does in building work. With so many deleterious agents constantly at work, not only on concrete but on all masonry, the imperative need of protecting all manner of structures against them, or against their effects, becomes apparent. The form of this protection is known by the broad name of waterproofing, and the art of applying it as waterproofing engineering. To dampproof is to make a struc- ture impervious to moisture. To waterproof is to render a structure impervious to moisture and water. To accomplish this is to preserve and lengthen the life of a structure, and this in turn tends towards economy, which is an equally important consideration to the archi- tect or engineer in design and construction as to the builder or owner of a structure. CHAPTER II SYSTEMS OF WATERPROOFING Progress of the Art of Waterproofing. The progress that the art of waterproofing has made since it began to receive serious consideration Is quite notable. It is difficult to affix any definite date to the adop- tion of scientific waterproofing, but even as late as 1870 waterproofing engineering, in the broad sense we are now considering it, was more speculative than experimental. About this time the " Sylvester Process " of waterproofing (originated in England) came into vogur among American engineers, and while it still is sometimes employed, it has, in the main, been superseded by better methods and materials. Not that asphalt 'was unused prior to this date for waterproofing purposes, but there seems to have been no certainty of results con- nected with its use. Since this period and up to comparatively recent times there were developed four distinct systems of waterproofing, namely, " Mem- brane," " Mastic/ 7 " Surface Coating," and " Integral." In the last decade, a fifth system one that will often obviate the need of any of the first four has received wide experimentation with very good and consistent results. This system is applicable only to concrete structures and is designated " Self-densified Concrete." Another recent system of waterproofing is known as the " Grouting Process," which is especially applicable to subsurface structures such as tunnels and cutoff walls either in rock or earth. Both of these systems will be considered in due order. The modern systems of waterproofing then, if arranged in the order of their development, appear to be as follows: (1) " Surface coating." (4) " Integral." f (2) "Membrane."* (5) " Self-densified concrete." (3) "Mastic." (6) " Grouting process." * Mr. E. W. DeKnight claims to have introduced this term in 1902; but this term as applied to waterproofing has only been used extensively in the last decade t This term as applied to waterproofing was used as far back as 1875 but not extensively until the last decade. 17 18 WATERPROOFING ENGINEERING SURFACE COATING SYSTEM OF WATERPROOFING Definition, Purpose and Development. The surface coating system of waterproofing refers to the application of: (1) In imper- vious coating of plastic or liquid bituminous materials; (2) various liquid hydrocarbons, and chemical salt solutions forming, usually, water-insoluble compounds; (3) a wash or plaster coat of neat cement or cement mortar, the former varying in thickness from -2 inch to -2 inch, used principally on brick walls, and the latter from \ inch to 2 inches; both applied either to an interior or exterior surface of concrete or other masonry. The cement mortar coating, again, may be composed of: (a) cement, sand and water mixed in any efficient proportion that will produce a dense and impervious coating; (6) cement, sand, water and a pow- der, paste or liquid waterproofing compound (usually of a proprietary nature) which is mixed in specified proportions for the purpose of producing similar or more impervious coatings. The surface coating system of waterproofing is adapted to water- proof structures either during construction or after erection. It is applicable either to the external or internal surfaces of the structure, depending on the physical condition of the surface to receive the waterproof coating, the water pressure behind the surface, the kind of material used and the thickness of the coating to be applied. This method is comparatively cheap and has a wide application in spite of the few materials (other than proprietary ones) adapted for such coatings. Amongst the oldest preserving processes in construction work are plastering and painting. Since paint forms an impervious coat- ing easily and cheaply applied, it was utilized not only for decorative, but also for dampproofing purposes. It was a matter of general knowledge that linseed oil paints and varnishes, besides serving other obvious purposes, were also a dampproofing medium; that lime plaster and cement mortar, especially the latter, applied in comparatively thin coats, performed the same function. Hence the next step in the development of this system of waterproofing was to apply a coat of bituminous paint or a mortar coat, thick and dense enough for each material to act also as waterproofing. Eventually there came into use proprietary waterproofing compounds employed directly as surface coatings or incorporated in the plaster or mortar coat to increase its imperviousness. The surface coating system of waterproofing is in common prac- tice to-day, especially the mortar surface coat, because with it the SYSTEMS OF WATERPROOFING 19 engineer encounters the least difficulties. The invention of the " cement gun " has made this possible more so than any improvement in the grading or proportioning of the ingredients for producing impervious mortar. The history of this invention is rather inter- esting. About 1895 Mr. C. F. Akeley, a taxidermist of Chicago, invented the cement gun for the special purpose of coating the framework of a dilapitated house with morta^ to save it from de- struction. This proved so successful that he coated other frame buildings by the same means. In 1911 engineers in the United States service in the Philippines experimented with a similar machine until they perfected it, and then used it quite extensively. Since then the cement gun has come in modified and improved form, into quite general use. FIG. 4. Applying Plaster Coat Over Bituminous Dampproofing Coat. Methods of Applying Surface Coatings. There are three com- mon methods of applying impervious coatings: (1) by brush, (2) by trowel, (3) by machine. All liquid compounds are applied with a brush (see Fig. 4) , or paint-spraying machine, both processes being done in the same manner that paints are applied. When thus applied, the compound either forms a film on the surface or penetrates the surface of the mortar or concrete, and by capillary action is drawn further in to a depth varying between J and J inch (see Fig. 5), depending on the solvent, porosity of the surface and density of the mortar or concrete. As a plaster coat, the given waterproofing material is applied with a trowel by hand (see Fig. 4) . In this proc- ess pressure and uniform motion are essential, but most essential is the continuity of the coating. As a mortar coat it may be applied 20 WATERPROOFING ENGINEERING either with a trowel or with the cement gun. When the plaster, neat cement, or mortar surface coatings are applied with a trowel, as on the back of a retaining wall, the outside of a brick sewer or manhole, the inner face of a tunnel or swimming pool, they should be finished off to bear a smooth or granolithic face. The granolithic surface on these coatings, produced only by careful troweling, materially increases their imperviousness. The coatings should not be made too thin, as peeling, blistering, and cracking inevitably follow, especially if used where they are subject to atmospheric changes. When mortar is applied with the cement gun, the coat can be made a very efficient waterproofing medium, provided the materials are properly used and proportioned. In no case should a leaner mixture than 1 : 3 be used and the best results will follow the use of FIG. 5. Ideal Penetration of Surface Coating. a clean, somewhat moist and coarse, but graded sand in the mixture. In operating the cement gun (see Fig. 6) the dry materials are forced through a hose by means of compressed air, hydrated at the nozzle, and applied with any desired velocity. This velocity of approach of the mixture produces a considerable rebound of the sand, which is wasted; this leaves, however, the adhering mixture richer in cement. The combination of cement, sand and water which pro- duces the plastic material, takes place in transit, i.e., the hydra tion takes place immediately before and during the placement; the chemical combination or initial set of the cement takes place in its final resting place. If the surface is floated immediately after placing, a smoother finish is obtained. Troweling, however, will not always increase the imperviousness of the mortar, and may even offset the good effects of floating, hence it should be practiced with great care or not at all. The technique of cement-gun applications requires thorough familiarity with the machine and proportioning of aggregate SYSTEMS OF WATERPROOFING 21 before any important waterproofing work can be prosecuted success- fully. Chapter VI contains a more detailed description of the modern cement gun. Preparation of Masonry Surface Prior to Application of Coating. Before applying any of the dampproof or waterproof coatings, all masonry surfaces should be prepared by chipping off all skins of dried or hardened cement or other material, so that practically an entirely new surface is produced. It is best to do this not more than a few days prior to the application of the coatings. Chipping FIG. 6. Applying Mortar Coat with Cement Gun. (Operated with Power from Automobile Engine.) the surfaces will be facilitated and a much better bond secured by a previous application of muriatic acid of about 1 to 10 solution, the strength of the solution depending on the age of the structure to be treated. The acid should remain on the surface until it has exhausted itself. This will require about fifteen minutes. Then a second coat, and if necessary a third coat of acid solution should follow the first and be brushed in with a stiff wire brush. When sufficient aggregate has been exposed and the entire surface cleaned, all traces of the acid must be removed. This is best accomplished by a rigid application of water from a hose immediately after the 22 WATERPROOFING ENGINEERING acid treatment has reached a satisfactory stage. This slushing, which should be done with perfectly clean water, should continue until all the salts (formed by the chemical action of the acid on the cement) are removed and the surface is free from acid. All holes, large or small, should be plastered up independently of the surface coating unless the coating is a waterproofed mortar. Application of Slush, Scratch, and Finishing Coats. If the wall or other surface is not washed with acid it should at least be chipped and brushed, and just before the mortar coating is to be applied, the surface should be thoroughly drenched and soaked to its full absorbing capacity. Then, before the walls or other surfaces show marked signs of drying, a " slush coating " should be applied over the entire surface. To prepare this slush coat some of the mixed ready-for-use coating material may be thinned with water to the consistency of cream. It is then applied with a stiff brush, with a scouring effect, care being exercised to fully cover the inner surfaces of all crevices and holes. Before the slush coating has dried, the first application of the regularly mixed coating material should be applied as a scratch coat, from J to J inch thick, and pressure brought on the trowel to push the coating on, and so obtain a uniformly thick layer, well bonded. The best practice is to trowel the scratch coat to a fairly good sur- face, and then to scratch criss-cross over the entire surface before it hardens. This insures a better bond for the finishing coat. Upon the scratch coat, and before its final setting, a finishing coat of sufficient thickness to obtain the required thickness of mortar coat should then be applied. If this required thickness is more than 1J inches, the thickness of the scratch coat should be increased accordingly. The finishing coat, too, should be pushed on hard and uniformly troweled and floated to a true surface, free from pits, pin holes, sagging cracks, projections or other defects. The floating of the finished surface is best done from the bottom of the wall up. These instructions are applicable whether the coating contains a waterproofing compound or not. In general, also, the surface of masonry to be waterproofed by the surface coating system of waterproofing should be cleared of any interference from timbers and temporary struts, because the presence of such false timbering interferes with the proper and con- tinuous application of the waterproofing. If such false timbering is not readily removable, then the locations of struts and posts, etc., resting on or against the surface to be waterproofed, require very careful workmanship and close inspection to insure the proper and SYSTEMS OF WATERPROOFING 23 Complete waterproofing of holes left by removal or shifting of such false work on the completion of the construction in hand. This is especially true when such timbering is situated in poorly illumined and cramped areas. A method of overcoming these difficulties is explained in the article on the membrane system of waterproofing. Other means of procuring a continuous surface so as to avoid leaving unwaterproofed areas will suggest themselves as the occasion arises; the important point to remember is that every temporarily unsur- faced spot constitutes a weakness in the waterproofing system. Materials Used for Surface Coatings. The materials generally used for surface coatings are: (1) neat cement, cement mortar, and proprietary cements, i.e., ordinary cements containing void- filling or water repelling substances; (2) finely powdered metals, as, for instance, powdered pig iron; (3) mixtures of soap and alum; (4) paraffin, either in liquid form, or in solid form, but melted, or in solution with petroleum oil or coal-tar naphtha; (5) patented bitu- minous products, i.e., mixtures of asphalt, linseed oil or wood oil and resin with some form of inert filler, as powdered or shredded asbestos; (6) proprietary liquid hydrocarbons, i.e., solutions of paraffin in benzine or benzol, or emulsions of petroleum oil and fat oil. Some of these can be applied to a wet or submerged surface (varieties of the patented bituminous products), but a dry surface is always preferable. The general properties of some of these materials are treated in Chapter V. Practical but simple illustrations of the manner and method by which coatings are applied are shown in Figs. 4, 7, 8. Fig. 4 shows a brick wall below ground surface, coated with a liquid bituminous paint which in turn is surfaced with a treated (i.e., waterproofed) mortar. This process is most effective as a dampproofing rather than as a waterproofing. Fig. 7 shows a culvert arch waterproofed with a plastic, bituminous compound. Fig. 8 is a cross-section of a swimming pool waterproofed with a cement mortar coating. To this mortar was added a definite amount of a proprietary powdered metallic compound to increase its imperviousness. Application of Cement Mixtures. In applying either neat cement or cement mortar, the engineer is not handicapped by lack of knowl- edge of the materials or results. The required information is readily obtainable with considerable certainty. However, when patented cements are used this is not true to the same degree. Experiments and experience have proven the waterproofing qualities of the former, but the same cannot be said of the latter. In fact, in many instances ordinary well-made and applied mortar will be more effective. 24 WATERPROOFING ENGINEERING The United States Army engineers recommend the use of sand- cement for mortar coatings.* This cement is sometimes substituted for the natural, but Portland cement has been found to be the best to use for waterproofing purposes. For coating sea walls and other marine constructions, puzzolan or slag cement mortar is well adapted. For coating exterior concrete wall surfaces and interior surfaces of cisterns or tanks, and especially any masonry below ground-water level, Portland cement mortar in proportions 1 : 1 or 1 : 1J will create watertightness. The mortar should preferably be applied against the surface which is to come in contact with the water. FIG. 7. Applying Bituminous Coat with Brush to Arch of Culvert. But where a good hold can be secured for the mortar and if made thicker than J of an inch, it may be applied to the other side. In Table XXXII are given suitable thicknesses applicable to varying heads of water. Where imperviousness is desired both ways, both sides should, of course, be coated. Increased watertightness will be secured under all conditions, whether the mortar coat be applied by hand or machine, by troweling the surface to a granolithic finish. However, this granolithic finish must be produced with the greatest care, otherwise it will vitiate its purpose. * Taylor and Thompson, " Concrete, Plain and Reinforced," 2d Edition. SYSTEMS OF WATERPROOFING 25 Use of Lean and Rich Mortars. The use of lean or rich mortar is mainly dependent on the purpose each is to be put to. Mortar contracts on drying and expands on wetting, hence cracking invari- ably results. This is greatly reduced by reducing the proportion of cement, which alone is affected and causes the cracks. In stucco work or on other superstructural applications the leaner mortar is most advisable. The sand should be graded so that the pro- portion of medium-sized grains is small, and the coarse and fine grains are about equally mixed. Experience shows, for instance, that a plain 1 : 3 stucco, prop- erly applied, remains free from cracks, but is rather porous. A 1 : 2 stucco, however, while less porous, is subject to considerable crack- ing, unless well protected during the setting period. But such pro- tection (i.e., protection against freezing, or exposure to the sun and quick drying out) besides being a good deal neglected, is often impossible. 12 Concrete FIG. 8. Swimming Pool Waterproofed with Waterproof Mortar Coat. Hence it resolves itself to a question of how to make stucco mortar lean enough to avoid cracks, yet dense enough to be damp- proof. This difficulty is often overcome by the use of a suitable integral waterproofing compound, or a surface coating material which evaporates slowly and leaves the surface pores filled. Since the strength of mortar* here is of least consideration, and absolute impermeability of the mortar of secondary consideration, (i.e., the mortar for stucco work need but be made dampproof) these waterproofing materials find a very good field of usefulness. But the indiscriminate use of such compounds as, for instance, soap and alum washes, caustic potash, stearin and resin compounds, or chloride of lime and other metallic salts, or, for that matter, any of the many waterproofing or dampproofing compounds, without test or careful investigation is unwarranted. The architect who specifies any of these compounds without investigating or experi- menting (and all too many do so) to ascertain their value for this 26 WATERPROOFING ENGINEERING particular purpose is wasting his clients' money and hazarding his own reputation. The many worthless and the few worth while compounds on the market make it imperative to search most con- scientiously for a material that will not wash out after a few rain storms; that will not discolor or disintegrate, or induce disintegra- tion; that will prevent hair checks and remain cementitious while creating imperviousness in the stucco, and that will not induce peeling or blistering of the stucco. Service and practical tests are the best, and in fact, the only means for determining the effectiveness of any of these materials. In connection with the use of a large proportion of cement in mortar or excess cement in concrete, it must be borne in mind that the practice is wrought with many dangers for vitiating its ostensible purpose, i.e., increasing the density of mortar or concrete. For underground construction this practice is entirely warranted and efficacious, but for superstructural work of any sort this practice is successful only on the performance of the work with the most pains- taking precautionary measures for curing, drying, and seasoning the structures. Only a few of the many patented cements and bituminous paints on the market for waterproofing by the surface coating system possess the requisite properties for efficient usage. In general, these properties are : (a) That absolute dampproof ness or waterproof ness be effected by their use; (6) reasonable cheapness; (c) applicability; (d) durability. Experience and experiment have shown that only a very few of these special dampproofing and waterproofing com- pounds possess the same effectiveness as a moderately thick coating of neat cement or cement mortar, the latter of a maximum thickness of about 2 inches for the most adverse conditions. Cement mortar, as ordinarily mixed, can be made practically impervious by the addition of alum and potash soap. One per cent by weight of powdered alum added to the dry cement and sand and thoroughly mixed, and about 1 per cent of any potash soap (ordinary soft soap) dissolved in the water used in mixing the mortar will make it remarkably impermeable, but the results are not lasting. A dry clay mixed with cement in equal proportions and applied as a coat- ing is also effective as a waterproofing agent, provided any form of cracking is prevented. A surface coat of cement mortar of a thickness and proportion best judged from requirements at hand, is sometimes used for creating a dry surface upon which to apply a different system of waterproofing. SYSTEMS OF WATERPROOFING 27 The impermeability of plain cement mortar is well shown in Table III, which is adapted to our purpose from the United^ States Bureau of Standards, Technologic Paper No. 3. TABLE III. PERMEABILITY OF MORTAR OF QUAKING CONSISTENCY Proportion by Volume of Portland Cement to Meramic River Sand. Ago in Weeks when Tested. Cubic Millimeters of Water Passed per Minute per Square Centimeter of Surface Subjected to 1.4 km. (3.1 Ib.) Hydrostatic Pressure.* Thickness of Test Pieces in Inches. 1 2 3 1 :2 4 8 26 1 :4 4 1.0 1.0 8 26 1 :6 4 31.2 24.0 17.0 8 .8 2.0 5.0 26 . 19 .8 .5 1 :8 4 149.0 324.0 749.0 8 90.5 132.0 126.0 26 9.0 9.0 43.0 * Average value of three test pieces tested for six hours. Application of Powdered Metal. The waterproofing effective- ness of powdered metal, such as powdered pig iron or other iron oxide depends upon the barricading effect of its increased bulk due to corrosion while it is held in suspension in the gaging water, which, of course, permeates the mass. When mixed with the cement, which is the most usual way, the moist particles of iron oxidize and expand, thus filling the voids in the concrete mass; or, when applied to the surface of concrete, either as a slush coat or thin mortar coat, its action results in the production of a hard, dense, and impervious finish. The corrosion is often assisted by the addition, in very small quantities, of some oxidizing agent such as sal-ammoniac or sulphur. This same mixture is often used, under various trade names, as a concrete floor hardener. In fact, powdered metal finds its greatest usefulness in this field. When so used it should be floated on the surface and then finished off with a trowel. Success in the Use of this material necessitates the employment of very careful and skillful 28 WATERPROOFING ENGINEERING labor. Quantities and rules for applying powdered metal are usually issued by the manufacturers of these materials, and should be care- fully followed. The Sylvester Process. The use of soap and alum solutions for coating a masonry surface is known as the Sylvester Process of damp- proofing and waterproofing. It is applicable alike to concrete and other masonry. It does not, however, form a permanent water- proofing, and is not much used at the present time. In using these materials the following precautions must be observed: (a) Each should be perfectly dissolved before being applied. (6) The masonry surface should be dry and clean before application, (c) The air temperature at the time of application should be between 50 and 60 deg. Fahr. (10 and 15.5 deg. Cent.), (d) The soap solution should be boiling hot and applied first, using a flat brush for this purpose. The alum solution is then brushed on at a temperature between 60 and 70 deg. Fahr. (15.5 and 21 deg. Cent.), thoroughly covering the first coat. An interval of one day should elapse between the appli- cation of each set of coats. The number of coats is dependent on local conditions, including water pressure and exposure to the elements. The proportion of soap and alum giving the best results is f pound of castile soap to 1 gallon of hot water; J pound of common alum to 4 gallons of lukewarm water. The action is chemical. The two materials combine to form a stearate of aluminum, which fills the voids in the concrete and is insoluble in water. A solution con- sisting of 1 pound of concentrated lye, 5 pounds of alum, and 2 gallons of water, applied while the concrete is green and until it lathers freely, has been successfully used. A cheap and effective substitute is a mixture of. 1 part of aluminum sulphate and 3 parts of hard soap, by weight. This may also be used as an integral compound, in proportions determined by experiment, for mass mortar or concrete. Application of Paraffin. The application of paraffin is universal and adapted to all classes of masonry above ground. If applied cold it is specially treated, e.g., it is boiled to rid it of water, the presence of which renders it difficult to apply, and dissolved in a highly volatile compound. Being an almost colorless, translucent liquid, it does not change the color of the surface to which it is applied. It is easily applied with a stiff flat brush, and the best results are obtained by thoroughly rubbing it into the surface, using three coats if the surface is rough. If the surface is clean and smooth, two coats are sufficient, because the solvent has a high penetrating SYSTEMS OF WATERPROOFING 29 capacity, by which function it leaves the pores filled with paraffin after the volatile matter has evaporated. Most paraffin compounds are prepared for use by the manufacturer, who usually issues direc- tions for their application, but ordinary commercial products may be used. In general, however, the following precautions should be observed: (1) The surface treated should be made smooth and dry, the first by chipping all projections and rubbing with a stiff wire brush if necessary, the second by doing the work after a dry period. (2) No fire should be near the material when applied, because the volatile solvent is very combustible. If the paraffin is to be applied hot, it is merely melted and thoroughly rubbed into the surface, which has been previously pre- pared and warmed, to be waterproofed. The latter is most economic- ally done with improvised salamanders, using charcoal as fuel. If dissolved in the proportion of one-third paraffin and two-thirds kerosene, it remains soft longer and penetrates the stone further. Paraffin is the very best waterproofing material for exposed work of all kinds, but needs to be applied by men experienced in this work. With a sufficient penetration, durability and effectiveness is assured because of the natural inertness of the paraffin. Application of Bituminous Compounds. There are many bitumi- nous paints, pastes, and enamels offered by manufacturers for use in the surface-coating system of waterproofing. Compounds of this nature are also used for dampproofing. When used for this purpose, the film or coat is usually applied somewhat thinner than for water- proofing. For the latter purpose, the film or coat does not exceed J inch, except when the material is a bituminous mastic, in which case it is applied in thicker form. If employed as dampproofing for exposed walls of buildings or other superstructures, these bituminous compounds are usually applied on the interior or between wall sur- faces. As waterproofing, these compounds are applied either on the exterior or interior surfaces of underground works, depending on conditions. In structures already erected some of these compounds are well adapted to remedy leaky conditions because they can be applied on the inside and sometimes to a moist surface. This obviates the expense of excavating around the foundation. Allowing bituminous waterproofing materials to remain in direct contact with earth or other backfill, i. e., unprotected, is poor practice because the acids or alkalies present in the backfill will eventually destroy such materials. Bituminous coatings are sometimes applied to the inner surface of foundation walls and tunnels even where a water pressure exists, but they are not dependable to withstand 30 WATERPROOFING ENGINEERING this condition unless backed up with an inch or two, or more, of cement mortar or concrete, and the work done with care. A priming coat should always be used before applying liquid bituminous surface coatings to waterproof a structure, and in this connection field engineers and inspectors will do well to guard against the following practices: (1) Failure to apply a continuous priming coat; (2) the use of a viscous material as a priming coat. On cer- tain construction work, especially municipal work, it is often to the advantage of the manufacturer or his agent to supply material of the same consistency for the priming coat as for the other coats, because very much more of it is required for the first than for the succeeding coats on account of the usual roughness of the surface. The waste of material, however, is the least objectionable in this case. The serious nature of such practice lies in the failure to utilize the priming coat for what it was intended to accomplish, namely, to enter the surface pores of the concrete or other masonry, to find every little depression or small hole and coat it, and to assure the adhesion of the coats which follow. These objects are not well accomplished by using a viscous material for a priming coat. The right consistency of a priming coat is one as liquid as water or milk, in which state it can penetrate deeper below the surface. The composition of most surface coating compounds is kept secret by the manufacturer, and the only real safeguard one has in purchasing them discriminately is to observe the results on structures already waterproofed with any of these products. In general, the following precautions should be observed when buying and applying such materials: (1) Chemical test on a representative sample of the material should show (a) preponderance of bitumen, (6) resistance to acids and alkalies, (c) strong adhesion to concrete or other ma- sonry, (d) toughness at low temperatures. (2) Results of tests on representative specimen should be checked with material as received and then applied according to the manufacturer's directions. (3) The surface to be waterproofed must be made clean and dry, applying not less than two coats; the first coat, usually a primer (that is, the same material, or ordinary asphalt or tar, thinned to a more liquid consistency) is allowed to become dry or nearly so, before the second is applied. (4) Great care is required (a) to obtain a continuous film of coating, (6) to fill all corners, recesses and depressions, (c) to leave the final surface roughened, yet coated, if a plaster or mortar coat is to be applied directly on the film, (d) not to injure the film in applying these coats, and (e) not to expose the applied material unduly. SYSTEMS OF WATERPROOFING 31 Straight-run coal-tar products are often and successfully used in the surface-coating system of waterproofing. For example, in protecting abutments and retaining walls from disintegration due to their natural permeability, various dampproofing bitumens are successfully and cheaply made and applied, of common creosote oil and coal-tar pitch. The creosote oil is applied first and penetrates the wall to a degree depending on its quality and the density of the masonry, and this is followed by at least two moppings of the coal- tar pitch. In some instances where the concrete is very porous, a third and fourth mopping may be required in order that the entire surface may be well covered. Dull spots on the surface are evi- dence that the pitch has only penetrated into the pores of the con- crete but the outer surface is not completely coated. A mixture of coal-tar and powdered slate of the consistency of molasses is often used for similar purposes. Occasionally, a 2 or 3-ply felt- and pitch- membrane is applied to such structures. Instead of the tar products, refined asphalts of good grade may be also used. Where a first or priming coat is required, and it is practically always advisable to apply one, this usually consists of asphalt diluted in naphtha or gasolene. Of course, both the pitch and asphalt must be of a consistency and melting-point to withstand the local climate or special condition of the work. Either of these materials will be benefited by a protective coat of some form, especi- ally when this waterproofing is in the form of a felt or fabric mem- brane. A bituminous paste composed of chinawood oil, asbestos and pine tar is well adapted for such and similar purposes, but its consistency and application must be carefully watched. Coating the surface with boiled linseed oil until the oil ceases to be absorbed is another method that has been used with success. In Chapter IX are to be found various formulae of compounds usable for damp- proofing and waterproofing purposes. MEMBRANE SYSTEM OF WATERPROOFING Definition, Purpose and Development. The membrane system of waterproofing refers to : (1) a built-up, elastic, continuous bitumi- nous blanket or membrane composed of one or more layers of water- proofing felt or fabric cemented together with asphalt or coal-tar pitch, and which more or less completely surrounds the structure waterproofed; (2) metal linings, which usually also constitute an integral part of the structure, as in steel-plate or ring tunnel 32 WATERPROOFING ENGINEERING tubes* wherein the metal lining is protected within and without by masonry. (3) Any method or material which permits the more or less complete enveloping of a structure to prevent the passage of water through its exterior parts, but which is itself not in direct contact with the water, that is, which is itself protected by some other cover- ing. Such protective covering may be of concrete, vitrified hollow tile, or brick in cement mortar and sometimes a layer of mastic. The purpose of the membrane system of waterproofing is princi- pally to waterproof structures in course of erection, particularly those below ground surface, such as subways, tunnels and building founda- tions; but it applies equally well to retaining walls, arches, reser- voirs, etc. It is not so well adapted to the waterproofing of structures already erected or to remedy leaky conditions developing subsequent to erection, owing to the fact that the membrane must be applied to the outside of the structure, thereby usually necessitating con- siderable excavation. In the very earliest times, asphalt was used simply as a surface coating, that is, to serve as dampproofing. In this condition it was not well adapted to resist water pressure, even when placed between two masonry surfaces. To overcome this defect, fibrous paper was introduced between these surfaces, with a coating of bitumen on either side. For greater water pressures, the number of plies of paper was increased, each being coated with bitumen as applied. Paper was gradually superseded by waterproofing felt; this was largely composed of rag and wool, or pulp. The wool variety of felt has had until comparatively recent times a very extensive use, but because of the unreliable quality of wool purchasable now, and to an extent, its high cost, rag felt and pulp felt are now more com- monly used. These felts are now in sharp competition with cotton and jute fabric. Commercially, refined asphalt and coal-tar pitch have been used for a long time in connection with the treatment of paper, felt, jute and cotton fabric, and also as a binder for forming waterproofing membranes of these materials. Now there is some- times incorporated in these bitumens mineral fillers, such as shredded asbestos for instance, for the purpose of increasing their plas- ticity and substantiality Applying the felt or fabric membrane to a structure calls for certain precautions which can ill afford to be neglected. These pre- * Metal linings or castings may be used anywhere, but especially where great stresses are anticipated or where it is practically impossible to apply the ordinary membrane. This type of construction, however, requires special design for each case, SYSTEMS OF WATERPROOFING 33 cautions are embodied in three fundamental requirements to be care- jfully observed in order to insure good waterproofing by the membrane system. These are (1) surface preparation; (2) continuity of membrane; (3) protection of membrane. Surface Preparation Prior to Application of Membrane. It is impossible to make a bituminous sheet adhere properly to a wet or rough masonry surface, but it is advisable to make it adhere to what- ever surface it is applied. The surface to be waterproofed should, therefore, be prepared by chipping all projections and smoothing off with mortar and trowel all depressions; cleaned by sweeping or scraping off all foreign matter of whatever nature ; dried (when water- proofing must proceed during rainy weather, or before the concrete has completely dried after setting), by heating the surface, if not large, with a gasoline torch, by burning gasoline on the surface to be waterproofed, or by employing salamanders; or again, by pro- viding a temporary drainage system that will keep the surface dry during the application of the waterproofing. If these measures are impracticable or insufficient, then one or two plies of felt, with the first laid dry, that is, without a bituminous binder on the under side, and nailed to or against the wet surface, if necessary, will create a dry area for the application of the waterproofing proper. Where it is difficult or impossible to apply this dry-ply, as on arches of tunnels, a thin sheet metal lining nailed to the masonry, or a cold application of asphalt dissolved in naphtha, or a reasonably thick plaster coat of neat cement or mortar, provides a dry surface on which to start waterproofing. Of course the concrete in all cases must be thoroughly set before any waterproofing is applied. As an illustration of how such problems are met in practice, may be cited the following instance. In building the east face of the south Manhattan shafts of the Pennsylvania Railroad tunnels,* preparations were made to place the felt and coal-tar pitch waterproofing in the ordinary way, but it soon became necessary to drain away water that was running down over the face of the wall from the exposed rock above. To accom- plish this a drain was constructed on the face of the wall near its top. This consisted of a strip of tin set in a ridge of plaster of Paris stuck on the face of the wall. The drain had a slight grade down- ward. It answered the purpose very well, allowing the wall to dry out below the drain. This type of drain was found useful at many points, because it could be applied quickly and at small cost. * Transactions, American Society Civil Engineers, Vol. 69, p. 80. 34 WATERPROOFING ENGINEERING Necessity of Continuity of Membrane. Continuity of the mem- brane is more important than the preparation of the surface to be waterproofed, for it is not always necessary to make the membrane adhere to a surface as long as the sharp projections have been removed and a reasonably smooth surface obtained; but lack of continuity creates a condition directly opposed to the purpose of waterproofing; for water will find the break, large or small, percolate through it, and be a source of annoyance at first and danger at last. The continuity of a waterproofing membrane may best be secured by breaking joints systematically and leaving sufficient lap to form a good connection with the adjoining section. In applying the bituminous binder it is necessary to avoid blowholes, " dry spots," and other common defects. But these dangers are partly obviated by the very method of building up a membrane (see Fig. 14). In using either felt, fabric or cotton drill for this purpose, such defects will be greatly reduced by lightly pressing into the hot binder, which, incidentally, prevents " kinks " and also insures better adhesion between successive plies as well as to the original surface. Where the fabric is of the open mesh variety, the formation of air pockets between successive plies is automatically prevented, and pressing it into the binder will insure the filling up of all the interstices of the fabric. Where a connection is made between a wall and roof of a structure, the lap should be about 1 foot wide. The successive plies of the membranous mat forming the lap on the wall should be interwoven with those of the roof mat and stuck fast against the side of the wall with binder. In joining the floor membrane with that on the wall, the latter should be interwoven as shown in Fig. 9A, with the lap ends of the floor membrane turned up an amount depending upon local conditions, but never less than 6 inches. One of the most important matters in regard to the continuity of the waterproofing membrane, and one requiring careful attention, is the joining of new work to old. The old waterproofed surfaces, or the old laps, should be cleaned of all foreign matter, and, where necessary, softened by heating, as explained in " Surface Prepara- tion." Such laps should receive a coat of bituminous material before the new strips of fabric are applied and pressed down as previously explained. Where possible, a mesh joint should be made of the laps of the old and new fabric as the plies are laid up. After long exposure of a portion of a membrane or its end lap, as on an uncompleted portion of work, the felt or fabric may have deteriorated or have been torn off. It is absolutely necessary to SYSTEMS OF WATERPROOFING 35 provide sufficient lap width to properly join the old and new water- proofing; hence the safest expedient is to recoat the membrane with a thick binder film in the first instance, and to cut back at least 6 inches of the concrete or other masonry to secure sufficient lap in the second instance. :*' *SSSi^-te? 4-f^\ f^ssKxy^Sfxn: DURING PROCESS OF CONSTRUCTION A WALL ALREADY IN PLACE B FIG. 9. Methods of Applying Membrane Waterproofing to Walls and Footings. Protection of Membrane. The third fundamental requirement of the membrane system of waterproofing is the protection of the membrane during construction, but more particularly after. During construction the waterproofing membrane may be injured by the workmen carelessly throwing about iron tools which sometimes puncture the membrane. The placing of temporary struts on the membrane may have a similar effect. Dumping of bricks and the unrestricted hauling of material, or walking on the membrane is particularly harmful to its continuity. A waterproofing membrane 36 WATERPROOFING ENGINEERING appHed to vertical masonry tends to sag and produce a rippled surface, especially in warm weather or when a particularly soft binder is used. In fact, no bituminous membrane, no matter how well applied or what binder is used, will stand up completely intact without support of some sort under such conditions. After construction the waterproofing membrane may be injured by the impact of stones in the backfilling material, or by the large aggregate in the protective concrete if this is deposited from an undue height; or by bulging and running of the bituminous material due to heat, or cracking and chipping due to cold. Where there is any considerable hydrostatic pressure behind the membrane it may be perforated in a weak spot, or where a slight bulge or " ripple " has occurred in it, the added weight of the water on the bulge may drag the membrane down. A serious menace to bituminous membranes surrounding under- ground structures arises from leaks in gas mains and sewers in city streets. All gas mains collect a kind of a pungent oil called gas-drip, which frequently comes out of leaky joints in the mains, saturating the ground over considerable areas. This oil will, in a comparatively short time destroy a portion of a waterproofing membrane by dis- solving the bituminous binder, and, where felt is used, turn it into a soft, mushy and worthless material. Then again the membrane may be attacked by lubricating oil and other solvents from leaks in underground pipes or from machinery, as for example, where switch pits for surface railroads are in close proximity to the waterproofing of the structure. Nearly all sewers, besides carrying sewage (which is sometimes acidulated and sometimes alkaline), carry steam and other gases, and where leaks occur, which happen quite often, the ground becomes saturated over a considerable area. The deleterious effect on the membrane in this instance is quite the same as in the case of gas-drip or oil, but not so marked. Again, if a membrane is injured in any way, then the worst and perhaps the only serious drawback of the membrane system of waterproofing is encountered. The leak in the membrane is usually inaccessible from the outside without costly excavation, and cannot be gotten at on the inside except by removing considerable masonry. But what is still worse, it is almost impossible to tell where to begin excavation or tearing out the inner masonry, due to the fact that water is likely to travel a long way between the membrane and the wall so that the location of the leak or leaks on the inside may be as much as 150 feet from the injury in the membrane. This, incidentally, SYSTEMS OF WATERPROOFING 37 emphasizes the need for making the membrane adhere to the structure. To avoid possible injuries to the membrane during construction due to the causes mentioned above, temporary protection should be provided according to circumstances; for example, on the floor of a structure, by laying a gang-plank or enclosing the area with an improvised board fence; or if on a wall, by bracing strips of wood against it, especially to hold up the loose lap of the membrane and not allow it to dangle. Other expedients will suggest themselves as the need arises; the important thing to remember is that any properly designed protection will greatly minimize the above dangers. After construction there should be placed on or against the water- proofing a protective coat of metal at the most vulnerable points, 2 Layers of Brick / 4* 0" Sewer in Asphalt Maetic FIG. 10. Roof of Ventilating Chamber Waterproofed with Sheet Lead Membrane. and a protective coat of cement mortar or concrete, 2 to 4 inches thick, over the rest of the waterproofing. Fig. 10 shows one way of avoiding these dangers, by substituting a sheet lead trough for the regular waterproofing between a sewer and the top of a bay over a subway ventilating chamber. The protective concrete should preferably be reinforced, though this is not always necessary. A course or two of bricks, or a wall of flat or hollow terra-cotta tile are also good protective mediums. On horizontal surfaces, the hollow terra-cotta tile should not be used. The 3- or 4-inch concrete protective coat is the best in most instances because it is the least pervious. But in all cases the protective medium should be com- plete and cover every inch of membrane, and not as shown in Fig. 11 or Fig. 12A. Fortunately engineers are fast learning the folly of such malpractices as are depicted in these illustrations. 38 WATERPROOFING ENGINEERING Then again, in protecting waterproofing membranes or surface coatings, insufficient consideration is often given to the end laps. Yet it is no less important and necessary to protect the ends than the rest of the membrane or surface coating. It should also be observed that in placing the protecting covering of whatever material, it is of primary importance not to make water seams of construction joints; in other words, joints in protective coverings or layers should be made to offer the greatest resistance to the passage of water. A case in point is well illustrated and self-expkiced in Fig. 12 wherein the conditions referred to here are manifested in a striking m Exposed Membrane FIG. 11. Application of Waterproofing Membrane with Insufficient Protective Coating. way on a very important work. The improved methods of pro- tecting such ends are simple, easily constructed in the field, and cheap from every point of view. A waterproofing membrane of any material or a surface coating of bituminous material will last very much longer and render better service when properly protected. In fact, even a 1-inch mortar coat is remarkably effective in this direction, and is sometimes used even on bridge floors. But, in general, for railroad bridges, which are subject to considerable vibration, a sheet mastic of about this thickness is preferable. It is best to place the protective medium not later than one or two days after the waterproofing is completed. Where concrete constitutes the protective medium, it should be poured from the SYSTEMS OF WATERPROOFING 30 least height possible, as depicted in Fig. 13. Also, in depositing heavy backfill on or against such a comparatively thin layer of concrete, care and judgment must be exercised not to break or SHOWING WRONG METHODS OF IMPROVED METHODS OF FINISHING OFF WATERPROOFING PROTECTING WATERPROOFING ENDS Note exposed lap of membrane S 4, c Concrete /Wate^oofing f N te overla PP in & of Protective concrete . *- * \ \ A r- s> T -^ * Crown of Arch / -_[ Crown of Arch i . f Crown of Arch "J 2" in Earth . 11 / --- TV [i JF /^ - K / 3 fa v If A B LJLL -3 ; . 3 \ ^C) * ** o : / II " P c. O Ul .ts tn ?# '!>". -'/i \ ^vK- _ ^v W * ^. . .d-4.A_ ^x "S '^4 || Jr / ^ H ft '* AJ I i :1%- '4 ~c :':-:^.:.^ m *0 '4 :a :^ \&\ O ^ ' 'A- f i 1 '< ' \G j :0* ; - a & 7 '.' ;s^. ; i ^ &'- d'. '.-'.' D ~^~ ^ : ^; 1 SYSTEMS OF WATERPROOFING 45 to it and the other half slitted radially adheres to the first ply on the wall Or other surface. The successive plies are laid in the same manner. A finishing ply is then placed covering the slitted fabric and this ply is cut only to allow the pipe to pass through. Satisfactory and permanent waterproofing in the vicinity of steam pipes is difficult to obtain. This may be accomplished, however, by placing a strip of sheet lead of sufficient length and width, and about J-inch thick, between the waterproofing and the supporting material of the steam main. It is understood, of course, that the main -itself is first adequately insulated to prevent its radia- ting heat from affecting the waterproofing. A satisfactory method for insulating steam pipes is to surround them with a blanket of ten or twenty plies of untreated asbestos felt, encasing this with large semi-sections of vitrified sewer tiles, and packing the space between the two with coarse asbestos fiber. The whole must be well sup- ported on concrete or vitrified two- or four-way tile ducts or other suitable non-conductive material, all depending on the size of the steam main, location and working conditions. The above expositions are general. Modifications will often be necessary on such structures as railroad bridge floors, reservoirs and buildings, but the fundamental principles are the same. Hence, it is not necessary to consider here how each kind of structure is to be waterproofed. The main point to remember in regard to all types of waterproofing and all manner of structures is to suit the waterproofing to the structure, taking all local conditions in to con- sideration, including climate, purpose and type of structure. In the majority of cases, it may here be noted, successful and durable waterproofing depends not only on conscientious labor, but more particularly on expert supervision. Use of Special Membranes. A modification of the usual long- strip, built-up, elastic type of membrane consists of a membrane made up of small, square layers of cotton fabric,* thoroughly satu- rated and heavily coated on both sides with a suitable bitumen and often with a special, that is, a proprietary bituminous compound. The cotton fabric commonly used has a thread count of 66 by 44 per square inch, weighing about 4| ounces per square yard. When treated, the fabric has an average thickness of J inch, and weighs about 4| pounds per square yard. The operation of saturating and coating the strips of fabric is done in the field immediately adjacent to the work because the compound used must possess considerable adhesiveness so as to stick well to the applied surface * Developed in 1907 by Oscar Sheffield, and in practical use since 1909. 46 WATERPROOFING ENGINEERING and to itself when lapped to form the membrane, hence it is imprac- ticable to handle the finished sheets between the factory and the field work. The treated sheets, which are best handled when about 1 yard square, are laid over the surface to be waterproofed with not less than a 2-inch lap. The laps are then sealed with a hot smoothing iron to insure perfect adhesion, after which they are recoated with an additional layer of the bituminous compound. The membrane is laid so as to be continuous and unbroken over the entire area waterproofed. See Fig. 17. The protective masonry is then applied as on the built-up membrane. FIG. 17. Applying Treated Cotton Fabric. Any good quality of cotton or jute fabric is suitable for this type of membrane, but only a strongly adhesive, tough and elastic bitumen, and one that will remain plastic at all seasons, can be used satisfactorily for this purpose. At the present time only one pro- prietary compound is extensively used for this modified membrane. This compound consists of several hydrocarbons, each possessing different physical properties but mixed in proportions to secure the desired consistency. Considerations for Selecting Membrane Reinforcement. The following question often arises in waterproofing design: What reinforcing material is best adapted for the membrane system of waterproofing? In other words, is treated felt, jute fabric or cotton drill to be preferred, and under what conditions or for what types of SYSTEMS OF WATERPROOFING 47 structures is each best suited? This can best be judged and answered from experience. Felt was used extensively on the old Manhattan subways in New York City, in the form of a membrane composed of six plies of felt and seven coatings of asphalt, surrounding the structure like an envelope. But it has not given entire satisfaction apparently because this type of membrane has insufficient tensile strength, so that when cracks developed in the concrete shell, it too would break somewhere. Had this membrane been reinforced with two or three plies of jute or cotton fabric, this fault would not be operative in producing leaks. Then again, the felt in the mem- brane forms a stratified sheet with as many laminations as there are plies used. This creates many surfaces where water may creep along under certain conditions, and cause damage. Its close texture also prevents the escape of entrained air during its application, which tends to create air pockets between the plies. Besides, there is also present the capillary action of the felt fibers, though this is not peculiar to felt alone. It has, however, a very extensive and successful use on all manner of structures notwithstanding, and is cheaper per unit of area than either cotton or jute fabric. Jute fabric, on the other hand, such as was used on the new Dual Subways in New York, also in the form of a membrane (com- posed of three to six plies of fabric with from four to seven coatings of coal-tar pitch) , has thus far given entire satisfaction, and apparently for the following reasons : The fabric being of the open-mesh variety (and only such was used), permits the bonding of successive plies, thus forming a unit-membrane of bituminous material with the fabric acting as so much reinforcement. The open mesh automati- cally prevents the formation of air pockets between the plies. This fabric has considerable tensile strength and can easily stretch, with- out tearing, over ordinary cracks. This allows the bitumen to heal on favorable occasions. There is also somewhat more bitumen present in this membrane than is ordinarily present in a felt mem- brane of an equal number of plies. Tests by the author have proven that jute fabric can be thoroughly saturated and coated with either asphalt or coal-tar pitch, and when so treated is well preserved against decay. It is from 50 to 100 per cent more expensive than treated felt. On some construction work raw burlap has been used (that is, burlap not treated), but such practice is open to the following objections: The hot bituminous binder applied to it in the field cannot properly saturate it, neither is the workmanship in the field always conducive towards such accomplishment, if that were at all 48 WATERPROOFING ENGINEERING possible. And without proper treatment, the jute fabric will be comparatively short-lived, especially if exposed in the earth with insufficient binder; but this is equally true of the felts and cotton fabric. The use of treated cotton drill is undoubtedly very good for membrane waterproofing, especially if it is strong and well-treated. In fact, its use is only prohibitive on account of its relatively high cost when compared with either treated felt or jute fabric, especially in view of the fact that the latter is not less efficient in any regard. All are vegetable products and therefore require equally thorough saturation. The cost of the cotton drill, which is at least double that of jute fabric and quadruple that of treated felt, also because a more or less laminated sheet rather than a reinforced unit membrane is formed, especially with the, ordinary variety of close-woven cotton fabric, suggests that it be given preference only after careful economic consideration. Saturated cotton drill has been used quite extensively on the Boston subways, and, except for some few leaks that have developed, has given reasonable satisfaction. The very best and most efficient type of membrane is one composed of treated fabric, with small (in size and number) open mesh, united with a uniformly thick bituminous binder. However, for ordinary purposes and for rigid structures, felt is entirely serviceable. Storing and Unrolling Felt and Fabric. All waterproofing mate- rials are injured by improper storage and usage, particularly the felts and fabrics. Fabric and felt are delivered on the work in rolls usually wound on wooden cores (for types of cores see Fig. 82), from 100 to 150 yards in length and in varying widths from 32 to 50 inches, the 42-inch fabric and 36-inch felt being most common. The rolls should be stored in a dry place, and in warm weather the fabric rolls must not be stood on ends. The most satisfactory way is to pile the rolls not more than 2 or 3 feet high, so as to insure uniform bearing along their length, and never to pile them criss-cross. As it is possible to wind felt much tighter than fabric rolls, they may be stored lying down or standing up. In all cases, both materials should be protected from the weather and from heat at all times. Due to improper storing, fabric rolls become distorted and other- wise injured, and are therefore often difficult to unwind, resulting in tearing the fabric. Distortion is a defect which tends to create " waves," which persist when the roll is unwound and tend to occlude air in the membrane. Torn or badly wrinkled fabric should not be used. The surface on which the felt or fabric is unrolled preparatory to its use in the membrane should be clean. SYSTEMS OF WATERPROOFING 49 Precautions When Heating Coal-tar Pitch and Asphalt. Where coal-tar pitch is used as the binder for membrane waterproofing, it should be heated gradually up to the proper consistency for applica- tion. This is usually at a temperature between 250 and 350 deg. Fahr. (121 and 149 deg. Cent.) for a coal-tar pitch with a melting- point between 115 and 125 deg. Fahr. (46 and 51.6 deg. Cent.). Where asphalt is used, it too should be heated gradually, but its working temperature is higher, hence it may be heated to a tem- perature between 300 and 350 deg. Fahr. (149 and 177 deg. Cent.). Having reached the proper temperatures, the fire should be banked. Heating a 50-gallon kettle full of coal-tar pitch or asphalt to the required temperature for application, by means of a wood fire, should take not less than three to four hours, for the pitch, while in the case of asphalt heat may be applied more rapidly, but should take not less than two to three hours. A more violent heating in either case destroys these materials, especially the coal-tar pitch. The danger of overheating, burning or coking (particularly the pitch) is constantly present, and cannot be too strongly guarded against. One way to prevent overheating is to stir the pitch occa- sionally during the melting process, and frequently after it has melted until it is all used. Overheating is preceded by the rising of excessive fumes of a light bluish tinge. Burning is indicated by the rising of yellow fumes from the surface of the pitch. The odor or cackling sound is not an indication of the condition of the bitumen. Neither is the practice of sticking a piece of wood into the molten bitumen a real indication of its degree of heat or of its condition. Coking the pitch is indicated by the formation of a more or less thin crust or coating on the bottom and sides of the melting kettle. When by accident or otherwise the pitch is slightly burned, new pitch should be mixed with it before using, and, if badly burned, the pitch should not be used at all. It is very essential to the " life " of the pitch not to subject it to prolonged heating, even at a low temperature, as this drives off some of the volatile oils which are a valuable constituent of the pitch. The best practice is to heat only sufficient material for one day's use. Asphalt, though not as readily affected by heat as coal-tar pitch, also requires in its use the observance of the above rules. The burnt condition becomes manifest by the rise of blue fumes from the sur- face of the asphalt, and when this happens, the fire should immediately be extinguished, and additional asphalt put into the kettle. If the heat has been excessive and protracted, and if the blue fumes have been excessive and constant for more than an hour, the asphalt 50 WATERPROOFING ENGINEERING should not be used, because it will undoubtedly have changed or lost some of its properties. The effects of prolonged heating are inversely proportional to the natural hardness of the bitumen. Precautions should always be taken against fire in the heating kettles, and if one starts water must not be used to extinguish it. As the temperature of the pitch or asphalt during use is far above the boiling-point of water, the result of throwing on water may be serious. Fires may best be put out by the use of sand or steam. As pitch and asphalt hold heat for a considerable time, the workmen should be warned of the danger of being burned by these materials. Whenever it becomes necessary to transport bitumen, as when the particular waterproofing job is beyond a 500-foot radius from the location of the heating kettles (which is quite common on large construction work), small portable kettles are used for transporting the pitch or asphalt. The same precautions must be taken to avoid burning and coking the bitumen in these kettles as was previously explained for the stationary heating kettles. Where the bitumen is carried in buckets, it is best not to allow these to stand more than a few minutes before using, as the temperature falls rapidly and the material thickens. This condition prevents uniform spreading when the bitumen is mopped on the felt or fabric in making the membrane. Proper Use of Kettles and Fuel when Heating Pitch or Asphalt. Coal-tar pitch and asphalt have no serviceable affinity in water- proofing by the membrane or sheet-mastic systems. Their mixture produces a product which resembles putty in some of its physical properties, except when the amount present of one or the other does not exceed 5 per cent. Hence the heating kettles should not be alternated; i.e., kettles used for melting pitch should not be used for melting asphalt or making mastic, and vice versa. Where kettles must so be used, it is necessary to clean them, especially where either material has caked on the sides and bottom of the kettles, as often happens. In fact it is good practice to thoroughly clean the heating and mastic-mixing kettles, portable kettles and pails not less than once a week even though their use was intermittent. Kettles encrusted with bitumen or mastic require more fuel and time for heating the contents. The life of the kettle is also reduced by the presence of caked bitumen or mastic. The easiest obtainable and cheapest fuel for heating kettles is discarded construction timber. Staves of asphalt or pitch barrels are objectionable on account of the unbearable volumes of smoke they produce. Much trouble and a public nuisance would be avoided SYSTEMS OF WATERPROOFING 51 if there was a law prohibiting their use in city streets. Cord wood is the best to use, because with it a smouldering fire may be main- tained for a long time. This keeps the bituminous material hot without burning it. Differentiating between Coal-tar Pitch and Asphalt in the Field. Engineers unfamiliar with bitumen find it difficult to distinguish between coal-tar pitch and asphalt, consequently, mistakes some- times occur by using one for the other. Asphalt may be a product of asphaltic petroleum, a refined natural asphalt or a mixture of both. Coal-tar pitch is a product of the destructive distillation of coal in the manufacture of coke or illuminating gas. The follow- ing characteristics will aid in identifying each on the work. Asphalt, when newly cut, is a bright, lustrous black. It has a pungent and somewhat rancid odor and taste. With the application of heat of equal intensity, it requires longer heating than coal-tar pitch to be brought to the same liquid condition or equal temperature. When asphalt burns without flame its fumes are decidedly blue. Coal- tar pitch, when newly cut, is somewhat of a dull black and more brittle, as compared to asphalt. It has an aromatic taste and odor, which is characteristic of pitch only. When coal-tar pitch burns without flame, its fumes are a dense, greenish yellow. The safest and most advisable thing to do where both materials are used on the same work is to require the manufacturers to mark or label the containers, so as to make identification easy and certain. Coal-tar Pitch Versus Asphalt for Waterproofing. Whether asphalt or coal-tar pitch is to be preferred for membrane water- proofing is still a mooted question. No doubt, for certain special uses, as for instance, where the temperature varies widely, the asphalt is a preferable material because it remains soft and workable through wide temperature ranges; if the temperature varies but little, as it often does in underground work, straight-run coal-tar pitch will give better results on account of its greater chemical stability. But on general construction work, a good quality of either material is equally serviceable, the prevalent contrary view among engineers notwithstanding. The author's experience has led him to the conclusion that certain brands of asphalt now on the market are even to be preferred to some grades of pitch, for this reason: The asphalts (all too few, though) as now refined, have been constantly improving in quality, while coal-tar pitch did not keep pace. In fact, in the last decade or so, on account of the increasing value and importance of the by-products from coal tar, and, due to the keen competition in the waterproofing field, the 52 WATERPROOFING ENGINEERING quality of pitch has materially suffered. Where the quality of pitch or asphalt can be controlled or ascertained and verified, how- ever, their preference for waterproofing purposes, assuming the con- sistency to be right for the climate or local requirement, becomes a question of cost. The heretofore superiority of pitch was due to the fact that asphalt was often produced as a by-product in oil refineries. Now the practice is being reversed, hence the improved quality of asphalt now available. But of course, good straight-run coal- tar pitch is also available. The point to remember is that both materials, if of good and certified quality, are practically equally serviceable, with the exception noted above with regard to adaptability. MASTIC SYSTEM OF WATERPROOFING Definition, Purpose and Development. The mastic system of waterproofing consists of (1) the application of sheet mastic (com- posed of asphalt or coal-tar pitch, sand, grit and cement or stone dust), in the form of a comparatively thin layer, which more or less surrounds the structure to be waterproofed; (2) a brick-in-mastic or tile-in-mastic layer composed of a course or two of bricks or tile, the joints being filled and all faces covered with a bituminous mastic, the course or courses covering the structure below ground- water level. The sheet mastic varies between J inch and 2 inches in thickness; the brick-in-mastic varies between 2\ inches and 8 inches in thick- ness. The brick-in-mastic layer, being between five and eight times as thick as a 3- or 6-ply membrane, and from four to five times as thick as the sheet mastic, is usually used where great water pressure exists. It is the most dependable system of waterproofing, though also the most expensive. In underground construction where head- room is a factor, or in general where insufficient space exists for the application of one or two courses of brick-in-mastic, and where sheet mastic cannot be used, as for instance, on sidewalls of subsur- face structures a fabric membrane of from 4 to 8 plies is usually sub- stituted. A felt membrane of an equal number of plies should be used only when reinforced with 1 ply of fabric for at least each 3 plies of felt. This precaution is not necessary, however, on very rigid structures, or where expansion joints properly distributed in the structure, are provided. Almost simultaneously with the development of the fabric membrane went the development of the sheet mastic and the brick- in-mastic layers. Originally, a coating of mastic (composed of rock SYSTEMS OF WATERPROOFING 53 asphalt, fluxed to the proper consistency) between \ and \\ inches thick, was used mainly on horizontal surfaces.* In an effort to increase the depth and weight of this coating for waterproofing purposes, both on horizontal and against vertical surfaces, bricks or tiles were introduced between thinner layers of mastic. Finally, even the brick joints were rilled with mastic, resulting in the present day brick-in-mastic layer or envelope. Where this scheme is used for waterproofing, the materials are always incased between concrete or other masonry surfaces. Applying Mastic Waterproofing. Sheet mastic for waterproofing is mostly used on railroad bridges though it has been employed on underground construction. It is most extensively used as a water- proof floor for buildings and railroad stations. Sheet mastic is, however, subject to abuse in its manufacture and application. For instance, the quantities of the various mineral ingredients might be poorly proportioned, resulting in a mastic that is too soft or too hard; the quantity of bitumen might be insufficient to give good cohesiveness and elasticity to the mastic. The sheet mastic might be applied without sufficient precautions to prevent cracks produced by movement due to temperature changes especially over large areas. While the particular purpose in hand should always be considered in proportioning of the ingredients for making sheet mastic, still the following general directions should be adhered to: the bitumen and the sand should each be not less than 10 per cent of the finished mastic; the fine mineral dust, whether limestone dust or cement, should be not less than 45 per cent, and the grit not more than 30 per cent of the finished mastic; the remaining 5 per cent is sufficient, if carefully apportioned, to take care of any special requirements of the mastic. When serving only as a waterproofing medium, sheet mastic must be continuous over the surface to which it is applied, but its abutting extremities must not be relied on to make a watertight connection with steel or concrete without special provision being made to obtain such a condition. This may be accomplished by a cove finish of the ends or by the use of an adhesive, plastic joint filler. Often sheet mastic is used in conjunction with other systems of water- proofing as, for example, to cover a felt or fabric membrane. With due precautions in its application, sheet mastic constitutes a good * The use of sheet mastic (or sheet asphalt as it is popularly called) dates back to 1838, when it was used to make sidewalks in Paris. It was made of a bitu- minous limestone from Seyssel and Valde Travers, and since then nearly all European asphalt paving has been done with this asphaltic limestone. 64 WATERPROOFING ENGINEERING waterproofing medium, comparable to the brick-in-mastic system. Sheet mastic can be made to withstand shock and vibration without cracking by introducing a wire mesh or cloth reinforcement between equal thicknesses of mastic forming the layer. It is much cheaper than brick-in-mastic, but is not as generally applicable. Compared to felt or fabric membranes, the use of brick-in-mastic to waterproof a structure is more costly, and its application often more difficult and more exacting. The reason for this is that the amount of labor necessary for preparing the mastic and laying the courses to form the envelope about the structure is considerably more, as also the quantity of material required for equal areas to be cov- ered, than the bituminous membrane. Figs. 19 and 20 illustrate some of the difficulties contended with in the application of brick- in-mastic to an underground structure, such as a subway. The section in Fig. 18, representative of the construction of the new Dual Subway in New York City, shows a typical arrangement of the waterproofing used on this work. The brick-in-mastic, by its sub- stantial nature, protects the floor from percolation due to pressure, and the bituminous membrane protects the roof from seepage of ground water. The condition of a structure to be waterproofed is not always what it should be to receive the envelope of brick-in-mastic, hence the structure must be made adaptable by artificial means such as smoothing, drying, cleaning, etc. It may not be feasible to wait until the concrete dries before applying the bri3k-in-mastic, or the weather may make it difficult to obtain a dry surface. Where a wet or damp surface is unavoidable, a ply of felt or fabric or a mem- brane consisting of the two CD nbined should be placed thereon and its surface mopped with asphalt if asphalt mastic is being used, or with coal-tar pitch is pitch mastic is used. Pools of water and a decidedly wet concrete should first be made reasonably dry by suit- able means before this dry ply is laid. But no dependence for water- proofing is to be placed on any form of dry ply. The waterproofing mastic is usually brought to the place of application in portable fire kettles or small pouring pails. The mastic should not be allowed to stand in these for more than a few minutes before using. Failure to observe this results in a loss of heat and uniformity of mixture due to the quick settling of the mineral aggregate. In any case the mastic should be well stirred before pouring it on the prepared surface. The carrying pails must be scraped after each pouring to avoid caking of the mastic on the bottom by continued settlement. The mastic should always be SYSTEMS OF WATERPROOFING 55 = 2.1019, tsp<",, P M ' bg ,,XJo < 8 aijo^Q |3ni H-A,,* ^ 8 p M -bs % V 56 WATERPROOFING ENGINEERING spread out to a uniform and reasonably thick film (about J inch) before laying the bricks therein. The bricks, whose function is to give a substantial and thick waterproofing layer, are laid in the mastic so as to be completely surrounded by a film not less than f-inch thick. In no case should brick touch brick. A simple method of obtaining good and com- pletely filled joints around the bricks is to slide each brick into place, somewhat diagonally and with a slight pressure downward. This will invariably bring the bed mastic up into the joints. Spalls should not be used under any circumstances. An effort should be made to use whole bricks, and bats but sparingly. In applying more than one course of brick-in-mastic it is best to build each almost simultaneously, with the lower course not more thaa a few feet in advance of the upper. Where two courses are decided on (in which the bricks are ordinarily placed on their largest bed) it will often be found profitable without materially reducing the-: effi- ciency of the envelope to build a one-course envelope, but with the bricks laid on the narrow side. Ihis scheme will effect a saving of 22 per cent in material alone. Each course of bricks is to be covered with mastic so that all joints and hollows are filled, making the surface even. When spreading the top coat of mastic, care is to be exercised in joining successive pourings. This top coat sometimes becomes pitted or perforated with numerous pinholes exposing the bricks. This may be largely overcome by increasing the amount of the fine mineral aggregate or by adding a small amount of asbestos fiber. When such a perforated condition is detected in the finished envelope it should be resurfaced with the pure bitumen. Laying protective concrete should proceed immediately or shortly after the surface mastic has cooled. The top or exposed film of mastic covering the bricks must be cleaned in a manner similar to that previously described for membranes. Where temporary construction timber cannot be removed during waterproofing opera- tions, these locations must t>e taken care of similarly as described under the " Membrane system." The forms placed about post holes to prevent the protective concrete from flowing into the same, should be made watertight to avoid coating the asphalted bricks as it is difficult to remove the set mortar afterwards. In pouring the protective concrete on the mastic, it is safest not to exceed a drop of 6 feet in height to avoid injuring the top coating. The surface of the protective concrete should be troweled smooth. SYSTEMS OF WATERPROOFING 57 Precautions when Joining New and Old Brick-in-Mastic. The ends of the courses at the finish of each day's work, or when work is temporarily discontinued, must be well mopped with asphalt or coal-tar pitch, depending on the kind of mastic used, leaving no bricks uncoated. To preserve the physical condition of these ends, 2-inch boards may be laid up against them, especially where resump- tion of work may be delayed for a long time. In commencing the new work, the old surface should be cleaned and softened so as to properly join with the new mastic. The use of a gasoline torch or the burning of some gasoline on the surface is sufficient to accom- plish this. Where temporary braces, posts and other supports are used on the work and are not moved to accommodate the brick-in-mastic layers, all four sides of such post holes should be stepped when more than one course is used (see Fig. 16). In waterproofing these post holes after removing the posts, all surfaces are to be carefully cleaned and remopped with bitumen. The mastic is then poured on the pre- pared area and the bricks embedded therein in the ordinary way. It is advisable to dip these bricks in bitumen or mastic before laying. In fact, all possible precautions should be taken to secure an absolutely watertight joint on all kinds of patch work. Placing Mastic around Projections and in Vicinity of Steam Pipes. If, through a masonry surface which is to be waterproofed by the application of a layer of sheet mastic or brick-in-mastic, such objects as pipes or rods project, careful workmanship is required to make these locations watertight. Whatever the object be, that part of its surface which will be included in the waterproofing layer must be cleaned thoroughly. If these objects project through a floor or roof, then it is well to leave an open ring about 2 inches wide, completely around them, as the course or two of brick-in-mastic is laid down. Then this ring space is preferably filled with a mastic of softer consistency than that used ordinarily, or with pure asphalt. Sheet mastic may be applied without this temporary space around projecting objects. If objects project from vertical surfaces, it is first of all necessary to make the form (required for placing brick- in-mastic against walls) fit snugly around the object. Then the bricks should be so laid in the mastic at these projections as to leave a space about 1 inch wide around them, to be filled by the mastic. A better bond will be secured between the mastic and the pipe, rod, or other projecting objects, if these are first swabbed with pure bitumen. In some instances, where the importance of the work warrants it, the efficiency of these connections will be enhanced 58 WATERPROOFING ENGINEERING by the judicious application of waterproofing felt or fabric, as for instance, if the joints were made as described under " the membrane system"; then, by the further filling of the ring spaces with mastic or pure bitumen, more positive joints are secured. In the event that steam or hot- water pipes or mains project through the masonry, then it is first necessary to insulate them so as to reduce the effect of their radiating heat to a minimum. The usual method for doing this is also described under " the membrane system." Preparation of Wall Surfaces for Brick-in-Mastic. When exterior waterproofing is intended for an underground structure running through rock, an effort is made while excavating to leave the natural sides as vertical and smooth as possible. But this is never attained. Hence a sand wall of concrete is applied against the natural rock to supply a vertical and smooth surface. This acts as the " armor- coat " for either the membranous or mastic type of waterproofing. Excavation in earth requires the customary sheet piling and bracing. This sheet piling is generally placed sufficiently outside the neat line to permit the building of either a one-course brick or terra-cotta hollow-tile wall. This wall then acts as an " armor-coat " for the waterproofing. In some instances steel or wooden sheet piling is so placed as to preclude the possibility of building a masonry wall within its confines, then this piling is made to act as the armor-coat for receiving the waterproofing. (Fig. 19.) These conditions, however, only occur on large and difficult work where they must be given special consideration. If the masonry armor-coat against the rock surface or sheet piling is too wet to receive the waterproofing, or when the sheet- piling armor is in a similar condition, then a so-called dry ply of either felt or fabric, or a combination of the two, is first applied. Where water is actually running over the face of the wall or sheet piling, it should be diverted temporarily. This may be done either by inserting sufficient bleeders at the best elevation, or by attaching a strip of tin in the shape of a trough above the space to be water- proofed. Plaster of Paris or cement may be used for attaching this strip. If, by these methods, the surface cannot be made thoroughly dry, a dry-ply of felt and fabric combined is to be hung up against the surface. The brick-in-mastic is then laid against it in such a manner as to permit the water to flow down and progressively forward and out from behind this dry ply. Wherever there is no direct water to contend against, as above noted, the dry ply may consist of strips of felt or fabric, mopped in the usual way. In building the armor- SYSTEMS OF WATERPROOFING 59 coat of concrete, the form for it should be made rigid so as to avoid bulging. Neglect of this precaution causes a reduction in the cross- section of the brick-in-mastic wall, a condition to be avoided, as eventually it may be the cause of leaks, due to the careless practice FIG. 19. Showing Partly built Main Wall, 1, and Forms for Brick and Mastic, 2. Note Top Row of Bricks Covered with Mastic, and Sheet Piling left in Place Acting as Armor for Waterproofing. of filling the narrow parts of the forms with small pieces of brick, or squeezing in whole bricks and thus thinning the joints. Precautions for Setting-up, Filling and Stripping Forms for Brick-in-Mastic Walls. In building brick-in-mastic walls, forms are necessary mainly to allow the mastic to set, and in warm weather, even after. Fig. 19 shows a form for a two-course mastic wall in 60 WATERPROOFING ENGINEERING 2 Courses Brick-in-IVIastic FIG. 20. Building of Two-course Brick-in-mastic Wall, Showing Form, Form Bracing, and Sand Wall. SYSTEMS OF WATERPROOFING 61 course of construction against a sand wall preparatory to the placing of the finished wall within. Therefore, after the surface of the armor-coat has been properly prepared, the forms should be placed the required distance from it. This distance is governed by the manner of laying up the bricks; i.e., if the longest edges of the bricks are perpendicular to the wall (all bricks being laid as headers) 8J inches form space is required; if they are laid parallel to the wall in two courses, 8 inches are required, and in single courses, 4 inches. Of course this assumes the use of common red brick, as no better or special kind is necessary. The height of form sections are not to exceed 3 feet, so as to enable the waterproofer to easily reach the bottom in laying the bricks. In bulkheading the forms, tight joints are necessary. To insure the easy and successful stripping of forms, the inner surfaces of the forms are to receive a wash coat of neat cement, or have a strip of felt attached. Washes of lime or clay may also be used to good advantage, but in no case should lumpy clay be applied. Any of these coatings are best applied before the forms are set up. When the forms are erected, a pail of mastic is poured and spread uniformly therein. The bricks are immediately embedded in the mastic, usually on their largest bed and with their longest edge parallel to the wall. In laying the brick no mastic should be allowed to collect or extend beyond any course of bricks. In laying the successive courses of brick, they may be made to break joints in the same manner as in a brick and mortar wall, but this is not essential. Where the space between the wall and the form is not wide enough to allow one or two bricks as the case may be to be laid on their largest bed and with proper joints (in the manner described above) due to bulging of the sand wall or armor-coat, the bricks should be laid so as to leave more mastic in the joints and faces. Sometimes a ply of fabric is added for each inch of reduction of form width due to this bulging, but this is inadequate and should be guarded against. Settlement and Bracing of Brick-in-Mastic Walls. Where the mastic forms must be removed prior to the building of the main wall, the mastic wall should be well braced to prevent buckling and undue settling. In warm weather the removal of mastic forms should be done only shortly before building the main wall. Where failure to observe this rule has caused any decided deformation in the mastic wall, this portion should be cut out and properly replaced with new materials. But quite often it will be possible to push the bulge back 62 WATERPROOFING ENGINEERING into place by applying a constant force, pressing on as large an area of the bulge as possible. All asphalt mastic on cooling will reduce in volume and settle, (about | inch in a height of 10 feet per 30 deg. Fahr. (16.5 deg. Cent.) change in temperature for a 2 : 1 : 1 mastic) therefore no concrete should be placed on top of a mastic wall until complete cooling and settlement has taken place in it. Neither should a mastic wall be counted on to carry any weight at any time because it cannot per- form this function by the very nature of its make-up. On extended flat surfaces, however, it can be made to safely carry about 300 pounds per square inch at about 60 deg. Fahr. (15.5 deg. Cent.) if movement in the layers is impossible. Where a mastic wall is to join the brick-in-mastic on the roof of a structure, it should be brought up to the level of the roof-masonry, and allowed to settle and cool, then the mastic on the roof should be laid and joined to the wall mastic. The protective concrete or other masonry is then laid so that its joints are not directly over the joints in the mastic waterproofing. Materials for Making Mastic : their Properties and Proportions. Asphalt or coal-tar pitch may be used for making mastic. Both must be carefully selected and tested to insure their adaptability. The usual practice is to use a minimum of 33 per cent of bitumen, but this may be decreased to 25 per cent where a stiff mastic is required, or increased to 50 per cent where a less viscous mastic is desired. The mineral aggregate, the presence of which tends to increase the tensile strength of the binder, is usually sand, cement or limestone dust, and sometimes asbestos fiber is added as a filler. The proportions are often arbitrarily and carelessly specified. The aim in this regard should be to proportion the mineral filler to produce maximum den- sity which insures maximum strength. The sand for making mastic should all pass through a 10-mesh sieve. It should never be used when wet or moist, and in general, should be heated before using. (Figs. 77 and 78 show the customary ways of doing this.) This will lessen the formation of bubbles and pin holes in the mastic caused by the escape of the occluded moisture. The sand should also be clean, free from dirt, silt, or vegetable matter. Any cement in good condition is suitable for making water- proofing mastic. Fineness of the material is the important factor, because the finer the grain, the more intimate is its incorporation with the bitumen. The limestone dust need not be as fine as the cement, but it should pass at least 80 per cent through a 100-mesh SYSTEMS OF WATERPROOFING 63 sieve, and 10 per cent through a 200-mesh sieve. Slate dust is sometimes substituted, but it usually lacks the fineness of either cement or limestone dust. Bricks used for brick-in-mastic waterproofing should be of good quality common brick, burned hard entirely through, regular and uniform in shape and size and of compact texture. They should also be heated to complete dryness before using, and so heated as to remain practically clean, i.e., free of excessive soot. The various methods for doing this are discussed below. The two-thirds mineral aggregate referred to above may consist of a mixture of sand and cement or sand and limestone dust with a reasonable amount (not more than 1.5 per cent), in either case, of asbestos fiber. The latter material, however, may be dispensed with, as it is only necessary in special cases, as, for instance, on the top or final coating of the mastic layer when this is located a few feet below ground surface. The sand and cement is usually mixed in equal proportions by weight or volume, but it would be much better to mix these with due regard to the percentage of voids in the sand. In the rare instances where mastic is to be laid in a very wet location, more mineral matter should be used, as this will increase the weight of the mastic and decrease the tendency to create bubbles in the asphalt due to the steaming and upward pressure of the water, also when it is to be used on an incline, as more sand stiffens the mastic. In the mastic that is used as a top coating for the upper course of bricks, less sand should be used. This will leave the mastic more ductile and plastic, permitting it, if cracked, to heal more readily when the temperature is suitable An addition of asbestos fiber may be made instead of reducing the sand, as this also gives a more flexible coating. Hand- versus Machine-made Mastic. When making water- proofing mastic by hand, it is important to see that the sand and limestone dust are thoroughly dry. The sand and cement or lime- stone dust are first mixed in proper proportions and then put into the mixing kettle after sufficient asphalt has been melted therein. The temperature of the asphalt mastic should be kept between 350 and 400 deg. Fahr. (177 and 204 deg. Cent.) and coal-tar pitch mastic between 275 and 325 deg. Fahr. (135 and 163 deg. Cent.). The aggregate should not be dumped into the melted asphalt but sprinkled into it. Stirring the mastic must be continued until a uniform mix- ture has been obtained. This requires at least twenty minutes of continued stirring for a 50-gallon kettle. On large work a battery of mixing kettles is usually centrally 64 WATERPROOFING ENGINEERING located, but where the particular waterproofing jobs are beyond a 500-foot radius from the mixing kettles, the mastic must be trans- ported in portable fire kettles. The mastic in the mixing kettles is to be stirred before pouring into the portable kettles, and when it arrives at the place of waterproofing, the mastic should again be stirred before pouring into the carrying pails. No mastic from the hot portable kettles must be poured into the carrying pails unless it is to be used immediately, otherwise settlement of the aggregate results and the uniformity of the mixture is destroyed. The practice of making mastic by hand in open fire-heated kettles is as old as the mastic industry, which began between 1880 and 1885. But, though paving mastic has for many years been made by machine, floor and waterproofing mastic continue to be made by hand. This is partly due to the fact that (1) heretofore such mastic was not a commonly used material, (2) natural rock asphalt was mostly used in the belief that an artificial mastic was impossible or very inferior, (3) the secretiveness with which the mastic industry was developed,* and (4) the comparatively small quantities of floor mastic generally called for on any particular job. Making reasonably good mastic by hand is of course possible. But there are many drawbacks not usually considered. For instance; the consistency of the mastic is usually determined by the operator and hence no two batches are alike; neither are the proportions of ingredients constant, for they are usually dumped in by "eye"; then, what is worst of all, the man mixing the mastic naturally desires to lighten his labor and occasionally either does not suffi- ciently mix the batch, or adds more bitumen than the amount specified. All of these objections would be absent in a machine- made mastic, because the ingredients would necessarily have to be weighed or measured, as is done in mixing concrete by machine. The quality would also be easily regulated and the engineer could better inspect the work to see that his specifications were lived-up to, especially in the matter of cooking the mastic. On large work this is very important. A type of mastic-mixing machine which makes this possible, and indeed, makes a superior mastic, is shown in Fig. 67. The author, who has experimented with and observed the product of a machine of this type for a long time, can state confidently that it would be to the interest of the mastic industry to abolish the hand- mixed product and resort to a machine-mixed mastic, especially :2l ln the early days of the mastic industry it was not beneath some of those engaged in it to employ the tricks of witchcraft to fool the inquisitive. SYSTEMS OF WATERPROOFING 65 because of its economy. This economy results from the fact that the asphalt does not have to be first melted and heated as with the use of open kettles, and also because none of the mineral aggregates needs preheating. This is all accomplished in the drum of the machine, which, besides, can mix a much larger batch in considerably less time than men can mix it in open kettles. Machine-mixed mastic is, however, admittedly impracticable on small jobs, and has not yet been used for making waterproofing mastic such as described above, that is, its use heretofore has been limited to floor and paving mastic. Brick-heating Methods. In the use of bricks for brick-in-mastic, the question often arises as to (a) when the bricks should be heated, (6) to what extent they should be heated, and (c) by what method they should be heated. In answering these questions experience is the best guide. Bricks used as above noted should be heated (a) when the temperature is below 40 deg. Fahr. (4.5 deg Cent.), (6) when they are moist or damp (because either condition prevents good bonding between the bricks and the mastic) , (c) they should be heated to a degree not exceeding that which permits their being handled with the bare hands (because otherwise the mastic film surrounding the bricks will be melted off), and (d) the method of heating should be such as will not cover the bricks with an over amount of soot, because this tends to prevent proper bonding, and bonding is very essential to the continuity of the layer or envelope of brick-in-mastic. A method of heating bricks to be strictly avoided is the following: A small make-shift furnace, constructed by enclosing three sides of a convenient area with walls of either brick or stone, laid dry. These walls are of any convenient length and about a foot high ; the fourth side remains open and through it the fire is fed. On top of the walls is placed a wire screen strong enough to support about 200 or 300 bricks piled promiscuously. A wood fire is kindled underneath and the heat and smoke pass up between the bricks. This method not only fails to heat the bricks alike but also covers them with more or less soot, and is slow and wasteful. A better method is the following: A hollow cylinder about 4 or 5 feet in diameter is made by piling bricks one upon the other with loose joints, but interlocked so as to make the entire cylinder self-supporting. The bricks are laid on their largest bed and built up to a convenient height, say 3 or 4 feet. Next, a wood fire is made within the cylinder, or, better still, a coke fire is main- tained in a salamander placed within the cylinder. If a wood 66 WATERPROOFING ENGINEERING fire is used the flames should be kept low. This scheme permits the escape of smoke without covering the bricks with soot. The radiating heat dries the bricks to any desired degree depending on how long they remain near the fire. If a second row of bricks is built around the first one it will receive its incipient heat and as the inner cylinder of bricks is used up the outer one will gradually receive its share of heat. This method, however, is also slow. A mechani- cal brick heater is described in Chapter VI, and is the most efficient means for heating and drying bricks known to the author. Weather Conditions Governing Waterproofing Operations. To obtain the best results, no waterproofing should be done wherein ordinary bitumen is used as the cementing or binding material, especially in the form of a membrane, sheet mastic, or brick-in- mastic layers, when the air temperature is below 40 deg. Fahr. (4.5 deg. Cent.), nor during snow, rain, or drizzle. Coal-tar pitch chills rapidly in cold weather and will not stick well to cold masonry; and asphalt is even less adhesive to cold masonry. Neither pitch nor asphalt will adhere to a wet surface, therefore these conditions must be avoided. However, if the work be amply protected from cold and wet weather, waterproofing may proceed with due precau- tions for eliminating the hazards of these conditions. On the other hand, in warm weather, care must be taken to protect the finished waterproofing promptly, especially if it is exposed to the sun, other- wise expensive repairs may become necessary, before or soon after completion of the work. INTEGRAL SYSTEM OF WATERPROOFING Definition, Purpose and Development. The integral system of waterproofing is the process of making impermeable mortar or con- crete by incorporating in the mass, certain ingredients which act either as void fillers, as lubricants for the aggregate, or chemically upon the cement, thus densifying the mass. These ingredients con- sist of (1) finely ground powders, such as clays, silicates, feldspars and hydrated lime, which are usually mixed with the dry cement at the mill or on the work; (2) liquids and pastes such as stearate of lime (water-insoluble soap), sodium or potassium oleate (water- soluble soap), aluminum stearate, calcium chloride and oil com- pounds, which are usually mixed with the gaging water, though they are sometimes added to the mixed mass to form an integral part of the resulting mortar or concrete. The fillers may be inert or active. If inert, as the above powders SYSTEMS OF WATERPROOFING 67 are, they merely fill up the pores or voids inherent in the concrete, but if active, as the above soap compounds are, they may either unite with the cement or crystallize in themselves. The resulting compounds tend either to fill the voids and barricade the pores or to become water repellent. Most of the liquids and some of the pow- ders are inactive lubricants of a fatty nature, and these assist the aggregates to slide more compactly into place. The purpose of the integral system of waterproofing is to make concrete and mortar impermeable by the application of the water- proofing materials during the process of mixing, thus reducing the cost of the construction by eliminating the necessity for any addi- tional treatment. This system of waterproofing, however, does not remove the need for thorough mixing and careful placing of the concrete. The integral system of waterproofing is best adapted for treat- ment of structures in the course of construction, principally of the type not subject to vibration or shock. For water tanks, dams, foundations, and other stationary or rigid concrete structures, where absorption or percolation through the concrete may work serious havoc, it is particularly well adapted. However, the possibilities of making mass concrete impermeable by the simple expedient of care- fully grading and correctly proportioning the aggregate and pro- longing the time of mixing should not be forgotten. For railroad subways and bridge floors, this system should not be specified, no matter how promising may be the materials offered; for, even if the waterproofing materials added do not weaken the concrete (as sometimes happens when inferior compounds are used), they cannot prevent its cracking under vibration of traffic and the consequent percolation of water through such cracks. The incorporation of foreign ingredients in mass concrete to increase its density, or, what amounts to the same thing, decrease its permeability, is not so very old. Originally quick lime was used, then certain patented compounds began to appear on the market, such as stearates and resinates (water-insoluble substances), and finally hydrated lime began to be used for this purpose. In recent times numerous secret and patented compounds have been exten- sively used, but owing to a general dissatisfaction with the results obtained, they have received a considerable setback. And with them some very good materials were thrown into disrepute. The practice of adding an arbitrary but small percentage of cement over and above the calculated amount is quite prevalent, and often accomplishes the results claimed for many of these special compounds, 68 WATERPROOFING ENGINEERING Limitations of the Integral System of Waterproofing. The use of integral waterproofing compounds should be limited to conditions where certainty exists regarding character of stresses in the structure, and then only after the materials have been analyzed, tested and proven efficient. The following pertinent remarks by the U. S. Bureau of Standards* corrobate the foregoing: " The addition of so-called integral waterproofing compounds will not compensate for lean mixtures nor for poor materials, nor for poor workmanship in the fabrication of the concrete. Since in practice the inert integral compounds (acting simply as a void-filling material) are added in such small quantities they have very little or no effect on the impermeability of the concrete. If the same care be taken in making the concrete impermeable without the addition of water- proofing material, as is ordinarily taken when waterproofing materials are added, an impermeable concrete can be attained." The incorporation of any kind of integral waterproofing material into a mass of concrete will not materially prevent the formation of hair cracks or temperature cracks or cracking due to uneven settle- ment. Results with different materials will vary, but very few have proven entirely satisfactory. Neither can this system prevent seepage through day's work planes, and expansion joints, or joints between steel and concrete. Furthermore, this system of water- proofing, or rather the materials used in connection therewith, may reduce the strength of concrete and sometimes may even induce disintegration in the concrete. The integral waterproofing materials that will not do these things are, in fact, few, and their successful use requires so much care and labor that better results may often be obtained by the self-densified system of waterproofing, f In the light of present-day knowledge and experience with integral water- proofing compounds, their use and need are debatable on the basis of real efficiency. There are many cases, nevertheless, where any other system of waterproofing as well as the integral system might be used with equally good results, the selection under such cir- cumstances, being, of course, a comparison of costs. The integral system has, however an advantage always worthy of consideration, * Technologic Paper No. 3, p. 83. fThe author is able to say that several manufacturers of integral water- proofing materials have admitted this to him, but they asserted that these materials are worth their cost merely by acting as a factor of safety. It seems more probable, however, that these materials act more psychologically than as a safety factor. That is to say, workmen will probably feel more inclined to prolong the mixing and tamp more vigorously when told or shown that some- thing has been added, but which will really be effective only by such activity. SYSTEMS OF WATERPROOFING 60 namely, it requires no additional excavation or protective masonry, and the waterproofing operation proceeds with the construction, which is often a great advantage. In justice to some materials of this type that have apparently given satisfaction, it must be admitted that there is really great need for more extensive, and exhaustive practical tests, that is service tests, on this entire class of materials. INTEGRAL WATERPROOFING MATERIALS AND THEIR APPLICATION The types of materials above mentioned namely, po*wders, pastes and liquids, will now be considered in a more detailed manner. The many integral compounds appearing on the market are mostly of a water-repellent nature, but their compositions are seldom divulged, except those which are patented. The powders are usually of a white, floury consistency, and water-repellent. This property is imparted to them by the addition of some metallic stearate such as limesoap, which is of a fatty nature. The fineness of the powders gives them their void-filling properties, while those of a fatty nature act also as a lubricant for bringing into closer proximity the con- stituent materials of the concrete. The addition to the concrete mass of various amounts of hydrated lime also creates a dense mixture by the same procress. Use of Hydrated Lime. In regard to the addition of hydrated lime, experience has demonstrated that it serves to increase the plasticity and also to lubricate, as it were, the aggregate of the con- crete, resulting in a denser and more uniform mass. But the United States Bureau of Standards* states that the value of hydrated lime as a waterproofing medium is probably due to its void-filling prop- erties, and that the same results could be expected from any other finely ground inert material, such as sand or clay. While this is true, it is none the less an indisputable fact that hydrated lime acts in a greater measure as a lubricant, which the others would only do in a very limited way. Many proprietary compounds are composed mainly of finely ground sand and clay. By adding from 10 to 15 per cent of hydrated lime, the tendency of concrete to check and hair crack is materially reduced, as the lime absorbs and retains a large percentage of water and therefore holds the moisture in freshly poured concrete until the slower acting cement can utilize it. Mr. Sanford E. Thompson,! in a series of experiments on the * Technologic Paper No. 3. t American Society for Testing Materials, June, 1908. 70 WATERPROOFING ENGINEERING effects of hydrated lime in concrete, arrived at the figures in Table IV in regard to the effective proportions of hydrated lime for pro- ducing water-tight concrete. TABLE IV. PROPORTIONS OF HYDRATED LIME FOR IMPERVIOUS CONCRETE Portland Cement (Parts). Sand (Parts). Stone (Parts). Hydrated Lime (Per Cent). 1 2 4 8 1 2.5 4.5 12 1 3 5 16 The percentage of lime is in terms of weight of cement. The sand and stone are representative of average materials throughout the country. The coarser the sand, however, the more lime should be used. Lime paste occupies more than two times the bulk of paste made from an equal weight of Portland cement. Hence, by replacing the cement in mortar by about 15 per cent of hydrated lime, its density, and in consequence its strength and permeability are increased. But even with the addition of hydrated lime, the concrete materials must be graded, and 'the proper proportions of cement and hydrated lime used. If the concrete is poorly mixed or made with insufficient water, or improperly placed, or if joints are left unpro- tected, the structure will inevitably leak. The mixing must be thorough, sufficient water must be employed to give a " mushy " mixture so that it will settle into place with the least amount of ramming. Fully as important as the care in mixing is the bonding of one day's layer of concrete with the next; even small inter- ruptions of an hour on a hot day will materially injure the bond of the concrete. Use of Inert Fillers. Inert fillers vary greatly in durability and resistive properties, and should therefore be selected with con- siderable care. A governing property of all inert fillers is that they should not only be inert in the presence of the cement but also to atmospheric moisture and gases and percolating waters. Many fillers now used consist of clay, sand, lime and ordinary natural or Portland cement, this latter in a form exceedingly finer than ordinarily used, or in the form of " excess quantity " to make a rich mixture of the mass of mortar or concrete. SYSTEMS OF WATERPROOFING 71 The chemical composition of some inert powder fillers are given in Table V together with a comparative analysis of average Portland and natural cements. The first two are taken from a Technologic Paper of the United States Bureau of Standards* together with part of the following remarks: " Those materials which act as void fillers or increase the density of the concrete and are without any action on the cement and do not themselves change, are known as inert fillers. Included in this class TABLE V. ANALYSIS OF INERT FILLERS (CLAYS, SAND, FELDSPAR AND HYDRATED LIME) N. Y. Clay. Mo. Clay. Feldspar. Sand. Hydrated Lime. Silica 58 30 72.91 64 02 89 50 1 34 Alumina 16 85 15 01 19 38 2 36 45 Ferric oxide Manganese oxide 6.41 06 2.79 03 .70 trace 2.58 12 .13 Lime Magnesia 4.22 2.92 .59 .85 .87 33 1.37 57 46.90 32 19 Sulphuric anhydride (SO:.) . Sodium oxide Potassium oxide .12 .77 2.71 .12 .80 2 12 .10 2.52 11 76 .21 .26 70 4.02* 15 05f Water (105) .60 1.12 .06 .20 Ignition loss 7.00 3.81 54 2.35 99.96 100.15 100.28 100.22 100.08 * Carbon dioxide. t Total water. are hydrated dolomitic lime, clays, finely ground sand, and finely ground feldspar. Some of these may be partly changed in time when in the concrete. The hydrated lime may be partly carbonated, especially on the surface; the feldspar may decompose by the leaching out of the alkalies; the sand will change but very little, if composed of a high-grade quartz sand ; the clays will be very inert, although some theories have been brought forward which assume a very important role for clay when mixed with concrete ; this is to the effect that the colloids of the clay protect the calcium compounds from quick hydration, and consequently prevent increase in volume due to chemical action." However, reliable data show that the addition of clay to concrete or mortar decreases their permeability considerably and even increases their strength to a slight degree. But the use of clay as balanced against the addition of extra cement * Technologic Paper No. 3, p. 44. 72 WATERPROOFING ENGINEERING to accomplish the same results should be carefully considered, especially in the light of a comparison of costs. For, reasonably good clay must be used, and unless cheaply obtained the balance will invariably be in favor of the cement. Plain blue brick clay and pure white Georgia clay may be used with good results as inert void fillers. Use of Active Fillers. Active fillers consist of compounds which react with certain constituents of the cement, thus forming new compounds which are themselves inert and either barricade or fill up the voids. In most of these compounds on the market the active fillers form, but a small percentage of the compound proper as illustrated by the analysis in the first column of Table VI. " This compound was a white powder with a strong aromatic odor of Kauri resin. It was in fact partly a resinate of potash, which would be decomposed by the lime present to the corresponding lime rcsinate, which is comparatively insoluble. The great part of the compound is entirely inert, being china clay and hydrated lime. "As, however, in themselves these materials are not waterproofing, but become so only as a result of a series of reactions, it would be better to use the result of these reactions directly and not depend upon something that may not always take place either wholly or in part." Use of Proprietary Cements. Some proprietary cements are compounds made of Portland cement that has been altered by the addition of either stearates of lime, or soda and potash, sand, and other materials and specially treated until the mass becomes a water- repellent cement. Again, some waterproof cements are made by mixing about 5 per cent (by weight) of a lime-oil compound in clinker form, with Portland cement clinker and grinding them together. The powder formed is then used as ordinary cement, and results in a more or less dense concrete, not, however, in- dependent of the necessary care in mixing and placing. Another form of compound of this nature consists of fish-oil boiled in hydro- chloric acid, then mixed with burnt lime while slaking with water, the resulting product being a paste which dries and hardens as clinker. Another similar compound is made by combining a pow- dered resinate compound consisting of copal gum, hydrated lime and fine clay in proportion of 1 : 1 : 1 by weight with Portland cement, the use of which tends to make waterproof mortar or concrete. These compounds are also used for surface coatings as well as direct cements. When used as a direct cement, the lime-oil cement compounds depend for their impervious tendencies upon the formation of stearates of SYSTEMS OF WATERPROOFING 73 1. 6? O Tt< O GO O O 00 CO rH GO O5 O GO GO r l> t^ rH IO GO CO C^ O O3 C>q ^ O I I 8 SO O Tt< CO (N O CO GO O i> (M o ^ , s - 3 IsT- c? O O C^ GO GO CD Oi O (M CO CO rH O Tf GO CO O O rH CO 6 . COQO N g rH rH \ H B s j i 1.2 3^>> GO GO rH CD Q |3 & g.5 O T i os CO C^ CO | S CO CO ..- .. points directly over a joint or a crack in the sheathing boards, the next sheet should be shifted an inch or two so as to avoid the crack. Upon a flat roof the sheets are laid with the slope of the roof when the sheathing boards run that way. Beginning at the left, the first sheet is unrolled and placed so as to permit about 3 inches to extend up against the fire wall, or in the event that the roofing is turned over sheathing boards at the side, 1 or 2 inches should be allowed for this purpose, and from 1J to 2 inches at the eaves or end'^of the sheet. This sheet must be carefully adjusted and flattened into! position, folding the sheet carefully where it projects against the ifire wall so as to make a good corner without breaking the felt. It is temporarily secured in place by driving a few nails along its edg and end; then the next sheet is unrolled, allowing it to overlap at (east 2 inches, being careful to obtain a uniform lap along the entire seam. After this second sheet is carefully adjusted and flattened out, it should be nailed directly over the 2-inch lap, placing the nails within J inch of its edge. This is repeated until the entire roof is covered. Making watertight flashings against fire walls, is equally as important as making watertight joints between plies and laps in the! various roofing materials. This is discussed in the following article. i ROOF FLASHINGS 'An important part of the construction of roofs and roof parapet walls on large brick or concrete buildings is the flashing. Flashing may be defined as a piece of metal or waterproof material used to keep water from penetrating the joints principally between a fire wall or projection through the roof of a building or other structure. Its 'efficient location and application as well as the selection of the best material are matters that require careful study. For general work most roofers can supply and apply flashings meeting all re- quirements. The vital part of a brick parapet wall is the inner side, which heretofore was made up of common brick laid up in ordinary lime mortar. As a result, and owing to the freezing of the brick above the roof flashing due to saturation from snow or rain many brick parapet walls, after a few years became a crumbling mass. In consequence the flashing became loosened and water percolated through the joints to the detriment of the interior, To avoid the IMPERVIOUS ROOFING 117 above condition it is now the practice to build the inner side of the brick parapets of hard burned vitrified brick laid up. in cement mortar and covering the top with a waterproof Doping;-, ; In addi- tion to this the roofing material is sometimes carried": up to the under side of the coping. But a common procedure .Is. ' to take one or more strips of felt or ready roofing about 12 inches wide, folded in the center and fitted into angles at fire walls, chimneys, etc., so that 6 inches project up these surfaces and 6 inches lap over the roofing. These strips are fastened (if more than one is used as on composition roofs) with a row of nails at the upper edge of the upper strip by driving them into the mortar joints between the bricks, and securing the lower edges (if ready roofing is being applied) with a row of nails applied similar to an ordinary lap, or by mopping with pitch or asphalt (if composition roofing is applied) and com- pletely coating the surface of the flashing strip as is ordinarily done on the roofing proper. All flashings on brick walls, etc., should be counter flashed with metal so as to prevent water from eventually working in behind them. These counter flashings must be thoroughly secured in a mortar joint above the roof flashings and turned down over the seam for at least 4 inches. For buildings subjected to gases and fumes, saturated felt properly coated with good asphalt or pitch preparations will give good results. For buildings located outside of industrial centers, non-corrosive metal flashings give very good results. A very efficient means of fastening both the flashing and counter flashing is shown in detail (applicable both for com- position and ready roofing at parapets) in Fig. 36. This detail, recommended as good practice by the American Railway Engineering Association,* makes use of a 2- by 4-inch timber with one edge beveled, laid continuous in the parapet at the proper height in place of a stretcher course of brick. This serves as a nailing strip for a light wooden strip holding the flashing and counter flashing in place. After placing the flashing the slot is completely sealed up with cement grout or roofing cement. For the proper flashing of concrete parapet walls the detail shown in Fig. 36 can be recommended. * A 2- by 4-inch piece of lumber is ripped on the diagonal as shown and then placed in the forms at the desired height, the upper strip being securely nailed thereto, so as to insure its removal when forms are taken down, while the lower piece is just tacked to forms (from outside) with wires or nails driven into it as shown to anchor it to the concrete. The flashing and counter flashing are then placed in the same manner as for brick walls. * Concrete. Vol. 9, No. 6, December, 1916, p. 197. WATERPROOFING ENGINEERING An ingenious and inexpensive flashing is shown in Fig. 37. The metal lock referred to in the diagram is of galvanized sheet iron, and acts as the backbone for the flashing, which may be made of ordinary felt or strips of prepared-roofing felt, these often being substituted for the more expensive all-metal flashings. 2 'x 4 (Continuous 1 ) Seal of Cement Grout or Roofing Cement BRICK PARAPET A CONCRETE PARAPET B FIG. 36. Flashing Details. ROOF CUTTERS The function of impervious roofing is to shed the rainwater so that none finds entrance into the building. On small and unim- portant structures, rainwater is allowed to drip off the eaves, often discoloring the walls. On most structures, however, both large and small, provision is made for taking care of the drip by providing gutters directly under the eaves, or other roof plane, and in the valleys of the roof. The most modern practice is to slope the roofs of buildings so as to provide drainage in the direction of the center of the structure, where the gutters and conductors are arranged for easy access. This arrangement avoids marring the architectural effect of the facade. Fig. 38 shows typical arrangements of metal gutters and conductors, for mill and factory buildings. IMPERVIOUS ROOFING 119 Portion of lock before hammered Metal lock is hammered to ready-roofing flashing-strip* gripping same by means of clinch holes in the lock Joints are filled with cement mortar or flexible cement. Mopped underneath with pitch or asphalt. FIG. 37. Showing Method of Using Felt in Place of Metal Flashings. (Metal Lock Illustrated is Patented.) Adjustable ffanger every FIG. 38. Eave and Valley Gutters of Galvanized Iron or Steel. (American Bridge Co.'s Standards.) 120 WATERPROOFING ENGINEERING Gutters should be sloped not less than 1 inch in 15 feet, and if made of sheet iron, or steel, should preferably be galvanized than tinned because the latter variety corrodes more easily around an abrasion or other slight damage. The gutters and leaders, or con- ductors, made of these metals should be of No. 22 to 20 gauge (18 to 22 ounces per square foot). On the better class of structures, gutters and conductors are usually made of copper, in which case the metal used varies in weight, from 14 to 20 ounces per square foot. Hanging gutters are frequently made of considerable length; there- fore they should be strongly built, as otherwise they are liable to deflect from a uniform grade. Simple and inexpensive gutters are often made by fastening a strip of wood, of appropriate size, close to the end of the eave of the roof and sloping towards the conductor. This strip runs along the entire length of the eave, and is covered by the material used for the roofing, or by sheet metal. This practice, however, is mainly resorted to on low buildings, such as mill buildings and small-town railroad stations. FUNCTIONAL ROOFINGS Definition, Use and Varieties cf Functional Roofings. Functional roofings consist of such materials as both waterproof and roof the uppermost part of a structure; that is, they are compositive and include all those not covered by the previous types of roofings. Most of the functional roofings are of recent origin and have a limited use because they are usually adapted to special types or temporary structures. They are for the most part though, efficient and often inexpensive. The following are examples of functional roofings: Corrugated or crimped galvanized sheet iron (see Fig. 39) and asbestos-covered corrugated sheet iron (see Fig. 40). These are often used for the roofs of freight cars and small mill buildings; also metal shingles, which have a limited use on railroad structures. In general, however, steel or impure iron materials are avoided, especially on important structures, even though these materials are protected, because of the necessity of frequent repair or renewals. The structural-composite roofing shown in Fig. 41 is serviceable for train sheds, depots, and large mill buildings. Heavy cotton canvas, sometimes treated with a preservative, but always painted, is extensively used as roofing for freight and passenger railroad cars and on decks of ferry boats. Glass roofings, for which there are many methods of making watertight joints (two of which are IMPERVIOUS ROOFING 121 11 " " 11 ,. " ,. " " FIG. 39. Corrugated Galvanized-iron Roofing, Showing Method of Lapping and Flashing. FIG. 40. Asbestos-covered Corrugated Roofing. 122 WATERPROOFING ENGINEERING FIG. 41. Structural-composite Roofing. [ Purlin Clip Cushion "^ h^ \ \ /Condensation i)\ / Gutter -Insulation and Rust Proofing Purlin Clip | FIG. 42. Two Types of Watertight Joints in Puttyless Glass Roofing. (Patented.) IMPERVIOUS ROOFING 123 shown in Fig. 42) are well-adapted for depots and general skylights of -buildings; also for roofs of buildings used in the production of motion pictures. Roofs of many factory buildings and all concrete buildings are made either of reinforced concrete or, to insure better watertightness, have an integral waterproofing compound added to the concrete. The method of applying functional roofings depends on the material and also somewhat on the structure. Sheet and corrugated galvanized iron are usually nailed down to the purlins and lapped both lengthwise and crosswise as shown in Fig. 43, A. Sometimes FIG. 43. A. Methods of Nailing Down Corrugated Sheet Iron on Roofs and Sidings. B. Methods of Applying Sheet or Corrugated Roofing to Roof Framework. small iron cleats are riveted to the sheets which hook on to angle irons screwed on to the purlins or roof frame work. Fig. 43, B, shows several methods in common use. The former method pro- duces a more durable and watertight roof. . The slab type of functional roofing is usually made so as to lap over each other and fit into prepared grooves. The joints are usually made watertight with an adhesive, elastic compound. A roof built of concrete blocks or blocks of any other material will not of itself be watertight because of the many joints; such roofs must first be waterproofed usually with a membranous roofing material, hence these materials cannot be classed as functional roofings. CHAPTER IV WATERPROOFING EXPANSION JOINTS IN MASONRY Function and Properties of Expansion Joints. Expansion joints constitute one of the basic causes contributing to the difficulty of making masonry structures watertight. When masonry is to be waterproofed its expansion joints must be so made that water cannot pass through them. This is usually accomplished either by some form of tongue and groove, by a bent cutoff plate, by gaskets, and so forth, in endless variety. Designers usually include some form of bitumen or other sticky, plastic material as a joint filler. To devise a joint that will remain tight under all conditions of weather and stress is exceedingly difficult. Most failures of water- proofing are due to the lack of joints, to joints not placed where the tensile stress is large, to narrow joints, or to joints which do not remain watertight. In a great many cases if an adequate number of good watertight joints were provided no other waterproofing would be required. Concrete and other masonry can nearly always be made as impervious as necessary between cracks, and therefore the waterproofing of a structure is often a question of waterproofing its joints. Hence, we shall investigate, (1) the methods used for the proper provision for expansion and contraction in concrete or other masonry; and (2) the methods used for proper waterproofing of the joints. Expansion joints are used in structures to allow the masonry to expand and contract freely with changing temperature, and to per- mit other necessary, small, internal movements and readjustments. Expansion joints are, in fact, simply cracks built into the masonry to anticipate or take the place of the internal cracks and breaks. A sufficient number of these joints must be provided to avoid dis- figuring the masonry with unsightly cracks (see Fig. 124). The following instance demonstrates the commonest way that cracks occur in masonry. Structural materials have a varying coefficient of expansion* (see Table XXX). * The coefficient of expansion for. any material is the factor which expresses the change per unit of length for each degree of temperature. 124 WATERPROOFING EXPANSION JOINTS IN MASONRY 125 The coefficient of expansion for concrete is variously assumed as .0000055 or .0000065 per deg. Fahr. (about | inch in 100 feet for each 15 deg. Fahr.). These coefficients vary somewhat with different proportions and kinds of aggregate in the concrete. Assum- ing for concrete a modulus of elasticity of 2,000,000 pounds per square inch and an ultimate tensile strength of 200 pounds per square inch, a distortion, in tension, of 0.0001 inch will fracture it.* Fifteen degrees Fahr. drop in temperature produces this change in length and is thus just sufficient to break restrained concrete. Monolithic Construction Obviates Expansion Joints. To avoid the use of expansion joints, small structures are often built as mono- liths for which the waterproofing is fairly simple. Larger structures can be built monolithic by imbedding sufficient steel in the concrete so that the concrete is not stressed beyond its breaking strength. The elimination of joints by this method may be carried a step further. Reinforcing metal can be placed the whole length of a structure of any size or of a structure whose ends are restrained. But in this case the function of the steel is quite different from ordinary reinforcing steel. Fifteen degrees drop in temperature will break the concrete as if the steel was not present. But the intro- duction of the steel merely causes the cracks to be smaller and closer together. Steel has about the same coefficient of expansion as concrete. But the ratio of ultimate tensile strength to modulus of elasticity is so much greater with steel than with concrete that, while concrete is broken by a 15 deg. Fahr. drop in temperature, a drop of 100 degrees only stresses steel to its safe working stress, a drop of 175 degrees to its yield point, and no temperature change whatever is able to break it. A moderate amount of steel makes the cracks so small and close together that they are unnoticeable. The actual quantity of steel, which can be readily computed, varies between .1 per cent and .3 per cent of the cross-sectional area of the concrete depending on climate and local conditions, as, for instance, whether the structure is above or below ground. None the less it must be borne in mind that the concrete is fractured and that therefore water will find its way through, particularly if under a head. The total cross-section of the cracks will be about the same in both cases, but the capillary and fluid friction through the mass will considerably reduce the permeability of the concrete, and eventually these minute cracks may be closed up with silt, thus making the structure completely watertight. * Modulus of elasticity equals stress divided by deformation; using these values the deformation is 0.0001. 126 WATERPROOFING ENGINEERING Design and Spacing of Expansion Joints. The width of a joint controls the longitudinal movement of each section, and, hence, controls the movement of the entire structure. Therefore expansion joints should be large enough to accommodate any movement that may occur and spaced sufficiently close together to eliminate all other cracks or joints. In other words, the joints must be so spaced that under all conditions of temperature change, loading, vibration, or foundation settlement, the masonry between the joints will be a single monolith. The proper location and design of these joints require forethought, experience and good judgment. To design a joint, the change in length is computed for the tem- perature variation of the particular climate. This is increased as needed to allow for other movements, plus a small amount as a fac- tor of safety. The spacing of the joints is determined by computing the frictional resistance to movement between the masonry surfaces. The joints must be so close together that the stress resulting from this friction is within the safe tensile strength of the masonry. Stresses due to other causes must of course be computed and combined with the friction stress. Joints may be located at intervals of from 25 to 50 feet, although under favorable conditions and sufficient reinforcement, larger sections may be used. But the larger the section between joints, the wider should the joint be made. For restrained structures and large gravity retaining walls, the maximum distance that joints should be spaced is 50 feet. Concrete walls which are less than 3 or 4 feet in thickness, and subject to about 60 deg. Fahr. seasonal change of temperature, should have joints spaced about 30 feet apart. Joints in Brick Masonry. Expansion joints in brick masonry are rarely employed, but the joints between the bricks require care- ful attention where impervious walls are necessary, as for instance, in residences. The mortar in the joints of brick masonry is usually deficient in density and hence is quite absorbent and more or less permeable. Often for the sake of enhancing the appearance of a residence the mortar is raked out of the joints for a depth varying between | and 1 inch and left so. This is poor practice because very little mortar may remain near the front face of the brick to prevent the percolation of water especially when aided by a driving rain. This often happens, resulting in damp and wet interiors. Where it is proposed to use this type of joint in the masonry, then, to make these joints imper- vious, half the raked-out space should be filled with a pointing mortar. The pointing material may be either neat cement or mortar WATERPROOFING EXPANSION JOINTS IN MASONRY 127 composed of Portland cement and sand in equal proportions, mixed with enough water to form a stiff paste. This paste should be tamped in with a metal calking tool and the joint facings can then be finished according to one of the pointings shown in Fig. 44. Where this practice is not resorted to, i.e., where neither raking nor special joint mortar are employed, and where dry and damp- proof interiors are desired (assuming that the best grade of bricks were used) then the mortar joint' proper, madeas the work progressed, should also be pointed as illustrated. The Slip-tongue and Plane-of-weak-bond Joints. The types of expansion joints used in practice are almost as varied as the types of masonry structures built nowadays. The simplest expansion joint for concrete dams, walls, etc., is a plane of weak bond in the structure, FLUSH JOINT STRUCK JOINT WEATHER JOINT FIG. 44. Types of Mortar Joints Used for Appearance and Utility. made by building one section first and coating it with bitumen or other compound, or nailing to it one or more plies of treated felt, sometimes bonded with bitumen, against which the concrete of the second section is poured. That it is necessary to create a plane of weak bond in the structure, by interposing some form of coating or sheeting between the joints of all sections, is evident from the fact that the separation at the joints is not otherwise uniformly perfect. When joints are formed without interposing any sheetings or other separating material, then by pouring one section after the adjoining section has set, no adhesion of any large amount would be expected under these con- ditions; yet it often happens that there is a strong enough bond to break through solid concrete alongside the joint. This is evidenced by the many meandering cracks (other than shrinkage cracks) often seen close to and paralleling the V-groove formed in the face of concrete walls at joints, 128 WATERPROOFING ENGINEERING Another phase of the joint problem worth noting is the protection of horizontal joints. In the construction of concrete walls, abut- ments, etc., almost sole attention is given to vertical expansion joints and their protection against the seepage of water through them. Little if any real attention is paid to horizontal joints, and yet it is these joints that are mostly responsible for discoloration (see Fig. 2) and equally responsible for leakage in these and other structures. Whether the horizontal joint be a days- work joint or a construction joint, its existence is a source of danger to the unity of the structure from the waterproofing point of view, and should be cared for as effectively as vertical joints. Fig. 45 shows an effective Lap Joint- Strips joined by heatin faces Expansion Joint, non-flowing filler B SECTION A-A Construction Joints ,,. A ':?'- 1 ^ Asphalt Strip Baffle^ ^Construction Joints * x M x 8' 1 ^^Viscous Bituminous Compound j: r -r.-;^:^- :^-^:t-- :-:?*: :*.-: SECTION B-B (COMPLETED) WALL ""Joint Coated with Paraffine FIG. 45. Location of Horizontal Baffle Joints in Walls and Tanks. method of waterproofing horizontal joints. Its efficiency is some- times doubtful because the slip tongue, which is generally made of sheet iron, and though sometimes painted with a preserving com- pound, too often corrodes and vitiates its function. What should be used as a slip tongue to avoid such defects is a non-corrosive material and such may be made of tough elastic asphalt strips similar to the precast expansion joint fillers used in concrete road construction. Fig. 48 shows such a scheme of protecting horizontal joints in which the barrier is placed on the finished concrete in the form of a strip, before the new concrete is deposited. Illustrations of Expansion Joints. One requisite for all forms of expansion joints is that they be so constructed as to retain the WATERPROOFING EXPANSION JOINTS IN MASONRY 129 joint filler (which alone waterproofs the joints) as long as the struc- ture lasts. A second requisite is that the joint filler itself retain its properties, and last equally as long, or allow of replacement at definite intervals. The first requisite will be well provided for by adhering to the basic type of joints shown in Fig. 46, modified, of course, to conform to any special requirement. The second requisite will be satisfied by any material which does not lose its " body " or substantial character, adhesiveness and elasticity, at least not rapidly, and is not affected by water. Such compounds are dis- cussed further on in this chapter. Front of Walk Slab ^ M :':^x.l#:V.v-:i-.v rr~'. . '*-'* ' *V- ' ' /.:-V::v.:.:d. : ..ij.;. : VERTICAL EXPANSION JOINTS x-Joint Filler Joint Filler 1 Stiiieifc?d : ^ah?i ; D E HORIZONTAL EXPANSION JOINTS FIG. 46. Basic Types of Waterproofed Expansion Joints. Fig. 47 (A, B, C and D) is taken from a report by the Committee on Buildings and Structures of the American Electrical Railway Engineers Association. These joints have several interesting features which are evident and self-explanatory. Fig. 48 illustrates a method of waterproofing horizontal and vertical joints in concrete walls; the former by means of gaskets or strips of fabric thickly coated with a bituminous material ; the latter by means of rolls of the same material fitted in a prepared groove of one section and surrounded by the concrete as poured for the next 130 WATERPROOFING ENGINEERING J " '"4 4. <-12" i !i ^ ELEVATION A, EXPANSION JOINT FOR RETAINING WALL" A f " Separation made! by insertion of waterproofing material . Stone laid .dry packed /against wall 1 xfor 3'0'at each expansion joint and weep hole. J. EXPANSION JOINT FOR ARCHED ROOF OR SIDE WALL Top of Platform G. EXPANSION JOINT FOR ARCH OR RETAINING WALL D. EXPANSION JOINT FOR PLATFORM FIG. 47. Typical Forms of Waterproofed Expansion Joints Used for Various Structures. WATERPROOFING EXPANSION JOINTS IN MASONRY 131 section, with the rest of the joint between sections filled with several plies of treated felt. It is possible to make very efficient expansion joints in this manner, provided the compound used for treating the fabric, of which the gaskets and rolls are made, remains tacky and Back of Wall \ &ET -Flap id - ^ yl Horizontal Joint/ Filler. 2 Layers ^ v- I ^Vertical Joint Filler, Tight Roll, 3 Dia. r h 3 Ply Treated Felt SECTION A-A FIG. 48. Horizontal Waterproof Baffle, and Vertical Expansion Joint and Joint Filler Used on Concrete Retaining Wall of the Brighton Beach Line, B.R.T. Railroad System, Brooklyn, New York. adheres to the concrete when set, and elastic, so that it " gives " when contraction and expansion take place. Fig. 49 shows a horizontal joint for a concrete floor. This joint is waterproofed by means of a copper V-joint anchored and filled with a joint roll, consisting of treated fabric wound tightly on itself and covered with some tenacious and elastic compound, which when 132 WATERPROOFING ENGINEERING the joint contracts, forms a bulb upward, and on expansion forms a groove. But this operation is only possible when the joint filler adheres tenaciously to the sides of the joint. iiSHiHl FIG. 49. Type of Waterproofed Expansion Joint Used on Public Service Railway Terminal, Newark, N. J. Fig. 50 is a form of expansion joint advocated for solid bridge floors, and patented by Mr. A. H. Rhett, Engineer. Fig. 51 (A and B) is from the Waterproofing Specifications of the Chicago, Milwaukee and St. Paul Railway, and shows their method of waterproofing j.-jy.;-:c--:ii:-'^:-.:p.-:w-- j [\-~.-m\o > o *v:-X2&-B-ff.W.&Wt^. FIG. 50. Waterproofed Expansion Joint for Solid Floor Bridge. (Patented.) bridge floor expansion joints. This method consists in applying two continuous strips of treated felt, 36 inches wide, over the expan- sion joints, being careful to see that no bitumen gets between or under the two strips of treated felt. Then the top strip is mopped with hot bitumen and the waterproofing proper carried over the top of the felt as if no joint existed. WATERPROOFING EXPANSION JOINTS IN MASONRY 133 The joint shown in Fig. 52, A, is a vertical square or rectangular recess filled with plastic clay. The clay must be of the best quality, placed while wet and rammed absolutely solid into place, otherwise it will not cohere into a unit mass. Fig. 52, B, shows tne rectangular and triangular tongue-and-groove types of joints commonly used for small masonry bridges and abutments, parapet walls and retain- 2 Layers of Tar Paper SECTION OF EXPANSION-JOINT ON LEVEL SURFACE A Expanded Metal- Round off corners of slab 2 Layers of Tar Paper SECTION OF EXPANSION-JOINT AT OFFSET IN WATERPROOFING SURFACE B FIG. 51. "Unfilled" Type of Waterproofed Expansion Joint. ing walls. They form merely a weak bond in the structure, but permit lateral movement and so prevent disalignment. However, unless some barrier, as a bituminous sheet or membrane, is inter- posed, water will readily seep through these joints. Fig. 53 shows a reinforced tongue-and-groove joint successfully used on the Compton Hill Reservoir, St. Louis, Missouri.* The * Engineering News, December 23, 1915, Vol. 74. 134 WATERPROOFING ENGINEERING joint was filled with treated felt and pitch binder as each section was built up. Fig. 54 shows an all-adaptable form of joint waterproofed with a soft asphalt contained in a copper bulb the imbedded portion of which is perforated so as to bond more securely. Fig. 123 is an efficient form of joint used by the Delaware, Lackawanna & Western R. R. on two of its viaducts. Cutoffs in Expansion Joints. Water should not be allowed to enter expansion joints; but if this be inevitable, then it is best to use some form of cutoff, near one face of the structure, and to provide proper drainage within the structure. Copper, tin, galvanized iron, lead and zinc sheeting are often used as cutoffs in expansion joints, A Clay Pi IS fe^v lliSil - ^| ^-M*^*^K ; vV ' } -."^--^- : ' FIG. 52. A. Rectangular Recess in Expansion Joint, Filled with Plastic Clay. B. Rectangular and Triangular Tongue-and-groove Expansion Joints. and all serve their purpose very well, but the copper sheeting best of all. There are two types of cutoffs, known as the internal and exter- nal. One of the best illustrations of modern practice showing the use of the internal type of cutoff is in the expansion joints of the Kensico Dam on the Catskill Aqueduct of New York City. The expansion joints in this dam contain a strip of copper placed across each joint near the upstream face to cut off leakage (see Fig. 55, B). This cutoff was constructed in the following manner: A portion of the strip was placed in a groove in the vertical face of the masonry forming one side of the expansion joint, and sur- rounded with concrete or mortar, allowing the remainder of the strip to project, as shown in detail in Fig. 55, A. WATERPROOFING EXPANSION JOINTS IN MASONRY 135 o'.;;,;. :'::: O % 15 c. to c. /./'.'? -."Expansion Joint r\ ^. H Bent Bars .'-.- 12 "c. toe. ^ FIG. 53. Detail of Reinforced Expansion Joint for Retaining Walls. Sidewalk or Road way Slab \ ^S^'WSttt v^VW^f^tei..,. :.: - ::.'. : : .'.' ip'orta pn.'<^'.-. ': <{ : '&/.:i&y$$&ft?ty&s. : : .'.':' : .:;.; .':j>:.-.'-';'- : -'-" '.'.":' \ ^^ ; ^::-'/-^:&':- : -:& P13lf ; ^ lR ^itfj^y^:!:. FIG. 54. Type of Waterproofed Expansion Joint Used on the Brooklyn-Brighton Viaduct, Cleveland, Ohio. 136 WATERPROOFING ENGINEERING WATERPROOFING EXPANSION JOINTS IN MASONRY 137 After the concrete or mortar in the groove had set, the central part of the projecting strip and the portions of the vertical faces of the masonry against which it rests were coated with hot paraffin or other suitable substance to prevent the adhesion of the strip to the concrete where it crosses the expansion joint. Concrete was then placed and carefully rammed around the projecting strip on the other side of the joint, care being taken to thoroughly clean the uncoated portion of the strip before placing the concrete. The strips were built up in sections, riveted together with copper rivets. The operation of this cutoff is as follows: As the masonry contracts, the expansion joint is, of course, enlarged. Water enter- ing at D (Fig. 55, C) will proceed as far as the junction of the copper strip E and the masonry. From there the water cannot get around Exterior of Pipe Wall'" FIG. 56. Expansion Joint with Internal Cut-off Used in Reinforced Concrete Waterpipe. (Patented.) to the other junction at F. Hence, it remains there and freezes when cold weather sets in. The effect of this freezing and the con- sequent thawing is cumulative upon the structure in that when ice forms the water expands, exerting a force in the same direction as the contraction of the masonry, caused by the lowering of the temperature. On the other hand, when thawing sets in the mobility of the water returns and the masonry expands unimpeded. The copper strip being placed near the upstream face keeps the rest of the joint practically dry. The internal cutoff is not limited only to large and massive struc- tures, but may be and has been used very successfully on reinforced concrete pipes for conveying water even under pressure. These pipes are usually made in small lengths, 3 to 10 feet, of scientifically graded aggregate mixed in about the following proportions, 1 : 1J : 2J. The connection between lengths is made in the form of an expansion joint, such as shown in Fig. 56, which is patented. This expansion 138 WATERPROOFING ENGINEERING joint has an internal cutoff in the form of a strip of soft copper cast in the spigot end and passing clear around the pipe, being crimped as shown to permit the longitudinal movement of the sections. The other end is set in mortar rammed into the joint from the inside, and protected with a coat of neat cement, as shown. The joints are made free to open and close by the application to the face of the spigots of a bituminous paint. -Asphalt Block Paving Steel Plate Tar Paper. Vitrified Pipe if required' -Vitrified Pipe FIG. 57. Detail of Expansion Joint for Bridge Floor. An expansion joint in which the water is not only prevented from entering, but is quickly drained off if it should enter, is shown in Fig. 57. This was also used on work connected with the Catskill Aqueduct in New York City. Fig. 58 shows another joint of this type (sliding expansion joint) unique in its design, adapted to and used on the road slabs and sidewalks of the concrete arch bridge in City, Mo.* A similar joint, modified so that sliding is * Engineering Record, Vol. 75, No. 3, January 20, 1907, p. 109. WATERPROOFING EXPANSION JOINTS IN MASONRY 139 obtained by means of short pieces of old rails imbedded in the base of slabs and top of piers and abutments, was used on a double- track concrete railroad bridge over the Oka w River in Illinois.* The external cutoff is much used by railroad engineers for retain- ing walls and deserves a wider application than it at present enjoys. This cutoff usually consists of a fold formed by laying the membrane 1 Layer Paraffin Treated Felt, between 2 Layers of Tarred Felt Drainage Groove l"wlde, 2 deep, Full Length ol Plates ROAD SUB EXPANSION JOINT Paint under surface with hot asphalt x %' Bar 2Vc. to c. --Drainage Groove SIDEWALK EXPANSION JOINT FIG. 58. Road Slab and Sidewalk Waterproofed Expansion Joints Used in Floor of Concrete Arch Bridge over the Blue River, Swope Park, Kansas City, Mo. of whatever material is being used for the waterproofing, over a 1-inch pipe at the joint in the concrete to allow for the expansion in the structure. The pipe is removed after the mat is completed. This mat is then covered with a protective coat of mortar or concrete, and sometimes with mastic. The external cutoff type of expansion >int shown in Fig. 59 was designed by H. J. Finebaum, engineer, * Engineering News-Record, Vol. 80, No. 8, February 21, 1918. 140 WATERPROOFING ENGINEERING and used on the new Hill-to-Hill bridge at Bethlehem, Penn.* It consists of two pieces of copper held in the concrete by lugs made by bending back the split ends of each piece and placed on each side of the joint with one end projecting through a groove in the con- crete beyond the inside face of the wall. These protruding ends are then bent over to hold a copper flashing piece across the joint between the sections of the wall. The flashing and straps are then No. It (Am. Gage) Soft-rolled Copper Straps, spaced. 2 ft. c. to BolU PUL SPECIMEN On No. 8-12 PUHC SPECIMEN FIG. 106. Types of Permeability Specimens. one exception noted above. Similar tests made on f-inch plain cement mortar of proportions 1 : 1J applied to the concrete (Fig. 105, C), proved two facts: (1) that plain mortar can be made rea- TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 227 sonably watertight; (2) that some of the above compounds, such as the foreign ingredients added to the mortar coating, are also reasonably effective and warrant their use under certain conditions. Results of Permeability Tests on Plain Concrete. Still another method for testing the permeability of mortar and concrete, though only occasionally used, is worth noting. In an elaborate series of permeability tests,* in which machine-mixed concrete and large specimens having a prescribed volume of concrete were used without FIG. 107. Longitudinal Sections of "PU" and "PUHC" Permeability Specimens. any waterproofing added to them, many valuable facts are made patent. The forms of specimens are shown in Figs. 106 and 107. In molding these test pieces, both mortar shell and concrete core were cast at the same time. The area of the core is 1 square foot, hence the leakages read were in terms of this unit. The results of these permeability tests, made on 294 gravel- concrete specimens, agree very well with similar tests made by other experimenters. Of the above number 88 were of 1 : 1^ : 3 and 67 of 1:2:4 proportions by volume; 98 were of 1:3:9 proportions by weight. * Journal of the Western Society of Engineers, November, 1914, Vol. 19, No. 9. 228 WATERPROOFING ENGINEERING None of the coricretes tested was absolutely watertight if we consider continuous flow into the specimen as proof of permeability, but the majority of mixes were so impervious that no visible evidence of flow appeared. For most purposes such mixes can be considered watertight. The visibility of dampness on the bottom of the specimens increased with the humidity of the air and the non-homogeneity of the concrete. The minimum rate of flow for which leakage was indi- cated was 0.00011 gallon (approximately .42 c.c.) per square foot per hour. In tests of nearly all of the properly made mixes of 1 : 2| : 4J proportions, or richer, the rate of flow for a fifty-hour period was less than 0.0001 gallon (approximately .38 c.c.) per square foot per hour under a pressure of 40 pounds per square inch. Through increasing the fineness of the cement a reduction in the rate of flow and a considerable increase in the strength of a 1:3:6 mix were secured. By grading the sand and gravel in accordance with Fuller's curve it was possible to obtain practically watertight concrete of 1:3:6 proportions under pressures less than 40 pounds per square inch. To secure such results, however, requires great care and careful supervision in mixing, in determining the proper consistency, in placing, and in curing the concrete. In the proportioning of such materials as these, volumetric analysis coupled with a determination of the density and air voids yields very valuable information concerning the best proportions of sand and gravel for a given proportion of cement. If proportions must be selected arbitrarily, a 1 : 1J : 3 mix, by volume, is very impervious. It should be remembered, however, that the volume changes in rich mixtures due to alternate wetting and drying are much greater than for lean mixtures. Consequently due attention must be given to the provision of expansion joints and reinforce- ment in structures made of rich mixtures. The use of the proper amount of water necessary to produce a medium or mushy consistency is one of the most important con- ditions in securing impervious concrete, especially when lean mix- tures are used. Dry mixtures cannot be sufficiently compacted in the molds and are more difficult to cure properly than the mushy mixtures. Although the use of a wet consistency does not materially affect the imperviousness of very rich mixes, such as 1 : 1J : 3, it greatly increases the flow through a lean mix. For lean mixes made from damp sand, it seems advisable to mix TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 233 H- T-H O 1-1 1-1 i-i d 4- d d dddd dddd dddd dddd O O5 Tf Ci i I t>- 1C 00 Tj< ^ r^Tjico^ CO'(N'COCO' 10 00 iOO'^t l OOOOOOOO QO 00 00 Q0 I I 81 S| S TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 233 &m D. a-!li M 2 s 6 1 s * CO b- (N C^ O^ "^ *^ rH O jir-( 88 $ o d 3 1 o S CJ ^ |M CD .s &L &0 ^X c . M "^v a ^sO lef IB! ^s Jfe 'S ^ 5 BI 2O'S ^J3 l gg eg * fe . i 1 H Soft [ 92 106 118 132 33.4 31.5 5.79 6.55 102 117 138 150 31.5 34.3 9.22 10.10 Medium < 121 130 154 162 31.4 33.6 8.34 44.4 145 138 180 170 32.9 35.4 11.50 4.97 Hard 136 154 178 194 32.7 34.9 3.24 7.47 150 168 188 208 33.5 36.3 5.68 10.85 Straight-run coal-tar pitch and raw linseed oil of good quality were used in this test. The melting-point was determined by the Cube-in- water Method. This test discloses the fact that prolonged heating of pitch even when mixed with linseed oil, is injurious, as shown by the amount of oil evaporated, and the great rise in melting-point. Hence it is imperative not to subject this coating material to continuous heat, but if this becomes unavoidable, the tank must be frequently replenished with new material. 238 WATERPROOFING ENGINEERING Flowing and Bonding Properties of Pitch Containing Small Quantities of Asphalt or Linseed Oil. To obviate the danger and nuisance of using hot coal-tar pitch for waterproofing by the mem- brane method under compressed air, tests were made to determine the flowing and bonding properties of different melting-point pitches mixed with either 5 per cent of raw linseed oil or 5 per cent of dif- ferent melting-point asphalts. These additions were made in an effort to increase the fluidity of the pitch somewhat without reducing its " substantiality " and to avoid the necessity of heating it on the work during application. These additions had the desirable effect of lowering the melting-point of the pitch about 10 deg. Fahr. (5.5 deg. Cent.) without increasing its hardness. Four pitches were tested having the following melting-points: 75, 85, 95 and 105 deg. Fahr. (24, 29.5, 35 and 40.5 deg. Cent, respec- tively). (Cube-in-water Method.) The three asphalts used to make the 5 per cent additions had the following melting-points: 107, 154 and 182 deg. Fahr. (42, 68 and 83 deg. Cent.). (Cube-in-water Method.) The oil used was a good quality raw linseed oil. Sixteen samples of pitch were weighed out in pint cans and each set of four of equal melting-point received an addition of 5 per cent by weight of one of the three different asphalts or the oil. These were then heated,' thoroughly stirred, and allowed to cool to about 75 deg. Fahr. (24 deg. Cent.) which was approximately the tem- perature of the compressed air chamber under about 21 pounds pressure. On reaching this temperature each sample was troweled onto the surface of pieces of treated fabric until a 3-ply membrane was built up on planed boards as a ground work. None of the pitches was fluid enough to be mopped on, hence the troweling. The boards were then inclined at an angle of 45 degrees for seventy- two hours to compare the relative amount of sliding of each mem- brane. Table XIV shows the results obtained from the various mixes. Specimens Nos. 2 and 5 appear to be best suited for the purpose, because at the temperature under which they will be used, they are both more substantial and v/orkable than the others. Finally, since the admixture of linseed oil greatly increases the cost of the product, the one (No. 5) with an admixture of asphalt is to be pre- ferred. Effect of Asbestos Filler on the Physical Properties of Bitumen.* The purpose of this test was to determine whether any real benefit * Test made in Chemical Laboratory of the Public Service Commission for the First District, State of New York, R. L T Oberholser, Chief Chemist. TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 239 6 22 O O O O O mill iiiiii l _-. o!!oo~o~o~o"o"o"o~o H gi SS T3 *d TJ TJ fl ' "^ ' "~ 0^ C j? I ^ 3 e ^| 1|I t|llllllllll.s r*1 F^H K"^ >*"^ K*^ K"^ t*"' ^^ L/^ l-/^ >-/J L/^ *^ ^ I 7 " "1 &*'$> w '> o 6666^ ^ fi 8 fi cccotntoa* ^'o.^ c; ''Q. oo3(:3ci3c3 a t>- K f 'a'a a a'a'a a JL 111111111 5 '5 $$'.$. 'S - li ^ a Sb Sb Sb Sb 5b 17 ~V" ,_ - ^- ^_, i LT^ f^ LT^ W^> lf^ 1<"^ >f lf^ >^ >*^ 1^ *O CO -^3 240 WATERPROOFING ENGINEERING accrues to waterproofing asphalt by the incorporation of asbestos of the shredded or fibrous variety, as was the practice on some of the subway work in New York City. In preparing the specimens the bitumen was heated until liquefied and the various amounts of asbestos added and stirred until the mixture was a homogeneous mass. Table XV shows the results of the test. TABLE XV. EFFECT OF INCORPORATING ASBESTOS FIBER IN BITUMEN Specimen Number. CONTENTS, PER CENT. Ductility at 32 Degrees Fahren- heit. Ductility at 62 Degrees Fahren- heit. Ductility at 77 Degrees Fahren- heit. Melting- point Kraemer and Sarnow Method, Degrees Fahrenheit. Pitch. Asphalt. Asbestos. 1 2 3 100 99 99 98 98 97 i i H 2 3 i 1 H 2 3 U l 3 H 2 3 4 1 2 2 13 11 10 8 8 7 7 8 8 9 35 17 16 7 13 7 20 10 11 13 11 10 100 110 113 119 140 119 126 130 128 165 154 143 4 5 6 7 8 9 100 99 99 98 98 97 10 11 12 The most evident conclusions from this test are, that due to the presence of the asbestos the ductility of the bitumen is considerably decreased and the melting-point is increased. The former fact indicates that the mixed bitumen would not hold together in the form of a thin coating as well as the pure bitumen, while the latter indicates that the mixed bitumen would flow with greater diffculty than the pure bitumen at the same temperature. Ductility of Asphalt Containing Coal-tar Pitch. The purpose of this test is to determine the effect on the ductility of asphalt of the addition of coal-tar pitch in various percentages. Both the asphalt and the pitch were of the grade regularly used in waterproofing the dual subways in New York. The melting-point of the pitch was about 116 deg. Fahr. (47 deg. Cent.) by the cube-in-water method, and the asphalt about 120 deg. Fahr. (49 deg. Cent.) by the Kraemer and Sarnow method. TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 241 Starting with the pure asphalt in a molten condition the mix- tures were made by adding the pitch in increments of 5 per cent by weight. The specimens were then tested and gave the following results: The melting-points of the mixtures showed a decided but not constant increase with increase of pitch. The penetration of the mixtures showed an almost constant decrease and at propor- tions between 25 and 40 per cent of asphalt the penetration approached zero. The addition of 30 to 40 per cent of pitch to the asphalt reduced the ductility of the mixture to zero, while even as little as 5 per cent reduced the asphalt's ductility from more than 100 to 30 or 40 cm. It seems, therefore, inadvisable to mix coal- tar pitch and asphalt when this is intended for waterproofing by the membrane system. It may, though, be good as a waterproof or dampproof surface coating on masonry suited for its application, or as a roof flashing compound. A waterproofing membrane must be elastic and ductile to a reasonable degree to avoid cracking in conjunction with the structure it surrounds. Mixing these two materials tends to vitiate this by giving the product the property of " shortness," or lack of ductility. It should be remembered, however, that inferior grades of pitch might even have a deleterious effect on the asphalt or vice versa. Effect of Temperature on Penetration and Ductility of Asphalt and Coal-tar Pitch. The penetration and ductilities noted in these tests were made with the Dow penetrometer and tensometer, both standard testing machines used in asphalt laboratories. Fig. 108, which is quite self-explanatory, shows that according to penetration the coal-tar pitch, though of lower melting-point, and tested in both pure and mastic forms, is harder at low tem- peratures and softer at high temperatures than the asphalt; also that the asphalt has a wider temperature range, that is, the asphalt is less affected for a given temperature change and softens more slowly than coal-tar pitch. The curves in Figs. 109 and 110 show the relative penetration and ductility of asphalt and coal-tar pitch whose melting-points are practically equal, as determined by the Kraemer and Sarnow method. From a study of the penetration curves the following facts may be noted: (1) The asphalt and its mastics are softer than coal-tar pitch between the approximate limits of 40 and 90 deg. Fahr. (4.5 and 32 deg. Cent.). 242 WATERPROOFING ENGINEERING . |1 $ r II OJ O C ri 1 s 1 1 ^ .g ) 9 8 ^ .S o i 1 ft i h J N ^g d *C n. ^3 o* 1 | J 1 55 ' <3 OQ *1 CO ^ '^uauiaQ puB os puBg+ ^Bqdsy 00 00 ^O 00 O Tjl - 00 *O iO 00 O TjJ Ni - O O Q] *j|o w puBg+ qa^tj paBH CO "O CO O 00 O ro S 33* b- O CO o o o - S 5" N puB puBg+ q'o^ij I-H CO O ^H (N 00 OWTO IO O5 00 o o o t. puB pUBg+ qo;i j i-i b^ 00 O rH O -o CO ;5 " ;rt Illlll Q^Q Q^ PH 02 EH 311 I? I'l Be Iff '* - S II i P,S s lilll PL,KO<5<5 244 WATERPROOFING ENGINEERING (2) The coal-tar pitch curves show that the pitch is more affected by change of temperature than the asphalt. This is not quite obvious, however, unless we assume a common point for both curves, which would very likely be near the melting-point of both materials. Then, if measured from this point, the above fact is readily proved. (3) Of both pitch and asphalt mastics the pitch mastic of pro- portions 2 : 2 : 1 is more affected by temperature changes. (4) Of the asphalt mastics, the one of proportions 1:1:1 is least affected by temperature changes. Melting Points (K.& S.Method) Asphalt 126 F. Coal-tar Pitch 103 F. 30 110 60 70 Temperature, Deg. Fahr. FIG. 108. Relation of Penetration to Temperature of Asphalt and Coal-tar Pitch; also Asphalt and Coal-tar Pitch Mastic, Mixed in the Proportions of 1 Part Bitumen, 1 Part Sand, and 1 Part Limestone Dust. (Points of Curves are the Means of three Sets of Readings on Penetration Machine Using a No. 2 Cambric Needle, Weighted to 100 Grams and Acting for Five Seconds.) The following conclusions are noted from a study of the ductility curves : (a) Asphalt and its mastics are more ductile than coal-tar pitch (both of the same melting-point), but its rate of change of ductility is less, hence it is less affected by temperature changes. (6) For work exposed to great temperature changes the asphalt is to be preferred to coal-tar pitch. For work not exposed to great temperature changes coal-tar pitch is to be preferred on account of its greater chemical stability. TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 245 246 WATERPROOFING ENGINEERING TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 247 Comparative Tests on Coal-tar and Asphalt Mastics.* Here- tofore asphalt alone Has been used for making mastic for brick-in- mastic usually used for waterproofing underground structures. The purpose of these tests was to ascertain the adaptability of straight- run coal-tar pitch for making mastic for the same purpose. The tests were made to cover the requisite properties of a mastic for waterproofing by this method, these properties being as follows: (1) The mastic must have a small and limited compressibility at a temperature between 32 deg. Fahr. (0 deg. Cent.) and 77 deg. Fahr. (25 deg. Cent.) (2) It must be flexible or pliable, that is, it must be able to bend on itself without fracture at 40 deg. Fahr. (4.5 deg. Cent.) or less. (3) It must be adhesive and cohesive enough to heal at 40 deg. Fahr. or less. (4) It must be tough enough at 32 deg. Fahr. to resist cracking due to impact and vibration caused by moving loads. (5) It must be reasonably ductile at temperatures between 32 deg. Fahr. and 77 deg. Fahr. (6) It must be of uniform consistency however proportioned. (7) The extracted bitumen must have very little (not more than 3 per cent) volatile oil. (8) The mineral aggregate must pass 100 per cent through a 10-mesh sieve. Two kinds of coal-tar pitch and one of asphalt were used in making the test specimens. One pitch was a straight-run product meeting the specifications given on page 281; the other was also a straight-run product brought down to the same penetration as the asphalt under test. The asphalt was a refined Mexican oil made to meet the specifications given on page 282. Two sets of tests were made. In one, the ingredients were pro- portioned by weight one sand, one limestone dust or cement, four bitumen. In the other, the ingredients were proportioned by volume one sand, one limestone dust or cement, two bitumen. The reason for making two sets of tests, one with about twice as much bitumen as the other, was to ascertain the relative effect on the properties of the mastic by the presence of more or less bitumen. Since in the past asphalt mastic has been used exclusively in the brick-in-mastic system of waterproofing, and since there is no reported failure of this method or material, it was accepted as the Test made under supervision of author in the Research Laboratory of the Barrett Company, in 1915. 248 WATERPROOFING ENGINEERING standard, i.e., all results were compared to the results obtained on the asphalt mastic. These values, given in Table XVI, were averaged and the following conclusions are drawn from a study of this table: (1) A limited amount of compressibility being both useful and necessary in a bituminous mastic, this property shows up generally in favor of the hard-pitch mastic. (2) Penetration a measure of the hardness of the mastic, but not a very reliable test, owing to the presence of sand particles is generally in favor of the hard-pitch mastic. (3) The bending test, showing the temperature at which fracture will occur, shows in favor of the soft-pitch mastic ; this may be bent at about 140 deg. Fahr. (60 deg. Cent.) lower than the hard-pitch mastic. (4) The healing test, probably the most important, indicating the inherent capacity of the mastic to restore itself after cracking, shows in favor of both pitch mastics. (5) The impact test, indicating the resiliency of the mastics, a property important for the conditions under which the material is usually used, shows in favor of the soft-pitch mastic. (6) The ductility test, indicating the tenacity of the material, shows in favor of the soft-pitch mastic. (7) The gas-drip test, indicating the capacity of the material to resist the deteriorating effect of gas-polluted earth, shows in favor of both the pitch mastics. This resistance is mainly due to the presence of the free carbon in the pitches, but is obviously not a governing property. From the foregoing it is evident that both pitches are better in some of the desirable properties than the asphalt, but neither excels in all the requisite properties. But by interpolating the results given in the table, a grade of coal-tar pitch was evolved, meeting the specifications for brick-in-mastic waterproofing given in Chapter VIII, and this may be used under the same conditions where the asphalt mastic is used. Volume Reduction of Asphalt Mastics. In the mastic and water- proofing industries it is a matter of common knowledge that the volume of the finished mastic is not equal to the total volume of its ingredients, just as in the case of concrete. The loss in volume was assumed to be anywhere between 5 and 20 per cent. The follow- ing test was therefore made to determine this value with closer approximation : Equal volumes of asphalt, sand and cement were mixed in a TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 249 fire-heated kettle until a satisfactory mastic was formed. The volume was then measured and found to be approximately 30 per cent less than the total volume of ingredients. Another mastic was then made with equal volumes of asphalt and mineral aggregate; the latter composed of one part cement and three parts sand. This mixture showed about 20 per cent loss in volume. Other mixtures were made and showed losses between these limits depending on the proportions of sand and cement in the mineral aggregate, and the length of time the mastic was stirred. This established the fact that 20 per cent and not 5 per cent is the mini- mum, and about 30 per cent the maximum reduction of volume for mastic used with bricks to form what is known as the brick-in- mastic waterproofing envelope. But even these figures are materi- ally affected by the duration of the mixing process, the volume further decreasing with prolonged stirring. Mastic Bond Affected by Surface Condition of Bricks. In an effort to determine the relative bonding power of waterproofing mastic on bricks in various conditions, the following test was made: Five bricks were embedded in a 50 per cent asphalt mastic, that is, a mastic composed of fifty parts asphalt and fifty parts mineral matter. The first brick embedded was dry and clean; this was followed by a moist brick, then by a wet brick, then by two bricks somewhat blackened with soot, as would be the case if the bricks were dry heated over an open wood fire, as is often done. When the mastic cooled and hardened the bricks were pulled up and showed the following: (1) The dry and clean brick could not be extracted from the mastic intact. (2) The moist brick showed but little bond and was easily extracted. (3) The wet brick showed no bond at all. (4) The soot-blackened bricks showed fairly good bond, enough to demonstrate that a thin coat of soot is not objectionable in brick- and-mastic work. Relative Compression of Plain Brick, Brick and Mortar and Brick- in-mastic. The brick-in-mastic specimens were made in accord- ance with prevailing practice, that is, two bricks were laid in mastic, side by side, on their largest bed, as stretchers. But for testing, the specimens were not incased in concrete, as is usually done in prac- tice. The specimens were four bricks high, with a minimum of |-inch joints and each completely covered with asphalt mastic. The proportions of the mastic ingredients were about 40 per cent asphalt, 250 WATERPROOFING ENGINEERING 30 per cent sand and 30 per cent cement, by weight. The bricks were the ordinary building variety, 2J by 3f by 8 inches. The joints of the wooden form used for making the specimens were purposely made not absolutely tight, as this is a condition which occasionally occurs in practice. As a result, some of the hot mastic leaked out, leaving a considerable void between two bricks above the level of the leak. One of the forms was also made somewhat narrow, that is, its width did not permit more than about a -j^-inch joint. The result was that on inserting the brick the mastic was squeezed out between the form-side and brick. The latter was in consequence only partly covered with mastic. These conditions illustrate the necessity of making tight-joint forms and also wide enough to allow sufficient mastic between all brick faces. Three specimens were made as above noted (in good forms) and when tested for compression at about 70 deg. Fahr. (21 deg. Cent.), gave the results noted in Table XVII, to which, also, are added for comparison, the ultimate compressive strength of plain brick and brick and mortar. TABLE XVII. ULTIMATE COMPRESSIVE STRENGTH OF BRICK AND MASTIC, BRICK AND MORTAR AND PLAIN BRICK ULTIMATE COMPRESIVE STRENGTH (Lb. per Square Inch) Brick and Mastic. Brick and Mortar.* Plain Bricks.f 360 2520(a) 5120 281 2440 (a) 5060 421 3776(6) 4880 *Compression on column./S X8 inch base, 1 foot 4 inches high, of common brick and mortar, (a) Lime mortar, 1 : 3 proportion; (6) Portland cement mortar, 1 : 2 proportion, t Compression on largest bed of single bricks. On all three tests of the brick-in-mastic, the bricks failed first. The reason for this is that the mastic, when compressed, tends to spread and actually does so, and however slight this may be, it places the brick under a transverse tension, consequently reducing its compressive strength, as indicated in the table above. However, it should be borne in mind that the compressive strength of brick- in-mastic would be increased considerably, perhaps quadrupled, by being encased in concrete, as it actually is in practice. The temperature of the brick-in-mastic will also have a marked effect TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 251 upon its strength. A continued, comparatively low temperature, however, will not prevent the ultimate destruction of the bricks by transverse tension, but only retard it, unless, of course, the brick- in-mastic is well encased in masonry to prevent it. Effect of Temperature of Saturants on Waterproofing Fabrics. The purpose of this test was to determine (1) the effect of high tem- peratures on waterproofing felt and fabrics while in course of treat- ment; (2) the charring temperature of these materials; (3) the result of treating fabrics without the use of the usual compression rollers. Specimens of cotton drill and open-mesh jute burlap were cut into workable pieces and treated as follows: Eighteen pieces were saturated with asphalt at different temperatures ranging from 180 deg. Fahr. (82 deg. Cent.) to 500 deg. Fahr. (260 deg. Cent.), raised by increments of 30 deg. Fahr. ; fourteen pieces were saturated with coal-tar pitch at different temperatures ranging from 180 deg. Fahr. to 420 deg. Fahr. (215.5 deg. Cent.) raised by increments of 25 deg. Fahr. ; ten pieces were saturated with a mixture of asphalt and coal- tar pitch in equal proportions; the temperatures of the mixture ranged from 300 deg. Fahr. (149 deg. Cent.) to 520 deg. Fahr. (271 deg. Cent.), raised by increments of 50 deg. Fahr. The melting point of the pitch used was about 120 deg. Fahr. (49 deg. Cent.) and that of the asphalt about 160 deg, Fahr. (71 deg. Cent.), both determined by the cube-in-water method. The method of saturating the forty -two specimens was as follows: Each piece was drawn slowly, as in practice, through its saturant, completely immersed, and, when withdrawn, was hung up imme- diately to dry in the air. Of course, this is not the method used by manufacturers of waterproofing products for treating fabrics. At the factory the felts and fabrics are drawn through steam-heated compression rollers immediately after they leave t:^e saturating tank, which operation forces the compound into the fibers and removes the excess saturating material. (See Fig. 60.) It was interesting and instructive to know though what the re- sulting condition of the product is when treated as above. All were well saturated but excessively coated with bitumen. The burlap specimens showed very few or no open meshes remaining. Both the asphalt- and pitch-saturated specimens, when weighed, showed a gradual decrease in the amount of saturant with the increase of tem- perature, but the " A.-P." (asphalt-pitch) mixture saturated specimens showed almost constant weight of saturant notwithstand- ing increase of temperature; in other words, the " A.-P." mixture 252 WATERPROOFING ENGINEERING remained at practically the same consistency while the others became more fluid. The pitch-saturated fabrics lost their tackiness first, then the "A.-P." saturated fabrics and lastly the asphalt-saturated fabrics. The " A.-P/' mixture saturated specimens were devoid of ductility, cracked easily on being bent around the finger at normal tempera- ture and showed a dull-black, rough and pitted surface. The asphalt-saturated and pitch-saturated samples showed a smooth and lustrous surface. Several specimens of untreated felt, raw burlap and cotton drill were then put into a sand bath and heated gradually; at about 400 deg. Fahr. (204.4 deg. Cent.) the felt charred; at 425 deg. Fahr. (218.3 deg. Cent.) the burlap charred and at about 450 deg. Fahr. (232.1 deg. Cent.) the cotton drill began to char. The charring temperatures thus obtained verified previous values obtained dur- ing the saturation process. Manifestly the fabrics must be drawn through compression rollers to obtain not only good saturation but also the proper amount of coating and, in the case of burlap, sufficient open mesh in the finished product. The temperature of the saturant has much to do with the degree of saturation and is, in fact, almost proportional to it. The possibility of charring the felts and fabrics during treatment is remote because such temperatures never exceed 350 deg. Fahr. in practice and besides, the bitumen, especially the pitch, would be injured first by over-heating, and detected by the excessive fumes it gives off at the higher (charring) temperatures. The saturant composed of equal parts of asphalt and coal-tar pitch is obviously not as good as either of the other two when used as a saturant for fabrics. RELATIVE AMOUNT OF SATURANT AND COATING MATERIAL ON TREATED WATERPROOFING FELTS AND FABRICS It has often been stated that jute fabric cannot be saturated as well as felt. The results noted in Table XVIII indicate that this is true for asphalt-treated fabric but quite the reverse for pitch- treated fabric. It must, however, be borne in mind that the satura- tion of the jute fabric, even with asphalt, is only a preliminary step to its final treatment, while with the saturation of the felt its treat- ment is completed. This is true of most asphalt- and all pitch- treated felts. On the other hand, saturated cotton fabric (satura- tion being its only treatment) has 25 per cent more saturant than the felt. TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 253 TABLE XVIII. RELATIVE AMOUNT OF SATURANT AND COATING ON TREATED WATERPROOFING FELTS AND FABRICS No. Material. WEIGHT IN GRAMS PER SQUARE FOOT. TREATED MATERIAL (BASED ON RAW MATE- RIALS). Un- treated. ASPHALT- TREATED. PITCH- TREATED. Satu- rated. Satu- rated and Coated. Satu- rated Satu- rated and Coated. Per Cent of Satu- rant. Per Cent of Coating Per Cent of Total Bitu- men. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Averages .... 21.70 25.56 20 30 22.59 21.60 24.55 21.60 21.20 19.95 21.15 22.00 20.18 21.70 19.10 20.35 19.55 18.45 21.05 22.50 20.30 20.30 28.75 25.25 22.25 28.89 27.40 20.55 25.50 29.90 17.30 26.20 25.60 21.60 24.10 59.35 58.51 50.60 64.20 73.80 91.70 66 . 40 17.05 19.30 18.20 29.80 59.80 35.82 45.80 71.30 80.11 61.82 68.00 50 35 37.1 133.0 76.4 102.0 190.0 79.4 128.0 98.0 227 213 204 202 133 150 177 124 251 256 306 203.9 157 295 328 251 287 286 266 286 269.5 33.65 37.60 36.55 39.70 61 . 45 59.95 47.50 70.05 75.35 89.40 61.20 ...".. 37.0 113.0 88.0 72.7 162.0 183.0 47.05 59.90 52.10 51.90 62.30 58.90 64.20 49.65 55.70 62.85 65.00 47.50 66.17 52.90 35.62 55.30 56.00 75.75 87.25 68.75 71.60 81.45 82.70 78.70 75.30 78.0 116.0 214.0 155.0 165.0 237.0 179.0 185.0 143.0 174.0 118.0 156.0 113.0 135.0 03.0 73.2 114.7 165.0 101.0 116.0 107.0 106.0 119.0 104 136.2 41.2 82.9 172.0 86.1 50.2 107.0 81.8 142.0 95.4 Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Open-mesh jute fabric Averages Felt (light grade) . . Felt (light grade) . . Felt (light grade) . . Felt (light grade) . . Felt (light grade) . . Felt (light grade) . . Averages 79.25 34.70 56.80 53.05 44.70 53.70 121.20 182.14 125.50 157.60 161.90 157.10 150.90 Felt (light grade) . . Felt (light grade) . . Felt (light grade) . . Felt (light grade) . . Felt (light grade) . . Averages Felt (heavy grade).. . Felt (heavy grade).. . Felt (heavy grade).. . Felt (heavy grade) . . . Felt (heavy grade) . . . Felt (heavy grade) . . . Averages Cotton fabric Cotton fabric Averages 211 146 145 119 71 132 7 43.05 45 52 152.0 135 44.30 143.5 254 WATERPROOFING ENGINEERING It has also been stated that an asphaltic-treating compound for jute fabric intended for membrane waterproofing with coal-tar pitch as a binder is injurious to the membrane because the two materials are forced to mix (on account of the binder being applied hot), and produce thereby an inelastic and perhaps deleterious compound. Careful investigation, however, seems to show that the amount of treating compound used in the fabric is so little in comparison with the amount of binder used in the membrane that there is no apparent harm in using asphalt-treated fabric with coal- tar pitch binder. The results of weights of specimens noted in Table XVIII permit the determination of the proportion of treating com- pound to binder used to form, say, a 3-ply or a 6-ply membrane; for instance, a square foot of a 3-ply fabric membrane, approximately J-inch thick, weighs 2 pounds, of which 80 per cent is pitch-binder and 15 per cent asphaltic-treating compound. Pitch and asphalt in these proportions, were they actually mixed, would not produce a very bad compound to be used as a binder. In the field, not more than the coating on the fabric mixes with the binder, therefore the percentage of treating compound that mixes with the binder is still less than that given here. Further facts disclosed in Table XVIII are that though asphalt- treated jute fabric has only about 75 per cent as much total bitumen (that is, saturant plus coating material) as the pitch-treated fabric, the amount of coating proper on the asphalt-treated fabric is 45 per cent greater than that on the pitch-treated fabric. Asphalt-treated and pitch-treated felts of approximately the same weights are equally well saturated, but heavy felts contain about 10 per cent more saturant than lighter felts. Effect of Drinking Water on Waterproofing Fabrics. The pur- pose of this test is to determine the effect on treated and untreated fabric of one-half year's immersion in water and one-half year's gradual drying. In March, 1914, nine specimens of jute fabric, some treated with asphalt and some with coal-tar pitch and one untreated specimen, were immersed in plain water, contained in a rectangular tank 1 by 1 by 3 feet. The specimens were suspended from strings stretched across the tank and labeled for identification. The water was constantly replenished for six months after which it was allowed to evaporate completely, which also took about six months. In March, 1915, the specimens were carefully examined, and the following results noted. The untreated jute burlap though thor- TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 255 oughly wet for at least six months, had retained its strength com- pletely but was a little stiff and darker in color than originally. The bituminous treated specimens showed hardly any loss of strength and practically no deterioration. Where the coating on the fabric was good originally, the fabric was entirely unaffected, that is, no water penetrated the fabric fibers. The bitumen retained its elasticity and the fine sawdust, which is sprinkled on the surface of the fabric to prevent self adhesion in the rolls during shipment and storage, remained intact. Where the fabric was poorly saturated, a slight loss of tensile strength was mani- fested. In general, however, the asphalt treated specimens showed somewhat less resistance than the specimens of fabric treated with coal-tar pitch. The test proves (1) the value of thoroughly coating and saturating the fabric, because thereby it is prevented from absorbing water, and (2) that plain water is not particularly injurious to bituminous treated fabric. Effect of Ground Water on Waterproofing Fabrics. To deter- mine the effect on fabrics treated with asphalt and with coal-tar pitch by the action of ground water in direct contact with them, thirteen specimens of treated jute fabric, each about 4 by 6 inches, were buried about 3 feet in the ground at City Hall Park, N. Y., near the new Broadway Subway location, for a period of 106 days (from May 6th to August 22d, 1914). Table XIX shows the char- acteristics of the interred waterproofing fabric. In another test similar to the above, various grades of cotton fabric, paper fabric and felt were buried in the ground at Battery Park, N. Y., at a depth of 4 feet. In less than three months, when the specimens were examined, it was found that the cotton and paper fabrics had almost completely decayed and the felt had become so brittle that it broke in handling. Another test of a similar nature with various cotton, jute and felt specimens, but this time each heavily coated with pitch or asphalt, showed on examination, after 2 months' burial, that both the fabric and felt were well preserved though the coatings were considerably pitted. In each of the above tests the specimens were obtained from various manufacturers. These tests conclusively prove the necessity of thoroughly coat- ing any felt or fabric used as reinforcement in a bituminous water- proofing membrane. Also that the binder and not the felt or fabric is the waterproofing material in such a membrane- 256 WATERPROOFING ENGINEERING TABLE XIX. EFFECT OF GROUND WATER ON WATERPROOFING FABRICS BEFORE BURYING. (1). 7 oz. open-mesh asphalt- treated fabric; well saturated and coated. 2. 7 oz. open-mesh asphalt- treated fabric; well saturated, one side well coated, other side poorly coated. (3). 7 oz. open-mesh asphalt- treated fabric; well saturated and coated. (4). 7 oz. open-mesh asphalt-treated fabric; poorly coated; not saturated. (5) 8 oz. open-mesh oil-tar pitch- treated fabric; poorly saturated but well coated; pliable. (6). 8 oz. open-mesh oil-tar pitch- treated fabric; well saturated and coated; somewhat stiff and brittle coating. (70- Seven pieces of 7 oz. open -mesh asphalt- and pitch-treated fabric, more or less well saturated and coated. AFTER BURYING. Shows almost complete decay. Both asphalt and burlap are very brittle. No " life " left. Shows no strength. Asphalt coating very brittle. Burlap saturated with water. Shows brittleness and more or less decay. Lacks strength. Shows almost complete decay. Very brittle. Shows almost complete decay. Re- mainder is pliable but weak. Is brittle, weak and decayed in several spots. Specimens so badly deteriorated that identification is impossible. Relative Absorption and Strength of Raw and Treated Water- proofing Felts and Fabrics. To determine the relative amount of water absorbed by various waterproofing felts and fabrics, and also their relative tensile strength and stretch, 88 specimens, of which 35 were untreated, and the remainder treated with either asphalt or pitch, were partly immersed in water for three hours and weighed before immersion and at the end of the first and third hours. Then the specimens were allowed to dry, after which they were cut into 1-inch strips and tested for strength and stretch on a stretching machine. A review of Table XX reveals the following facts : 1. Untreated jute burlap is much more absorbent than paper fabric, cotton fabric, felt, building paper, and ready-roofing, all untreated, TECHNICAL AND PRACTICAL TESTS ON WATERPROOFING 257 2 ill TO COW COCO COCOCO CO CD COCOOJ G CG CG CGG G G GCG d> cuo c;cu cpi;cu d> cu CL>CPCI> 111 .s s.a .a.a .aj.a _s .a .a.a.a III CO CO CO *o *o*o *o*o *o*o"5 *o "o o o cj 0^0> 000 S^^ & && aa && n a & &&& s t^CN CO CO OiCO CO CN COCOCO CO CM ^ CN CM "o ^ "o'o'o G S *o "0*0 g "0*0 'o'o'o *o *o g "0*0*0 01 01 W S 2 til tifi bC.S tyDtslD btbOM bO b .5tdDbCbfl 222 OJ Oi Oi El z. ^ i ! 11 Sas illi < ^^^ ^^ 55^ < < ^-<^-< 1! HC. 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II; l.i F>? >. a a 1 11 "j : ': i-g : -g 2 : : 2 2 "B -2 2 " 2 oil CC 3 3 ' "S ' * ^ ' ^ ' "S 3 ti -i S3 ^2 E 42 "S T3 B M PH 1 II S 'C 42 s Is |S| If is 1 S 1 u 'o 4 - Itl ti * a .S 'a M a g ^H ^H e CO i ? g 2 ; g 43 ^ 43 ^ -^ -^ a S n OQ GO I O I 1 I o ^ O ^ -S ^ 3 4 * !l f^ H , O 'S r .3 i ^ H membrane, o . . o> o &'^ oT 42 1 1 42 1 concrete i square rod tl, 1 ft.-6 8 side all steel r eet above M as outside ; ~ o> QJ G o O B 43 2 13 $ j>> "a 11 1 8 1! |l i X 1 II- 9 S ~ 5 b^ S s 1 111 3|8 1 S ^ja 3 Layers of Burlap (0_) SECTION OF FIXED JOINT AT OFFSET IN WATEBPROOFING SURFACE irface of Waterproofing to conform to Surf ace or Base Coat of Primer Asphalt CD) TRANSVERSE SECTION OF WATERPROOFING Expanded Metal (E) TRANSVERSE SECTION OF SLAB (F) LONGITUDINAL SECTION OF WATERPROOFING 3 Layers of Burlap-. (GJ DETAIL OF SUMMIT 2 Layers ofjlar Paper ) _ A (H) SECTION OF EXPANSION JOINT FIG. 112. Standard Methods of Waterproofing Bridge Floors, C. M. & St. P. Ry. Protect the concrete from the sun for twenty-four hours after laying. The joints in the expanded metal should be lapped 6 inches. (See (d) Fig. 112). After the work has been brought up to the desired point from both sides, interlap, in order, the strips which reach across the joint, mopping asphalt between burlap surfaces. Place a strip of burlap WATERPROOFING SPECIFICATIONS 295 along the joint for a closing strip; complete by laying the upper | inch of asphalt as before described. See (g) Fig. 112. If possible the waterproofing should be laid in one run the full width transverse to the drain slope of the surface to be waterproofed. The ends of the burlap strip should be flashed into recesses in the walls, curbs or parapets as shown &t (e). Where longitudinal joints are necessary cut the burlap long enough to extend 12 inches beyond the primed and asphalted surface of the concrete and use care as the strips are laid that the 12-inch strip is kept free from asphalt. When the succeeding section is to be waterproofed, fold back the projecting strips of burlap over the completed waterproofing and bring the new up against the completed portion of the water- proofing, interlapping the projecting ends of the burlap with the new burlap as the work progresses; this is shown at (/). On concrete trestle or subway slabs longitudinal joints in the waterproofing should preferably be on the center line of the slabs. If it is neces- sary to place joints in the waterproofing over joints in the slabs special care should be taken. Lay two continuous strips of tar paper 36 inches wide over the expansion joint, being careful to see that no asphalt gets between or under the two strips of tar paper. Then mop the top strip with hot asphalt and carry the waterproofing over the top of the paper the same as if no joint existed. See (6) and (h). The burlap is to be a treated, 8-ounce, open-mesh burlap fur- nished in widths of 36 to 42 inches. The concrete is to be one part Portland cement, two parts tor- pedo sand and three parts stone or gravel that will pass a J-inch ring. The mortar is to be one part Portland cement and two parts washed torpedo sand. The primer is made by pouring hot asphalt in 80 deg. Baume" gasoline until mixture will spread readily with a brush. Pure asphalt conforming to accepted specifications is to be used. Before using the asphalt heat it in a suitable kettle to a temperature not exceeding 450 deg. Fahr. (232 deg. Cent.). The temperature is to be taken with a thermometer. Asphalt heated above 450 deg. Fahr. or giving off yellow fumes is to be discarded as overheated. The expended metal is to be equivalent to (manufacturer's name stated) " 2J-inch No. 16 Regular " expanded metal. The tar paper will be furnished in rolls 36 inches wide. Remarks. In describing the color of fumes coming from the sur- face of overheated asphalt as being yellow, the author desires to 296 WATERPROOFING ENGINEERING correct this general misconception and state that the fumes of burned asphalt are bluish black and the fumes of coal-tar pitch are yellow with a greenish tinge. Specifications for Waterproofing Concrete Structures on the Chicago, Burlington & Quincy Railroad. The waterproofing shall consist of a mat of four ply of burlap and one ply of felt thoroughly saturated and bonded together with waterproofing asphalt and covered with 1 inch of sand-and-asphalt mastic. No waterproofing shall be done when the temperature is less than 60 deg. Fahr. (15.5 deg. Cent.). The surface of the concrete shall be smooth, clean and dry. Upon this surface there shall first be applied, with brushes, a coat of priming paint, which shall be thin enough to penetrate the con- crete and form an anchorage for the waterproofing. After this priming coat has dried, a heavy coat of waterproofing asphalt, heated to a temperature of 400 deg. Fahr. (204 deg. Cent.), shall be applied with mops, the width of the burlap, and while this is still hot a layer of burlap shall be bedded in it. The burlap shall be laid just behind the mopping and swept with a broom, and must be free from folds and pockets. The surface of this burlap shall be heavily mopped with waterproofing asphalt, and three more ply laid in the same manner, making a four-ply burlap mat all thoroughly saturated and bonded together. The top of the burlap mat shall be heavily mopped and one thickness of felt saturated with asphalt laid on it, the edges lapped at least 3 inches, and sealed with asphalt. The top of this felt shall also be mopped with water- proofing asphalt. This shall then be covered with 1 inch of asphalt mastic laid in one layer, the mastic to be composed of one part of waterproofing asphalt and four parts of fine gravel graded from J inch to fine sand, the top leveled off with wooden floats and mopped with a heavy coat of asphalt. At all the expansion joints in the concrete a fold, to allow for the expansion of the structure, shall be formed by laying the burlap and felt over a 1-inch pipe and removing the pipe as the mat is being completed. Where the work is stopped before being completed, at least 3 feet of burlap at the end and half the width of the burlap at the side shall be left exposed to form a splice. Special care shall be taken to seal the waterproofing at the sides and ends of the bridge. The burlap and mastic shall be carried up the parapet walls at the sides and the ends concreted in a recess in the walls so that no water can enter. The burlap shall be carried down over the back walls at the ends of WATERPROOFING SPECIFICATIONS 297 the bridge to cover all construction joints and shall run into a line of tile to facilitate the escape of the water. The burlap shall be 8-ounce, open-mesh, high-grade burlap satu- rated with an asphalt meeting the specifications for waterproofing asphalt. It shall come in rolls which shall be placed on end for ship- ment and storage, and shall not stick together in the roll. The felt shall be a good quality wool felt, saturated and coated with an asphalt meeting the specifications for waterproofing asphalt. It shall come in rolls, which shall be placed on end for shipment and stor- age, and shall not stick together in the roll. It shall not weigh less than 15 pounds per 100 square feet. The primer shall be an asphaltic compound of approved quality and capable of adhering firmly to the concrete. The waterproofing asphalt shall meet the following requirements: (1) The specific gravity of the asphalt desired shall be greater than 0.95 at 77 deg. Fahr. (25 deg. Cent.). (2) The flowing-point shall not be less than 130 deg. Fahr. (54.5 deg. Cent.) nor more than 140 deg. Fahr. (60 deg. Cent.). (3) The flash point shall not be lower than 450 deg. Fahr. (232 deg. Cent.). (4) The penetration at 80 deg. Fahr. (27 deg. Cent.) for a period of thirty seconds shall be at least 15 mm. and must not exceed 20 mm. This penetration to be measured with a Vicat needle weighing 300 grams, one end being 1 mm. in diameter for a distance of 6 cm. (5) When heated to a temperature of 325 deg. Fahr. (163 deg. Cent.) for seven hours the loss in weight shall not exceed 2 per cent and the penetration of the residue at 80 deg. Fahr. and for the period of thirty seconds using the same instrument as described above shall not be reduced more than 50 per cent. (6) The total soluble in carbon disulphide shall not be less than 99 per cent. (7) The total soluble in 88 deg. naphtha shall not be less than 70 per cent. (8) The total inorganic matter or ash shall not exceed 1 per cent. (9) Cold test, (a) A cube of asphalt 1 inch on edge shall be soft and malleable at a tem- perature of deg. Fahr. ( 18 deg. Cent.). (6) A film of the asphalt having a thickness not less than ^ inch shall be so pliable at deg. Fahr. that it can be bent in a radius of 2 inches. The total time consumed in the bending of this film shall not exceed three seconds. (10) The asphalt shall not be affected by any of the. following solu- tions, after being immersed in them for a period of three days: (a) A 25 per cent solution of sulphuric acid; (b) a 25 per cent solution of hydrochloric acid; (c) a 20 per cent solution of ammonia. Remarks. The above specification differs from the previous one mainly in that it specifies a 1-inch thickness of asphalt mastic as a 298 WATERPROOFING ENGINEERING protective coat over the membrane. This is good practice but it requires very careful selection of materials, and good workmanship in its preparation and application for the best results. In describing the testing of the waterproofing asphalt, no mention is made of the method of determining the flowing-point. Besides, from the tem- perature given, it is evident that the melting-point is meant, and not the flowing-point, because the flowing-point is only a comparative test.* Limiting the work of waterproofing to an atmospheric tempera- ture of 60 deg. Fahr. is at least 20 deg. too high and therefore too restrictive a clause. A surface-coating of sand on top of the mastic is an advisable requirement, as this tends to prevent abrasion of the surface by the ballast. Specifications for Waterproofing Solid-floor Railroad Bridges, f The depth of steel or concrete construction shall be such as to allow a sufficient distance from top of rail to top of steel or concrete floor for proper waterproofing and protection from the cutting action of the ballast. Under ordinary conditions, a depth of from 3.5 to 4.0 feet from top of rail to clearance line below is sufficient. Provision shall be made for grades of at least 1 per cent on the floor of the bridge to remove water promptly. Where this cannot be done in the steelwork, cement mortar, with a minimum thick- ness of 2J inches, shall be placed so as to drain the water to the inlets. Cast-iron inlets shall be set at proper places in the floor and provided with movable top grates. The down-spout from each inlet shall be provided with a trap and cleanout, which shall be accessible from below the bridge. The down-spout shall be of wrought iron, and connected to a sewer or arranged according to local conditions. On top of the prepared surface of the concrete shall be placed either of the following: 1. One or more thicknesses of felt or fabric, of quality and applied as specified hereafter, together with proper protection. 2. Asphalt mastic at least 1J inches in thickness, of quality and applied as specified hereafter. Felt, Burlap or Fabric. When waterproofing material of this kind is to be used, either of the following types shall be adopted: 1. From four to six layers of felt. 2. One middle layer of treated burlap, with four layers of felt. 3. One layer of felt, two layers of burlap, and two layers of felt. * See Chapter VII on Flow-point Test. f Proceedings, American Society of Civil Engineers, Vol. 40, No. 10, WATERPROOFING SPECIFICATIONS 299 4. One middle layer of treated burlap, and two layers of asbestos felt. 5. Either one or two layers of treated cotton-drill fabric. After the completion of the felt or fabric waterproofing, the entire surface shall be covered and protected by one of the following methods : 1. Straight, hard-burned brick laid flat, with joints filled either with waterproofing compound or cement grout. (Waterproofing compound should only be used as a filler on flat or nearly flat surfaces.) 2. A layer of concrete from 2 to 2| inches thick with wire rein- forcement. 3. A layer of about 1J inches of asphalt mastic used only on top of asbestos felt. On top of the protection coat, and outside the line of the ties, a line of half-round cast-iron pipe, 6 inches in diameter, and per- forated frequently, shall be placed to collect the water and convey it to the inlets. All openings in the steelwork shall be thoroughly closed, either by calking with burlap dipped in hot asphalt, or by the use of sheet metal sufficient to maintain the concrete base before applying the burlap and asphalt. Wherever called for by the plans, the decks of the bridges shall be protected with 1:3:5 concrete, with f-inch stone or gravel, mixed as specified hereafter, finished with a 1 : 2 mix of cement mortar, \ inch thick, troweled to a smooth surface on top. This con- crete shall be allowed to dry thoroughly so as to prevent the forma- tion of steam when the hot waterproofing materials are applied. All vertical or sloping surfaces of concrete or steel shall be cleaned of dust, dirt, loose particles, paint, and grease. The use of a hand- bellows is recommended for cleaning loose dust and dirt from the surfaces. For cleaning paint and grease from the steel and freshen- ing the surfaces of asphalt, where a junction of old and new is to be made, or where a pocket of pure asphalt is used against the girders and the felt or mastic, gasoline shall be used, either by swabbing the surface with it, or by pouring a small quantity over the surface to be cleaned and setting fire to it. The use of a blow-lamp is also recommended. These surfaces shall then be painted with two coats of approved asphalt, diluted with gasoline. The materials of the first coat shall be proportioned so as to give a brownish tint. The second coat shall have a larger quantity of asphalt. 300 WATERPROOFING ENGINEERING Both coats of paint shall be thoroughly applied and worked into the surfaces, so as to give a uniform coating of the asphalt. Paint shall not be applied to damp concrete or steel. The paint- ing shall be done immediately in advance of the application of the waterproofing materials and before dust has had time to collect. If the concrete is damp before the waterproofing is applied, the surface shall be first covered with a 2-inch layer of hot sand and allowed to stand for from one to two hours, after which the sand shall be swept back, uncovering sufficient surface to begin work, and the operation repeated over a new surface. All concrete shall be of such consistency that when dumped in place it shall not require much tamping, and shall be laid with a view to be an aid to the watertightness of the structure, and not merely a support for the waterproofing materials. All showing surfaces shall be troweled to a smooth, hard surface. In cases where concrete haunching against girders is called for by the plans, forms shall be used, and the concrete shall be of a wet consistency. On the prepared surface, apply the specified number of layers of approved saturated and coated felt (with a finished surface) weighing about 14 pounds per 100 square feet. The bids shall be based on the use of the type of felt specified in the above paragraph, but additional alternate bids will be con- sidered, based on felts or fabrics other than these, which may be approved by the chief engineer. In the event of such alternate bids being made, the bidders shall present with them sufficient data as to the methods of manufacture, quality of materials, and references to places where such felts or fabrics have been used, giving dates of application. All materials shall be delivered on the work in their original packages, and properly branded. The asphalt used shall consist of fluxed natural asphalt, or asphalt prepared by the careful distillation of asphaltic petroleum. It shall contain, in its refined state, not less than 98 per cent of bitumen soluble in cold carbon-disulphide. The remaining ingre- dients shall be such as not to exert an injurious effect on the work. When 20 grams are heated for five hours at a temperature of 325 deg. Fahr. (163 deg. Cent.) in a tin box 2J inches in diameter, it shall not lose more than 2 per cent by weight, nor shall the pene- tration at 77 deg. Fahr. (25 deg. Cent.) after such heating, be less than one-half of the original penetration. The consistency shall WATERPROOFING SPECIFICATIONS 301 be determined by the penetration, which must be between .75 and 1.00 cm. at 77 deg. Fahr. The penetration indicated herein refers to the depth of penetra- tion, in hundredths of a centimeter, of a No. 2 cambric needle, weighted to 100 grams, at 77 deg. Fahr., acting for five seconds. The melting-point shall be between 150 deg. and 190 deg. Fahr. (66 and 88 deg. Cent.). A briquette of the solid bitumen, having a cross-section of 1 sq. cm., shall show ductility at 40 deg. Fahr. (4 deg. Cent.) and at a temperature of 77 deg. Fahr. shall show a ductility of not less than 20 cm., the material being elongated at the rate of 5 cm. per min. (Dow molds.) All flashing and reinforcing around inlets and other places speci- fied shall be carefully executed. Waterproofing shall not be done in wet weather, or at a tempera- ture below 32 deg. Fahr., without special orders from the chief engineer. The felt shall be laid shingle fashion, the first two layers longitudinally and the last three transversely to the center line of the bridge, where five layers are called for, and as specified in detail in other cases, and shall be carried up the haunching and made secure against the girder in a satisfactory manner. The flashing against vertical or inclined surfaces shall be in accordance with the direc- tions of the chief engineer, if not indicated on the plans. The first layer of felt shall not be cemented to the floor of a steel bridge, except around the drain outlets. On an arch bridge, the first layer shall be cemented to the top of the arch. At no point shall there be less than the specified number of thicknesses. As the hot asphalt is spread, the felt shall be immediately rolled into it, rubbed and pressed over the surface so as to eliminate air bubbles and insure thorough sticking. One mopful of the asphalt shall not be spread over more than 1 square yard of surface at one mopping. Not less than 2.5 to 3 gallons of asphalt shall be used on 100 square feet of a single layer of felt. The top layer shall also be mopped and the work done so that the layers shall be one compact mass. The finish of the waterproofing against the girders or concrete shall be made with a pocket of pure elastic asphalt of the quality specified above, except that the melting-point shall be between 140 and 180 deg. Fahr. (69 and 82 deg. Cent.), the ductility at 40 deg. Fahr. shall be at least 3 cm. and the adhesive qualities shall be satisfactory to the chief engineer. The surfaces with which this material comes in contact shall be dry, absolutely free from dust or 302 WATERPROOFING ENGINEERING grease, and, previous to its application, shall be covered with a thin paint made by dissolving the asphalt in gasoline. Particular care shall be taken to make a tight joint around gus- sets, stiffeners, and the ends of girders. Care shall be taken to prevent injury in any way to the waterproof- ing by the passing of men or wheelbarrows over it, or by throwing any foreign materials on it. After the waterproofing course has been completed, the horizontal surfaces shall be protected by a course of straight, hard-burned and dense brick, laid flat in a bed of 1 to 3 cement mortar, with full joints. There shall be not less than \ inch of mortar between the felt and the bricks. The brick shall not increase in weight more than 10 per cent when immersed in water for seven hours. The haunching, and about 18 inches in width of the horizontal surface adjacent to the haunching, shall be protected by about 2J inches of 1 : 3 : 5 concrete, reinforced with No. 8 or No. 10 wire cloth, electrically welded. Every care shall be taken to insure satisfactory and thoroughly watertight joints between the main layer of waterproofing and the girders; and special attention shall be given to stiffeners, gussets, etc. The waterproofing shall also be carried down over the back walls to below the elevation of the bridge seat, or as directed. Rolls of felt shall be stored on end, and not laid on their sides. Waterproofing shall be done only by experienced and expert waterproofers. Application of Waterproofing. Wherever called for, the decks of bridges shall be waterproofed with natural rock asphalt mastic, as specified below. The concrete, prepared as specified heretofore, shall be water- proofed with asphalt mastic equal in quality, as to ingredients used and resistance to water, to the following specifications: Sicilian rock asphalt mastic 60 parts Clean, sharp, graded grit and sand to pass a sieve of 8 meshes per inch 30 parts Asphalt as specified above for membrane binder 10 parts These proportions shall be varied when required by special con- ditions on the work. The mixture shall be made at the site of the work, shall be heated to a temperature of from 250 to 300 deg. Fahr. (121 to 149 deg. Cent.) and shall be stirred until all the ingredients are thoroughly incor- porated. It shall then be spread and thoroughly worked, to free WATERPROOFING SPECIFICATIONS 303 it from voids, and shall be ironed to a smooth surface with smoothing irons, if so directed. All mastic shall be applied in two coats, making the required thickness. The two coats shall break joints, and the mastic shall be distributed evenly. Where the thickness of the concrete plus mastic is less than 2J inches, the full thickness shall be made up of asphalt mastic. Pockets of asphalt shall be placed against all metal, and mastic along girders, around stiffeners, gussets, etc., as specified above. Great care shall be taken around expansion joints, drain-pipes, and similar places, where a separation may take place. After the mastic is laid, it shall be mopped with pure melted asphalt, and the surface shall be spread with a layer of clean, coarse sand, to harden the top. The pockets of asphalt placed against the girders, stiffeners and gussets shall be protected by about 2| inches of 1 : 3 : 5 concrete, reinforced with No. 8 or No. 10 wire cloth, electrically welded. The furnishing and erection of the steelwork for the bridge to be waterproofed will be executed under a separate contract, and the riveting will be completed, the erection finished, and the steel floor cleaned up ready for the waterproofing, before the work on this contract is begun. In addition to the foregoing, the contractor shall make a final cleaning of the steelwork before the work of water- proofing is begun. Specifications for Waterproofing Station and Platform Floors of Railroad Viaducts by the Sheet-mastic Method. Where an asphalt floor is called for on mezzanines or station platforms, it shall be laid on 2-inch, tongue and grooved, yellow pine, the maximum width of the board being 6 inches. This board surface shall not be mopped with asphalt, but shall be covered with a layer of one-ply building paper or untreated felt. Where the asphalt floor is laid on concrete, the dry-ply shall be omitted, and a mopping of asphalt substituted. The surface mixture shall consist of the following proportions by weight: Eleven and one-half (11J) parts of asphalt, ten and one- half (10|) parts of sand, thirty (30) parts of grit, forty-four (44) parts of limestone dust, and four (4) parts of Portland cement. The sand shall be clean, sharp, and free from dirt, mica and vegetable matter. It shall contain both coarse and fine particles and shall be graded according to the percentages herein specified. Sand which does not fulfill the above requirements in its natural condition shall be screened, washed, or mixed with other sand to produce a result in accordance with said requirements. Of the ten- and one-half (10J) parts of sand, 100 per cent shall pass through a 304 WATERPROOFING ENGINEERING ten-mesh sieve; 40 per cent shall pass through a forty-mesh sieve, 10 per cent shall pass through an eighty-mesh sieve. All the grit shall pass through a four-mesh sieve, 30 per cent through an eight-mesh sieve, and 100 per cent shall be retained on a sixteen-mesh sieve. All limestone dust shall be of such fineness that it shall leave a residue of not more than 20 per cent on a hundred-mesh sieve, and not more than 90 per cent on a two hundred-mesh sieve. The fineness of the Portland cement shall be such that it shall leave, by weight, a residue of not more than 8 per cent on a hundred- mesh sieve, and not more than 25 per cent on a two hundred-mesh sieve; the wires of the sieves being respectively .0045 and .0024 inch in diameter. All proportions herein mentioned are by weight. The asphalt shall conform to the requirements (given in the specifications for " Waterproofing Subways by the Membrane System," page 281), except that when 20 grams of the material are heated for five hours at a temperature of 325 deg. Fahr. (163 deg. Cent.) in an electric oven, the loss in weight shall be not more than 1 per cent and the penetration shall be between .30 and .50 cm. at 77 deg. Fahr. (25 deg. Cent). The asphalt floor mixture shall be made in an approved mechani- cal mixer or by hand in open fire-heated kettles. When made by machine, the ingredients should be weighed out and put into the mixer which shall cook and mix the mastic until it is of uniform con- sistency and temperature. Pre-heating of ingredients is dependent on the type of machine used, and shall be resorted to as directed by the engineer. At the end of each day's work, the mixer shall be thoroughly cleaned. All materials used in making mastic should not be unduly exposed to the weather. The mastic shall be brought to the place of application in wooden pails properly covered so as to retain the heat. The temperature of the mastic in the mixer should not exceed 400 deg. Fahr. (204 deg. Cent.) and it should not be less than 300 deg. Fahr. (149 deg. Cent.) at the time of application. When the mastic is made by hand, the sand, grit, limestone dust, cement and asphalt shall be heated to approximately 325 deg. Fahr., the asphalt being heated separately. The maximum temperature of the sand, grit and limestone dust, as delivered at the mixing kettle, shall not exceed 375 deg. Fahr. (191 deg. Cent.) and the maximum temperature of the asphalt shall not exceed 350 deg. Fahr. (177 deg. Cent.). The Portland cement shall be thoroughly mixed dry with the WATERPROOFING SPECIFICATIONS 305 sand, grit and limestone dust. This mixture shall then be sprinkled into the hot and molten asphalt until a homogeneous mixture is produced, in which all particles are thoroughly coated with asphalt. The mastic shall be prepared on or close to the work and in amounts not exceeding that quantity which can be laid in one working day. The maximum temperature of any batch of mastic immediately after being mixed shall not exceed 400 deg. Fahr. and the minimum temperature when delivered on the pine floor shall be not less than 300 deg. Fahr. The mastic, containing materials which will become separated by subsidence while the asphalt is in a melted condition, shall be thoroughly agitated before being drawn and while in the supply kettles. Approved methods of agitation shall be used. The contractor shall, at his own expense, provide a sufficient number of accurate, properly constructed thermometers for deter- mining the temperatures of the mastic at all stages of the work. After the mixture has been spread and compressed to a uniform thickness of one (1) inch, it shall be rubbed to a smooth surface with a wooden float. Expansion joints shall be provided where neces- sary. Remarks. The above specifications are used by the Public Service Commission, 1st Dist., State of New York, on all new elevated work of the New York Dual Subway System. The clause calling for the board surface not to be mopped, but covered with a layer of building paper or untreated felt, is at variance with most similar specifications, but has been found necessary to avoid the formation of vapor bubbles on the finished mastic surface. The clause per- mitting the asphalt floor mastic to be made either in a mechanical mixer or by hand, is believed to be a good departure from former limitation to hand mixing. Specifications for Waterproofing Concrete Floors. Thoroughly mix one-half each of D * and tested Portland cement by weight. They should be mixed (dry) until absolutely uniform in color and showing no streaks. Then set aside until ready for use. Lay floor base and topping as usual. The topping should be at least f inch thick and should be made of one part good tested Portland cement and two parts clean, sharp, coarse sand, free from loam and clay. See that the topping is not made too wet, then float well. After the topping is laid and evened, as is usually done, powder or dust the floor with the D cement mixture, using 30 pounds of * These specifications are for the use of a proprietary preparation of finely powdered iron, and designated by D. 306 WATERPROOFING ENGINEERING mixture (15 pounds each of D and cement) to each 100 square feet of topping. Use a small flour sieve for sifting or distributing this mixture over the surface. Allow dust coat to stand about five minutes, then float mixture in well with wooden trowel and tjowel hard. When fairly set, showing no signs of surplus water on surface, trowel a second time until the topping has a smooth, hard finish. After the floor is from twenty-four to forty-eight hours old, cover it evenly with an inch layer of wet pine sawdust or shavings, sand or bags and rewet same twice daily for four or five days. Do not apply the sawdust, etc., until the floor is thoroughly set, as same may adhere to and ruin the finish of the floor. Do not use floor for seven days, or while it is curing. Under no circumstances should heavy trucking be done on a floor less than thirty days old. Cover the floor with boards to assure complete protection. SPECIFICATIONS FOR WATERPROOFING ROOFS The Shingle (Tile) Method. The intention of this specification is to secure a watertight roof by the application of a waterproofing felt layer and an overlying covering of tiles. The roof, prior to the application of the roofing, shall have been constructed in strict accordance with the plans. The roof sheathing should be well laid and tight, all chimneys and walls above roof line completed, and all vent-pipes through the roof properly fastened. The gutters shall be placed in position, extending over the roof sheathing (and cant strips, if same are used), and under the felt and tile at least 8 inches. All valley metal shall be in place, and the width of same must be 24 inches with both edges turned up J inch for the entire length of the valley. This valley metal shall be laid over one layer of felt running the entire distance of the valley. All flashing metal used alongside and in front of dormers, gables, sky- lights, towers, perpendicular walls, also around vent-pipes and chimneys, shall be placed in accordance with the requirements of the tiles. Upon the properly prepared roof, the sheathing shall be covered with one thickness of asphalt or pitch-treated roofing felt, weighing not less than 30 pounds per square. The felt should be laid with 2J-inch laps, and fastened with capped nails. The felt shall be laid parallel with the eaves, and lapped about 4 inches over all valley metal. It shall also be laid under all flashing metal, and turned WATERPROOFING SPECIFICATIONS 307 up about 6 inches against all vertical walls. Upon this felt layer the tiles shall be fastened with copper nails. They shall be well locked together, lay smoothly, and no attempt shall be made to stretch the courses. The tile must be laid so that the vertical lines are parallel with each other, and at right angles to the eaves. The tiles that verge along the hips shall be fitted close against the hip board, and a watertight joint made by cementing the cut hip tile to the hip board with a good elastic cement. Each piece of hip roll shall then be nailed to the hip board, and the hip rolls cemented where they lap each other. The interior spaces of the hip and ridge rolls must not be filled with pointing material. The tiles shall be of the pattern known as (brand of tile and name of manufacturer here mentioned). The tile as specified above must be of shale, hard burned, and of (insert color desired) color. All hip and valley tile shall be cut to the proper angle before burning. Remarks. The above specifications are applicable to pitched roofs only. It does not emphasize the importance of the felt layer underlying the tiles. The one defect of tile roofing is that it is sub- ject to breakage, and when this happens almost sole dependence for continued watertightness (until the tile is replaced) is upon the felt. Therefore the felt should be applied with care, and be of the elastic, built-up, membrane type, that is, consist of at least two plies cemented and properly nailed down. The grade and hardness of the pitch or asphalt used, as binder, must also be considered. A good feature is that it permits the selection and use of many patterns of tile. Composition Roofing Method. (A) Over Board Sheathing* Lay one (1) thickness of sheathing paper or unsaturated felt weigh- ing not less than five (5) pounds per one hundred (100) square feet, lapping the sheets at least one (1) inch.. See Fig. 113. Over the entire surface lay two (2) plies of tarred felt, lapping each sheet seventeen (17) inches over preceding one, and nail as often as is necessary to hold in place until remaining felt is laid. Coat the entire surface uniformly with coal-tar pitch. Over the entire surface lay three (3) plies of tarred felt, lapping each sheet twenty-two (22) inches over preceding one, mopping with coal-tar pitch the full twenty-two (22) inches on each sheet, so that in no place shall felt touch felt. Such nailing as is necessary shall be done so that all nails will be covered by not less than two (2) plies of felt. * This specification should not be used where roof incline exceeds three (3) inches to one (1) foot. 308 WATERPROOFING ENGINEERING FIG. 113. Details of Built-up Slag Roof over Board Sheathing. WATERPROOFING SPECIFICATIONS 309 Spread over the entire surface a uniform coating of pitch, into which, while hot, embed not less than four hundred (400) pounds of gravel or three hundred (300) pounds of slag to each one hundred (100) square feet. The gravel or slag shall be from one-quarter (f) to five-eighths (f ) inch in size, dry and free from dirt. The roof may be inspected before the gravel or slag is applied by cutting a slit not less than three (3) feet long at right angles to the way the felt is laid. All felt and pitch shall bear the manufac- turer's label. (B) Over Concrete.* 1. Coat the concrete uniformly with hot pitch, see Fig. 114. 2. Over the entire surface lay two (2) plies of tarred felt, lapping each sheet seventeen (17) inches over preceding one, mopping with coal-tar pitch the full seventeen (17) inches on each sheet, so that in no place shall felt touch felt. 3. Coat the entire surface uniformly with pitch. 4 and 5. Same as for waterproofing roofs over board sheathing. Remarks. The above specifications are equally applicable to roofs waterproofed with asphalt-treated felt and asphalt binder. For best result, with built-up roofings, both the coal-tar pitch and the asphalt must be carefully selected, as other than the best grades of these materials are very vulnerable to the weather. The Tin Roofing Method, f All of the tin used for roofing all parts of a building shall be tinned iron sheets, which shall be stamped with the brand and thickness on each sheet. All tin used for standing seam roofing shall be ICt thickness, 14 by 20 inches, applied with the 14-inch face parallel to the eaves, forming seams with a double lock. All tin for standing seam roofing shall be put together in rolls with the cross seams formed and soldered, same as specified for flat seam roofing. All standing seam roofing shall be fastened to roof with 2-inch wide tin cleats, spaced 8 inches apart, with cleats locked into seams, and each cleat fastened with two 1-inch barbed wire nails. All tin used for flat roofing shall be 1C thickness, 14 by 20 inch size, using flat seams, with f-inch lock. Flat seam roofing should * This specification should not be used where roof incline exceeds three (3) inches to one (1) foot, and when incline exceeds one (1) inch to one (1) foot, the concrete must permit of nailing or nailing strips must be provided. t Richey's " Building Mechanics' Ready Reference." t Plates are made in two weights, 1C and IX. The 1C is No. 30 gauge, and weighs 0.5 pound to the square foot. The IX is No. 28 gauge, and weighs 0.625 pound per square foot. Either grade is suitable for either flat or standing seam roofing. 310 WATERPROOFING ENGINEERING .Pitch Pitch* Felt Felt Pitch^ Felt Pitch Felt FIG, 114. Details of Built-up Slag Roof over Concrete Slab. WATERPROOFING SPECIFICATIONS 311 be made up and soldered in the shop in long lengths, which must be painted on under side with one coat of paint and allowed to dry before applying to the roof. All flat-seam roofing shall be fastened to roof with 2-inch wide flat tin cleats, spaced 8 inches apart, with cleats locked into seams, and each cleat nailed to roof with two 1-inch barbed wire nails. When the rolls of tin are laid on roof the edges shall be turned up \ inch at right angles to roof, when the cleats shall be installed. Then another course shall be applied with J-inch upturned edge, the adjoining edges shall be locked together, and the seam so formed shall be flattened to a rounded edge and well soldered and soaked in. All valleys shall be formed with flat seam roofing, using 14 by 20 inch sheets laid in the narrow way, with cross seams put together and well soldered, same as specified for flat roofing. All flat seams throughout the roof, including such other parts as may need soldering to make perfectly watertight, shall be soldered with best grade of guaranteed half-and-half solder (half tin and half lead), using nothing but rosin as a flux. Not less than 2 pounds of solder shall be used per square on standing seam roofing, and not less than 8 pounds per square on flat seam roofing, all to be well sweated into the joints. All rosin used in soldering must be carefully cleaned off from all surfaces before any paint is applied to the tin. All tin shall be painted one coat on concealed or under side, as heretofore specified, and two coats on all exposed surfaces: the first coat shall be given four weeks to dry before the second coat is applied. All paint shall be applied with hand brushes and well rubbed in. Litharge only shall be used as a drier. No patent drier or turpen- tine is to be used. The first coat on upper surface shall be applied as soon as laid, and the tin must not be permitted to rust before painting. Specification for Waterproofing Railroad Station Roof.* All roofs in connection with the station buildings shall be made absolutely watertight and weatherproof with (name of manufacturer) " Built-up Asbestos Roofing " or equal thereto. The asphalt shall be (name of brand) or equal thereto and shall be applied sufficiently hot to flow freely. The felt shall be asphalt-saturated asbestos felt (name of brand) or equal thereto. The parapet walls, plumbing pipes, smoke pipes, etc., to a height of not less than 4 inches, the lower edge of the main roofs and all * New York Municipal Railway Corporation, Brooklyn, N. Y. 312 WATERPROOFING ENGINEERING roofs at the walls and pipes to a width of not less than 12 inches shall be thoroughly mopped with asphalt and therein, while it is still hot, shall be embedded one thickness of felt to which a second thickness of felt shall be thoroughly wiped with hot asphalt. The two thicknesses shall be not less than 4 inches high on the walls and pipes nor less than 12 inches wide on the roofs and shall be applied before the flashings and roof boxes are set in place. After the copper flashings and roof boxes have been set and the leaders connected, the surface of the roofs shall be covered with not less than three thicknesses of felt laid 10 J inches to the weather, thoroughly embedded and wiped down in hot asphalt and well wiped to the flashings and leader boxes, the felt to be rolled close behind the mop so that no missing of hot asphalt can possibly take place. The entire surface shall be finished to a smooth, even surface with a heavy coat of (name of manufacturer) " Asphalt Roof Coating " or equal thereto. All flashings and cap flashings in any way required to make the entire work absolutely weathertight shall be furnished as a part of the work under this section. The' flashings, cap flashings, and roof boxes shall be made of 16- ounce cold rolled copper except the flashings and cap flashings to the smoke pipes which shall be 20-ounce cold rolled copper. The mason shall be furnished the cap flashings to be built into the concrete; -these are to be 8 inches wide and built 2 inches into the concrete with the built-in edge turned up \ inch; they are to be set not less than 8 inches above the roof and where stepped should be lapped not less than the height of the step. The flashings shall be turned 4 inches under the roofing and shall be of sufficient width to fit closely under the built-in portion of the cap flashings ; they are to be set after two layers of roofing have been applied as hereinbefore specified, and the cap flashings are to be bent down and heavily tinned and soldered at all corners and angles. All soldering in any way required to make the entire work abso- lutely watertight and weatherproof, shall be done in the neatest and best manner. The copper which is to be soldered shall be heavily tinned and all joints shall be thoroughly sweated and neatly soldered over and all superfluous solder shall be neatly removed. All sheet metal work and roofing shall be delivered at the final completion of the works, clean, whole, perfect, and absolutely water- tight and waterproof. CHAPTER IX PRACTICAL RECIPES AND SPECIAL FORMULAS ORIGIN AND NATURE OF SPECIAL FORMULAS CONSIDERING the many varied purposes and conditions under which the different systems of waterproofing are found serviceable, it is surprising how few are the basic waterproofing compounds in common use. Not more than fifty of such compounds are in the market. Of these compounds the integral system claims about 30 per cent, the surface coating system about 40 per cent, and the membrane and mastic systems about 30 per cent. The grouting and self-densified processes are not considered in this connection because they require, besides a good grade of material, only scientific manipu- lation for successful work. The general nature of most of the basic compounds is discussed in Chapter V. On the other hand, of the special waterproofing compounds there are at least several hundred. The nature of these, of course, is in most instances kept as a trade secret. Still, from time to time, some chemists and engineers dis- cover or invent useful waterproofing compounds or new processes for utilizing old compounds. These are often published in the technical press of both the chemical and engineering professions. Government chemists, and engineers in particular, are very resource- ful and liberal in this regard. The United States Department of Agriculture, the Department of Interior and the Department of Commerce and Labor, publish annually scores of bulletins and tech- nical papers some of which are replete with valuable information, suggestions, and tests on new and old waterproofing methods and materials,* which are often distributed free and never for more than cost. These publications are regarded with great favor and au- thority in the waterproofing industry; and well they may be, for they are always unbiased, truthful and practical, the only adverse criticism * As illustrations of the types of these papers, see Bulletin No. 230 of the Office of Public Roads, U. S. Department of Agriculture; Technologic Paper No. 3 of the Bureau of Standards, Department of Commerce and Labor; Bulletin No. 329 of the U. S. Geological Survey, Department of Interior. 313 314 WATERPROOFING ENGINEERING being occasioned, in a few instances, by the occasional incompleteness of the data and the results based thereon. Waterproofing formulas, like paint formulas, are often individual secrets, kept by the discoverer from the world for his commercial advantage. Like most paints, waterproofing compounds, unless investigated by the most competent chemists, often baffle chemical analysis, and more often chemical synthesis. The method of com- bining, or the process of manufacturing most waterproofing com- pounds, is more difficult and kept more secretive than is the knowl- edge of the constituent ingredients. Of course, where compounds are patented, a certain amount of information is divulged to the public, but the patent prevents the unlicensed use of the compounds. This facilitates and sometimes encourages the marketing of imita- tions, better or worse, which the purchaser must guard against by careful investigation. In compiling this chapter the author has freely availed himself of all the above-mentioned sources with due acknowledgment. In- cluded also are formulas and practical recipes derived from personal experience and the experience of a few associates in both the chemical and engineering professions. In making compounds from any of these formulas, care and judgment are essential to success. They are arranged under the general heads of Masonry Treatments, Treatments for Tanks, Floor Treatments, Roofings, and Water- proof Cements, but no strict divisions were attempted. MASONRY TREATMENTS Waterproof Mortar. For masonry joints: equal parts of sand and cement with sufficient water to form a plastic paste produces a very waterproof mortar; for surfacing and stucco work a 1 : 2 mortar is very efficient provided it is allowed to dry very slowly. A mixture consisting of one-sixth underburnt and one-sixth well- burnt powdered brick, one-third slaked lime, and one-third sand, will make a dense, waterproof mortar. Dampproof Coating Compounds for Masonry. An easily made and applied coating for dampproofing purposes consists of about 20 per cent, by weight, of paraffin (melting-point between 104 and 122 deg. Fahr. (40 and 50 deg. Cent.) dissolved in 80 per cent of a petroleum oil mixture. This mixture may be made of about 45 per cent benzene, 25 per cent wood turpentine and 30 per cent kerosene. PRACTICAL RECIPES AND SPECIAL FORMULAS 315 A similar compound can be made by mixing about 5 per cent, by weight, of paraffin, 5 per cent alumina resinate, 45 per cent benzine and 45 per cent kerosene. A good surface-coating compound can be made in the form of a thin paste by mixing with water to the required consistency, about 96 per cent by weight of powdered cast iron and 4 per cent of sal- ammoniac. This paste should be carefully applied, preferably in two coats with a stiff brush, as it is necessary for it to adhere to the concrete to be effective. A solution of water glass (about 5 per cent) when applied as a coating to a surface containing lime will form a hard, impervious finish by the chemical action between the lime and the alkaline silicate or water glass. On concrete it is rather difficult to accomplish this action because the lime is not free to get at. Surface Coatings for Masonry. A liquid, waterproof, surface coating, consists of the following formula: 70 per cent of asphalt, 30 per cent of turpentine substitute or other petroleum product. The petroleum product should be added while the asphalt is hot. The mixture can then be applied cold with a brush. It may also be mixed as an integral compound in mass concrete or mortar in quanti- ties ranging between 5 and 10 per cent by weight of cement. A plastic form of waterproof surface coating may be made as follows: Pine creosote oil, about 40 per cent; fiber asbestos, 30 per cent; pine pitch 30 per cent. The pitch and oil must be cooked together and the asbestos added while the mixture is hot. This material is viscous enough to be troweled on the masonry and can be applied to a wet or dry surface. A durable, tough, and elastic compound that can be used for both roof coverings and flashings consists of a good grade of refined asphalt mixed with from 5 to 25 per cent of stearine pitch. The proportion is governed by the consistency desired and the melting- point of the asphalt. The following surface coating will remain plastic and elastic for a long time. It is applied cold, by troweling on the surface to be waterproofed. Hot elaterite, about 85 per cent; mixed with about 15 per cent of castor oil or cotton-seed oil. If a little gutta percha is added, the compound is considerably improved. An impervious surface coating for industrial concrete wash basins, etc., can be obtained by rubbing the inside surface with a cement brick just after removing the forms. This brick can be made of a 1 : 2 mortar. While rubbing, the concrete surface should be sprinkled constantly with water; this will form a paste over the surface and 316 WATERPROOFING ENGINEERING tend to fill the pores. Two or three rubbings in this manner will produce a very impervious surface. Dampproofing for Brick Walls.* In applying the following com- pounds all dampness of the wall must first be allowed to dry up as much as possible. The process of dampproofing then proceeds as follows: One coat of boiled linseed oil is first applied over the wall and all joints. All holes are then puttied up with a paste composed of pure linseed oil and whiting, colored with fine brick dust or Vene- tian red. Venetian red, thinned with equal parts of boiled linseed oil and turpentine, is then applied as a second coat. Finally a third coat of red oxide and drier is applied as a finish coat. The color may be changed from a red to any desirable tint using white lead as the base, tinting with oil color to suit. Another formula is as follows: Venetian red mixed with skim milk (casein) . The action of the lime base in the Venetian red will make the curd of the milk insoluble in water. Should the Venetian red be free from lime, then lime water, whiting or quick lime must be added to the milk before mixing the Venetian red with it. (To ascertain whether the Venetian red contains whiting or lime, a portion of it is dropped in some commercial sulphuric acid, and if the red powder does not effervesce, lime in the form needed is not present, and the aforesaid alkaline addition must be made.) If the color is to be waterproofed, however, to each gallon thereof must be added one-half gallon boiled linseed oil and well stirred. Both these mix- tures, when properly made, will not wash off for years. A water-shedding, dampproofing compound for brick and con- crete masonry may be made by mixing about 80 per cent of kerosene with 10 per cent of acetone and 10 per cent of creosote. This com- pound should be applied with a brush and thoroughly rubbed in on a clean surface. It tends to fill the pores of the masonry and shed water from the surface. A damp-resisting paint can be made by mixing, until solution is effected, melted Manila or Copal gum with linesed oil or China wood oil ; this mixture is then dissolved in benzol or naphtha. It is applied with a brush in several coats. For a top coat it is well to evaporate more of the gum and add more of the drying oil. The compound may also be mixed with any desired pigment. Stone Preserving Compositions.! With the following liquid compound it is possible to preserve a brownstone front against the * " 739 Paint Questions Answered," published by The Painters' Magazine of New York in 1904. t " Scientific American Cyclopedia of Formulas," 1915. PRACTICAL RECIPES AND SPECIAL FORMULAS 317 weather without altering its appearance, its stony aspect not being altered by the liquid after it has penetrated and dried. Ten gallons of thinning liquid, such as fish oil, or linseed oil, mixed with 2 pounds dry zinc white, and 5 pounds powdered brown oxide. Before apply- ing the liquid, the surfaces should be brushed clean with wire brushes. Paraffin is the best material for rendering natural stones, con- crete and brick-work impervious to water. If dissolved in the pro- portion of one-third paraffin and two-thirds kerosene, it remains soft longer and penetrates the stone further. Paraffin is unaltered by weather or acids. If carefully melted in, it does not change the color of the stone; it simply deepens the color like water. It is cheap, easily applied and efficacious. It is most easily applied in hot weather. Leaks in concrete walls can be stopped by enlarging the cracks and applying a hot mixture of Portland cement and caustic soda, which sets almost instantly. The concrete around the leak should be cut out so that the hole or groove is larger at the base than at the surface. The hot paste is then applied rapidly with gloved hands, first against one side of the cavity and then successively around the sides of the cavity until it is completely closed. The soda should be mixed with little water and be boiling hot when the cement is added in amounts enough to make a stiff paste.* TREATMENT FOR TANKS Preserving Concrete Tanks from Cemmercial Liquids, f The following fluids may be stored in tanks made of plain dense con- crete of 1 : 2 : 4 mix without causing any deterioration in the con- crete: Menhaden oil, linseed oil, rosin oil, 4 per cent caustic soda solution, tanning solution, and sauerkraut. For safely storing sulphite liquor and cider vinegar in concrete tanks, the only satisfactory method found to protect the concrete from disintegration is by applying a surface coat of an oil-gilsonite compound. This compound is made by dissolving 100 parts, by weight, of gilsonite in 250 parts of turpentine, and adding 5 parts of neutral petroleum oil. At ordinary temperatures, with frequent stirring, about twenty-four hours will be required for a perfect * Engineering Record, March 3, 1917. t Results of a series of tests, extending over a period of more than a year, made for the Portland Cement Association to determine the effects of commercial liquids on concrete tanks, by the Institute of Industrial Research, Washington, D. C, Reported in Engineering Record, Vol. 74, No. 16, October 14, 1916. 318 WATERPROOFING ENGINEERING solution. Two coats of this mixture, should be applied with a brush to the inner surface allowing at least twenty-four hours for each to dry. For safely storing molasses in concrete tanks, in a manner so that neither the molasses nor the concrete is injured, the inner surface should be well protected with two coats of Bakelite varnish. Con- centrated brines may similarly be stored in concrete tanks by coat- ing the inside with two layers of the above-mentioned oil-gilsonite compound between which is placed an asphalt-treated fabric. Upon this one-ply membrane should be placed a 1 : 2 cement mortar coating, and the latter painted with two coats of Bakelite. Cement to Resist Benzine and Petroleum.* Gelatine mixed with glycerine yields a liquid compound when hot, but which solidifies on cooling, and forms a tough, elastic substance, having much the appearance and characteristics of India rubber. The two substances unite to form a mixture absolutely insoluble in pe- troleum or benzine, and the problem of making casks impervious to these fluids may be solved by brushing or painting them on the inside with this compound. Water must not be used with this compound. Wooden and Iron Tanks Made Watertight. Wooden tanks should first be drained well and permitted to dry out thoroughly. Then the hoops must be tightened and the inside be given a coat or two of hot paraffin oil or melted paraffin wax, applied while hot. This done, the iron or steel hoops should receive a coat of red lead and the outside of the tank one or two coats of good, elastic oil paint of any color desired, f Joints in iron tanks that have opened up can be sealed effectively by calking with proper tools (see Fig. 115). This operation consists FIG. 115. Calking Operation with in beating down the edges of the Hand or Pneumatic Calking metal against the face of the opposite Tool s- plate. The round -nosed calking tool is usually employed in modern practice. A more effective way of calking is with lead wool hammered * " Scientific American Cyclopedia of Formulas," 1915. t " 739 Paint Questions Answered," published by The Painters' Magazine of New York in 1904, PRACTICAL RECIPES AND SPECIAL FORMULAS 319 into the joint. Coating the outside of the joint with a thick applica- tion of a hard, tough asphalt or a sealing w.x of a similar nature, is also effective except for hot-water tanks. Both of these materials must be applied on a properly cleaned surface. A preserving varnish for wood and metal tanks is easily made by mixing three parts of pure asphalt (solid or liquid variety) with four parts of boiled linseed oil and from fifteen to eighteen parts of turpentine. FLOOR TREATMENTS Concrete Floor Hardener. The following formula is used for hardening concrete floors: Powdered pig iron mixed with about 2 per cent, by weight, of salammoniac. This mixture may be floated on a partially set concrete surface which is thereby hardened for a depth of a fraction of an inch, but it is not very durable. The mixture may also be combined with Portland cement in equal proportions by weight to form a mortar that is applied, about f inch thick on a clean surface of concrete. This mortar coat will create a dense and impervious floor if properly and carefully applied. A serious objection to the use of this formula is the frequent discol- oration of the surfaces treated due to the uneven distribution and oxidation of the powdered metal. Wooden Floor and Flooring Made Watertight.* Flooring may be made impermeable by being painted with a solution of paraffin wax dissolved in kerosene. The coat will last for about two years. ROOFINGS Roofing Paner.f Old newspapers or sheets of wrapping paper in good condition may be converted into waterproof roofing material by coating them with hot coal-tar pitch or asphalt with a brush, and uniting two or more sheets. These mats can then be applied to a roof, shingle fashion, creating a cheap but good roofing for sheds and shanties and for temporary, small constructions. Roofing Cement. A waterproof bituminous cement for binding roofing felt, one that will not flow readily in the summer's heat, may be made by mixing one part of burnt lime (but not slaked) with seven parts of coal tar, both by weight. The lime is powdered * " Scientific American Cyclopedia of Formulas," 1915. t " Scientific American Cyclopedia of Formulas," 1915, 320 WATERPROOFING ENGINEERING and sprinkled into the hot tar, with which it mixes intimately. The mixture hardens on cooling and therefore must be applied hot. WATERPROOF CEMENTS Adhesives. The following waterproof cements can be made with but little difficulty or previous experience:* (1) Shellac, 4 ounces; broax, 1 ounce; boiled in a little water until dissolved, and concentrated by heat to a paste. (2) Carbon bisulphide, 10 parts; oil of turpentine, 1 part; mixed with as much gutta-percha as will readily dissolve in the mixture. (3) Tar, 1 part; tallow, 1 part; fine brick dust, 1 part; the latter should first be warmed over a very gentle fire; the tallow added, then the tar, and the whole thoroughly mixed. This com- pound must be applied while hot. (4) Good quality gray clay, 4 parts; black oxide of manganese, 6 parts; lime, reduced to powder by sprinkling with water, 90 parts; the combination mixed, calcined and powdered. (5) A very strong cement, but one which requires to be applied directly after being made as it sets very quickly, is the following: Quicklime, 5 parts; fresh cheese, 6 parts; water, 1 part. The lime is slaked by sprinkling with water; thereupon it is passed through a sieve, and the fresh cheese is added. The latter is prepared by curdling milk with a little vinegar and removing the whey. (6) A cement adapted for joining stone, metal, wood, etc., can be made as follows: Fresh curd, as before, 1 pert; Roman (natural) cement, 3 parts. This must be well mixed and quickly applied. (7) A cementing paste composed of hydraulic lime and dissolved water glass will withstand the action of heat as well as water. (8) Glue, 1 part; black rosin, 1 part; red ochre, } part; mixed with the least possible quantity of water. (9) Glue, 4 parts; boiled linseed oil, 1 part; oxide of iron, 1 part all by weight and well mixed together. (10) A good cement is made by mixing about 7 parts of litharge and 93 parts of burned clay or whiting together reduced to a fine powder and made into a paste with linseed oil. f (11) A cement may be formed by mixing into a paste freshly calcined oyster shell lime, well sifted and ground fine with white of egg- * " Scientific American Cyclopedia of Formulas," 1915. t " 739 Painters Questions Answered," Painters' Magazine, New York, PRACTICAL RECIPES AND SPECIAL FORMULAS 321 (12) Four parts, by weight, of shellac boiled with 1 part, by weight, of borax in water until the shellac is dissolved. This mix- ture should be kept boiling until it is of a paste-like consistency. To use this paste it must be heated and applied with a clean brush. (13) For many odd and varied purposes, commercial sealing wax will prove a very good waterproof cement. It consists of hard resinous materials, such as lac, with some form of pigment, as ver- milion. Beeswax alone or mixed with a fine mineral dust can also be used to advantage. Waterproof Cement for Leather.* A waterproof cement for leather is prepared by dissolving gutta-percha, caoutchouc, benzoin, shellac, mastic f and similar materials, in some convenient solvent like carbon disulphide, chloroform, ether or alcohol. The best solvent, however, in the case of gutta-percha is carbon Ksulphide, and ether for mastic. The most favorable proportions are as follows: Gutta-percha 200 to 300 parts to 100 parts of the solvent, and 75 to 85 parts of mastic to 100 parts of ether. From 5 to 8 parts of the foimer solution mixed with 1 part of the latter and boiled in a water bath to any consistency desired makes a good cement. Waterproof Compounds for Textile Fabrics. { Textile fabrics can be made waterproof by successive impregnations with a solution of soap and a solution of alum. Or, by successive impregnations with a solution of alumina sulphate (made by dissolving in ten times its weight of water), and a soap solution composed of 1 ounce light- colored rosin, 1 ounce of crystallized soda, boiled together in 10 ounces of water until dissolved. Also by impregnation, first with a solution of ammoniacal cupric sulphate of 10 deg. Baume at 77 deg. Fahr. (25 deg. Cent.) then, with a solution of caustic soda of 20 deg. Baume. Increased impermeability will be obtained by using sulphate alumina in place of caustic soda. To waterproof one side of cloth, it must be imbued on the wrong side with a solution of isinglass, alum, and soap in equal parts each dissolved separately, and made into a solution with- sufficient water. Another method is to impregnate the fabric with hot, molten paraffin. Sheets of canvas or tarpaulins may be made waterproof by paint- ing the surfaces with or clipping them in a mixture of coal tar, gasoline and a good Japan drier in the proportion of 5 : 1 : 1. * " The Manufacture of Varnishes and Kindred Industries," by Livache and Mclntosh, Vol. 3, p. 376. f A form of resin secreted by shrubby trees cultivated on the island of Chios in the Greek Archipelago. J " Scientific American Cyclopedia of Formulas," 1915, Munn & Co., Inc. 322 WATERPROOFING ENGINEERING Waterproof Compound for Drawing and Tracing Sheets.* Drawing and tracing sheets can be made waterproof, so that they may be used in wet places, as in mines, for instance, by the applica- tion, to one or both sides, of a preparation composed of rubber and benzol. The preparation is made by dissolving a quantity of pure rubber in benzol and thinning down with more benzol to any desired consistency. The rubber first swells enormously and in about twenty-four hours is ready for use. For use as a waterproof adhe- sive the solution should be fairly stiff. Only the pure gum rubber is satisfactory for this purpose. * Engineering News-Record, Vol. 81, No. 13, September 26, 1918, p. 597. CHAPTER X WATERPROOFING APPLIED WATERPROOFING applied forms an important part of waterproof- ing engineering and also a very interesting one. It describes accom- plishment in the field. Chemical analyses and physical tests of waterproofing materials are important but they are, after all, mostly accelerated tests. Service is the real " acid test " for all waterproof- ing materials and their application. The best criterion of the rela- tive merits of the various materials and systems of waterproofing discussed in previous chapters is their efficacy and endurance in service. Many secret and patented compounds and various types of waterproofing cannot be fairly judged in any other way than by their past performences. In fact, certain grades of asphalt have won favor and preferance for waterproofing purposes by no other means than past service. Coal-tar pitch is extensively used for water- proofing underground structures for the same reason. On the other hand, many integral and surface-coating compounds proved their unworth in this manner though apparently successful in the labora- tory. The grouting process of waterproofing is advancing rapidly now only because of its efficiency as proved in service. In this chapter will be found practical instances of each of the six systems of waterproofing previously discussed ; also the standard and special materials used, the methods of application and where possible the degree of success obtained. EXAMPLES OF SURFACE COATING APPLICATIONS Water Storage Works, U. S. Reclamation Service. The storage works and tunnel connected with the Strawberry Valley Project * in the U. S. Reclamation Service are located in the Wasatch Moun- tains at an elevation of 7500 feet, surrounded by mountains, some of which reach an elevation of 10,000 feet above sea level. There is a wide variation in temperature in this vicinity during the entire * Enginerring News, Vol. 73, No. 15, April, 1915. 323 324 WATERPROOFING ENGINEERING year, and the climate is very severe during the winter months, the lowest temperature on record being 50 deg. Fahr. below zero. The snowfall ranges from 10 feet in low years to 24 feet in high years. On account of these conditions of extreme cold, with alternate thaw- ing and freezing, the action of water and frost on concrete that is not impervious is very marked. It was therefore decided to treat the concrete with some sort of preventive against absorption of water by the surfaces exposed. A study was made of the various waterproofing processes in com- mon practice. Because the structures had been completed, and in view of the extraordinary conditions, it was decided to treat the verti- cal surfaces with alum and soap solutions (Sylvester process) and the horizontal ones with paraffin. The alum solution was made by dissolving 2 ounces of alum in 1 gallon of hot water. The soap solution was composed of f pound of castile soap dissolved in 1 gallon of hot water. The paraffin was boiled to rid it of any water content, as the presence of water rendered it hard to apply. Ordinary commercial products were used. The surface to be treated with paraffin was first entirely freed from all moisture, loose concrete, dirt and other foreign substances. The paraffin was then heated and applied to the surface of the concrete with a paint brush and was forced into the pores by flashing the flame of a blow torch over the surface. In the application of the alum and soap (which produces an in- soluble aluminum stearate in the pores and on the surface of the concrete), the surface of the concrete was first prepared in the same manner as for the paraffin treatment. The alum solution was then applied at a temperature of 100 deg. Fahr. with a moderately stiff brush, and was then worked in with a stiff horse-brush. While the surface was still moist from this treatment the hot soap solution was applied in the same manner. One treatment with each solution in the manner described above constituted a coai. If other coats were deemed necessary, they were applied in a manner similar to the first coat, after the preceding coat had been allowed to stand twenty- four hours or more. The work of application was carried on by two men, one applying the solution and the other following and working it in as described above. No actual tests were made to determine the imperviousness of the concrete after treatment, but the structures that were repaired and treated have gone through two severe winters and no further disintegration of the concrete on any part* thereof has occurred. WATERPROOFING APPLIED 325 Gate Houses of Croton Reservoir.* In the New York City Croton Reservoir the face walls of the back bays of gate houses were built of hard-burnt brick laid in cement mortar. A space between the walls 4 feet wide was filled with concrete. The brick walls were 12 inches thick and 40 feet high and impounded water under a head of 36 feet. When the reservoir was first filled and water let into the gate houses, it filtered through the walls to a considerable amount. The Sylvester process for repelling moisture from external walls was used to waterproof the walls of these gate houses. This con- sisted of two washes or solutions for covering the surface of brick walls, one composed of castile soap and water and one of alum and water. The proportions were f pound of soap to 1 gallon of water; and | pound of alum to 4 gallons of water, both substances being perfectly dissolved in the water before being used. The first, or soap wash was applied, at boiling heat, with a flat brush, taking care not to form a froth on the brick work. This wash remained twenty-four hours so as to become dry and hard before the second or alum wash was applied ; which was done in the same manner as the first. The temperature of this wash when applied was between 60 and 70 deg. Fahr. At least twenty-four hours elapsed before a second coat of the soap wash was put on. These coats were repeated alternately until the walls were made im- pervious to water. Four coatings rendered the brick wall imperme- able under a pressure of 40-foot head. The cost was about ten cents per square foot for four coats. Retaining Walls, Rock Island Pailrcad. The retaining walls and abutments on the Chicago track elevation work of the Rock Island Railroad Lines are waterproofed with a coal-tar pitch com- position applied to the back of the walls. The expansion joints of these walls were waterproofed by placing a strip of burlap and felt over each joint and mopped with the same composition. Later observations showed these coatings to be satisfactory. Beaver Park Dam.f The Beaver Park Dam in Colorado is a masonry structure of the rock-fill type. It was made watertight by the application of reinforced concrete facing to its upstream face, as indicated in Fig. 116. This concrete face was placed with no rods or ties to secure it to the rubble face of the dam, as the interstices in the rubble face were depended upon to give sufficient * Abstract of Paper read before the American Society of Civil Engineers by Mr. Wm. L. Deardon, May 4, 1870. t Engineering News, Vol. 73, April 8, 1915. 326 WATERPROOFING ENGINEERING bond between the concrete and the hand-laid wall. The concrete is reinforced horizontally and vertically with wire fabric of diamond mesh, the main wires being No. 4 gauge, spaced 5 inches apart. No expansion joints were provided, and although the concrete face has been exposed to severe temperature conditions, few or no tempera- ture cracks have occurred. The concrete in the lower portion of the wall forming the water face and in the gate tower was of 1:2:4 mixture, the aggregate consisting of crushed trachite, while the upper portion of the wall and tower was made of a mixture consisting of practically equal parts of sand and gravel. Up to a point about 20 feet below the crest, a calcium-oleate waterproofing compound was added to the water used to gauge the mixture. The specifications provided that one part JE1.194 K-16*) H.W.L.E1 185 1 Slope, Rubble Masonry pointed with Cement Mortar SPILLWAY SECTION MAIN SECTION FIG. 116. Sections through Beaver Park Dam Showing Waterproof Facings. of the compound was to be added to an equal amount of water and thoroughly dissolved, after which eleven more parts of water were to be added, and this solution used in mixing the concrete for all 24-inch walls and a somewhat weaker solution for thinner walls. The results obtained by using this compound seemed so unsatis- factory to the engineer, that its use was ordered discontinued, and extra cement was added to the concrete at the same cost, which gave much better results. Queensboro (Steinway) Tunnel. The Queensboro tunnel in New York City (formerly known as the Steinway tunnel), is about 80 feet below ground-water level in water-bearing rock. In its reconstruction the stations were enlarged and waterproofed. It was proposed to waterproof one very large station by the membrane system, and two remaining small ones by the surface-mortar-coating system. The membrane was to consist of six plies of treated fabric laid in coal-tar pitch and applied over the arch as shown in Fig. 117. For lack of head room and on account of the great expense involved in securing this head room the membrane was not installed. In- WATERPROOFING APPLIED 327 stead, a waterproofed surface mortar-coat was applied. In 1916 the two small stations and a portion of the very large station were treated with a 1-inch mortar coat, waterproofed with a proprietary liquid compound composed of a mixture of calcium chloride and a Proposed 6 ply waterproofing membrane, abandoned for lack of headroom. Pay line for concrete. Net line FIG. 117. Typical Half-section through Station. carbohydrate and applied with a trowel on the inside of the arch and sides. This surface mortar coat contained about 7 per cent of the waterproofing liquid (added to the gauging water) was easy to apply but troublesome after application, required repairing, and even then it did not remain entirely impervious thereafter. In 1917 the remain- 328 WATERPROOFING ENGINEERING ing and major portion of the large station was waterproofed by the application of a similar mortar coat J inch thick, made of a 1:2 mixture containing an alum-soap paste compound mixed in the pro- portion of one part paste to fifteen parts of gauging water. As a result of this work the leakage was markedly reduced. Some blast- ing in the vicinity may have contributed to the difficulty of making these waterproofed mortar coats entirely impervious. Nashville Water Works Reservoir. In repairing and water- proofing the Nashville Water Works Reservoir * precaution was taken against cracks opening at the junction of the new masonry with the old, by using a flexible U-shaped, heavy, sheet-lead stop joint. This was inserted by cutting a dove-tail groove in the con- crete core from bottom to top of the ends of the old wall, and by anchoring one end of the lead joint therein with rich concrete in advance of the new masonry, but leaving the other end free. The fold in the joint was protected with tar felt to assure free movement, and the new masonry was built around the free end thereof. This contrivance was simple, effective, of very little trouble, and inex- pensive. See Fig. 118. For waterproofing the interior face of the walls, the cement gun was used and the work proceeded in the fol- lowing manner: The walls were first thoroughly cleaned of all scale and foreign matter by means of pneumatic-hammer chisels so as to afford sound stone faces for the mortar. By the same means the old mortar joints were gouged out to depths varying from 1 to 3 inches for the cement-gun mortar. The walls were therl sinrl-blasted and sprayed immediately in advance of the cement- gun, resulting in clean, sound, stone faces and mortar joints. The cement-gun mortar, composed of one volume of Portland cement to three volumes of clean sand, followed right behind the sand blasting and spraying before the walls could dry. The whole interior of the walls, including the new masonry, was thus coated and made watertight. Before laying the asphalt-treated felt membrane used to water- proof the floor, the old concrete floor was carefully cleaned and flushed off with a powerful stream, and all loose scale removed. All rough places and sharp depressions were then filled and brought to a smooth plane with rich cement mortar. After thoroughly drying, the floor was well painted with a priming coat of asphalt dissolved in naphtha. This was followed with a very heavy coat of asphalt heated to a temperature of about 325 deg. Fahr. The asphalt- treated felt followed closely behind this mop coat, in alternate layers * Engineering News, Vol. 73, May 6, 1915. WATERPROOFING APPLIED 329 of felt and heavy mop coats. Each layer of felt was carefully rolled down before the succeeding coat and next layer of felt were applied, care being taken to squeeze out all the air bubbles. The felt over- 6 Ply Limestone facing stones laid ia Portland Cetneut, mortar to match exist- ing wall Broken stone around i" Vit. drain laid with open joints, slope 1:100 All reinforcing rods to Theoretical inside ;o /Theoretical in J line of wall I i" A^////^/ (Theoretical inside VJ Hne of wall 71., / '//////. 30. toC. _ g Asphalt Is SECTION SHOWING WEDGE JOINT AT OUTSIDE WALL SECTION SHOWING JOINT AT DIVISION WALL FIG. 118. Showing Waterproofing Details of Nashville Reservoir Wall and Floor. lapped and broke joints 3 inches on longitudinal edges and 10 or 12 inches on ends. Five layers of the felt were employed, ending with a heavy mop coat all over the top. 330 WATERPROOFING ENGINEERING The reservoir, repaired as above described, was for all practical purposes watertight for over two years. In May, 1916, it was emptied during the warm weather for cleaning. During the process of cleaning and removing the mud out of the basin, the cement-gun mortar was exposed to the sun's rays, and badly checked and cracked. These defects were corrected by cutting the mortar out of all visible checks and cracks to the original masonry. These cut-out cracks were then rilled with cement gun-mortar. A water curtain was then provided to sprotect the walls from the effect of the sun's rays. This was accomplished by means of a perforated pipe kid around the inner edge of the top of the wall, from which the water trickled down and spread over the mortar lining. By these means, the basin was again made watertight. The Hudson-Manhattan Tunnels.* Wherever work was executed by open-cut methods on the Hudson-Manhattan Tunnels, between New York and New Jersey, the" structure was waterproofed with treated fabric and coal-tar pitch applied in the usual manner, making a complete envelope around it. As the greatest part of this work, however, was executed by tunnel methods this manner of waterproof- ing was not feasible except in small portions of the work. The method adopted, therefore, was invariably to grout with Portland cement in the rear of the cast-iron ring lining or concrete lining, and in the majority of cases this application 'answered the purpose of making the tunnels perfectly watertight. Owing to the impervious- ness of neat cement this was the only waterproofing adopted on the coffer-dam walls of the Church Street terminal and approaches. In the iron-lined sections of the tunnel all joints of the plate segments were made watertight by grommetting the bolts with flax and red lead under the bolt washers, and calking the spaces between the joints of the plate lining with a thread of lead wool, followed up and supported with rust-joint cement. Throughout the concrete work, waterproofing was done by plastering the internal and exposed surface with one of the usual types of waterproofing compounds mixed with neat Portland cement and applied with a trowel, this method answering admirably in a majority of cases. At the same time, in persistent leaks, it was found necessary to cut right back into the concrete and expose the voids and then reconstruct such portion of concrete with a rich mixture of cement. As a general rule, for waterproofing of concrete work a rich mixture of cement in * " Subways and Tunnels of New York," by G. H. Gilbert, Lucius I. Wight- man and W. L. Saunders. WATERPROOFING APPLIED 331 the concrete with thorough and efficient ramming answered the purpose and constituted the only waterproofing used. Reinforced Concrete Standpipe. At Attleboro, Mass., a large reinforced concrete standpipe, 50 feet in diameter, 106 feet high from the inside of the bottom to the top of the cornice, and with a capacity of 1,500,000 gallons, has been constructed and is in the service of the waterworks of that city. The walls of the standpipe are 18 inches at the bottom, and 8 inches at the top. A mixture of 1 part cement, 2 parts sand, and 4 parts broken stone, the stone varying from J inch to 1| inches, was used. The forms were constructed, and the con- crete placed, in sections of 7 feet. When the walls of the tank had been completed, there was some leakage at the bottom with a head of water of 100 feet. The inside walls were then thoroughly cleaned and picked and four coats of plaster applied. The first coat con- tained 2 per cent of hydrated lime to 1 part of cement and 1 part of sand; the remaining three coats were composed of 1 part sand to 1 part cement. Each coat was floated until a hard, dense surface was produced; then it was scratched to receive the succeeding coat. On filling the standpipe after the four coats of plaster had been applied, the standpipe was found to be not absolutely watertight. The water was drawn out; four coats of a solution of castile soap and one of alum (Sylvester process) were applied alternately, and under a 100-foot head, only a few leaks then appeared. Prac- tically no leakage occurred at the joints; but in several instances a mixture somewhat wetter than usual was used, with the result that the spading and ramming served to drive the stone to the bottom of the batch being placed, and, as a consequence, in these places, porous spots occurred. The joints were obtained by inserting beveled tonguing pieces, by thoroughly washing the joints and covering them with a layer of thin grout before placing additional concrete. EXAMPLES OF MEMBRANE APPLICATIONS East View Tunnel.* Tunnels are usually not waterproofed by the membrane system because of the difficulty of applying the membrane and making it adhere to the arch. Therefore the grouting process is generally used. The surface-coating system can also be used successfully, but the materials must be carefully chosen and applied. But it may be impossible to employ either of these systems with good results because of the presence of disintegrating agents in the soil * New York Board of Water Supply Report 1916, p. 135. 332 WATERPROOFING ENGINEERING or rock through which the tunnel passes. Under such condition the membrane system is best used, and a case in point is the following: A 1700-foot portion of the East View Tunnel of the New York Catskill Aqueduct was built in rock containing iron pyrites from which the compound, sulphuric anhydride (SO p.) is dissolved by the ground water, forming sulphuric acid. This solution, percolating through the seams of the rock, attacked the limestone aggregate of the concrete and also the cement sufficiently to cause disintegration in the concrete lining of the tunnel. It was therefore decided to waterproof this section by means of a 3-ply bituminous membrane. The method pursued in doing this work was as follows: To the face of the partly disintegrated lining was nailed, shingle fashion, No. 28 gauge sheet iron. This acted as a shedding surface for the drip and a dry-ply upon which the membrane was applied. The fabric, which was 3 feet wide was cut up into 6-foot lengths preparatory to applying same. Hot asphalt was mopped on the sheet iron over an area equal to about half the width of the 6-foot strips. Then a strip of fabric was applied (transversely to the center line of the tunnel) and pressed into the binder. The other half of the strip was similarly applied. The second and third plies were laid up like- wise, the top ply receiving a final coating of asphalt on its entire surface. Within and against this membrane a brick wall, 1 foot thick, was built completely around the waterproofing. On the completion of this work the cracks and crevices in the semi-disintegrated concrete, and also the space between the sheet iron and the concrete lining, were grouted. For this purpose 3-inch pipes were attached to the sheet iron and waterproofed around the joint before the brick wall was built. The results obtained by this method of waterproofing the tunnel proved entirely satisfactory. The asphalt used on this work was a Mexican refined asphalt with a penetration of .55 cm. at 77 deg. Fahr. The fabric was a saturated cotton drill. The asphalt was heated in the tunnel in a rectangular kettle whose source of heat was a battery of gasoline torch burners under it. The gas, contained in a tank under pressure, consisted of about one part gasoline to four parts kerosene. Long Island Railroad Subway. The Atlantic Avenue section of the Long Island Railroad * in Brooklyn, N. Y., is built of con- crete (see Fig. 119). The 5-foot arches, forming the roof are sup- ported by transverse I-beams. This roof was waterproofed in the following manner: After the concrete had thoroughly set and been well dried out by the sun, the upper surface was swabbed over with * " Modern Tunnel Practice," by D. McNeely Stauffer. WATERPROOFING APPLIED 333 hot, medium-hard, coal-tar pitch such as will soften at a temperature of 60 deg. Fahr., and melt at a temperature of 100 deg. Fahr. as deter- mined by the cube-ih-water method. The coal-tar pitch was put on until it had a uniform thickness of not less than T$ inch. Imme- diately upon the first coat, and while it was still melted, was laid 1-ply of felt, lapping at least 4 inches on all cross-joints, and at least 12 inches upon all longitudinal joints. The felt was at once covered with a uniform thickness of the coal-tar pitch, and upon that was laid a second ply of felt which was also covered by not less than y inch of coal-tar pitch. This membrane extended over the ends and down 4. Iron Bands MX 2 ( Staggered 30 C . to C . \ Cross-section through Manhole. \ Cross-section between Manholes. FIG. 119. Cross-section of Atlantic Avenue Subway, Brooklyn, New York. the sides, as shown in the cross-section. After the waterproofing had thoroughly hardened, a 1-inch layer of Portland cement mortar was laid uniformly over it with a trowel. This mortar coat was laid in 5-foot squares alternately for the purpose of providing for expan- sion and contraction. The work was accomplished without difficulty and with very good results. Manhattan-Bronx Rapid Transit Subway. The first Rapid Transit Subway in New York City built and finished between 1900- 1903, was waterproofed with a membrane composed of two to eight plies of felt, each mopped with hot asphalt, as laid. On several small sections of the subway, the felt waterproofing was made more 334 WATERPROOFING ENGINEERING effective by the application of one or two courses of hard-burnt brick laid in hot asphalt mastic. This was generally against the 2-ply membrane. The membranous waterproofing on the exterior surfaces of the masonry shell made it unnecessary to provide an extensive system of drains or sump pits of any magnitude, for the collection and removal of water from the interior of the subway. A few leaks have developed, mainly due to enlarged cracks, which required extensive repairs; but in general the waterproofing is good after twelve years' service. The Dual Subway System, New York City.* Two types of water- proofing were used on the 48 miles of new two-, three-, and four- track subways, viz., the bituminous membrane and the brick-in- mastic envelope (the latter, described under examples of mastic applications), the former on the roof between stations and on side walls at stations when above mean high or ground water; the latter both at and between stations on roof, side walls and floor when below mean high or ground water. See Table XXI for details. The fabric used for the membrane was 7J and 8 ounces open- mesh, jute burlap saturated and coated with bitumen. The application of the membrane to the roof is typical of its general use on the entire structure. The concrete roof was swept clean and all surface projections chipped away. The smooth sur- face, if dry, was then carefully mopped with coal-tar pitch, using ordinary wash mops for this purpose. The treated fabric was care- fully unrolled on the mopped surface (see Fig. 120) stretched across the entire width of the subway, where possible, overlapping 1J feet on either side. As it was unrolled it was pressed into the still hot coal-tar pitch and its surface mopped. A bond with the first coat of binder on the concrete surface was thus made through the open- mesh of the fabric. A second ply of fabric was then applied so that it broke joint either at the middle or at the one-third point of the width of the fabric. The surface of this layer was similarly mopped. A third strip of fabric was applied, breaking joint over the second and carefully pressed into the still hot binder. This process con- tinued until the required number of plies were laid. The surface of the top ply then received a final coating of binder, leaving it smooth. The waterproofing membrane that was thus formed was allowed to cool after which a 4-inch protective coat of concrete was placed thereon extending over the entire width of the subway. * Public Service Record, published by the Public Service Commission for the State of New York, First District, November, 1915, D. L. Turner, Chief Engineer. WATERPROOFING APPLIED 335 At the time of its application the pitch had a temperature of 325 deg. Fahr. in warm weather and 375 deg. Fahr. in cold weather. No waterproofing was done during an air temperature below 34 deg. Fahr. A few leaks developed during construction, but almost without exception proved to be due to careless workmanship, such as tares or punctures or foot-square holes accidently left unwaterproofed on the removal of struts and shores. FIG. 120. Showing Method of Applying Treated Fabric on Roof of Subway. (Note Rolls of Fabric, Pitch-carrying Pails, and Mop.) Bergen Hill Tunnels, Pennsylvania Railroad.* In waterproofing the Bergen Hill tunnels of the Pennsylvania Railroad System, three general types of construction for the arch were decided on, as shown in Fig. 121. The first, as shown at A, was to be used where the tunnel was quite dry. In this type the sand wall was omitted entirely and the concrete and rock packing were built up together, the rock packing impinging to a certain extent on the concrete and the concrete squeezing somewhat into the rock packing. The section shown at B was used where the tunnels were damp or where there were slight droppers, not forming a continuous stream. The back lagging of 1-inch boards, which was left in place provided a practically smooth outer surface on the concrete arch and allowed the concrete and rock packing to be built almost simultaneously. It was con- * Transactions of the American Society of Civil Engineers, Vol. 68, p ; 142. 336 WATERPROOFING ENGINEERING sidered that the free drainage through the rock packing, the surface of the boards and the smooth outer surface of the concrete in the arch would allow the comparatively small quantity of water in these parts of the tunnel to find its way to the sides, thence to the ditches at the bottom, rather than percolate through the concrete. This proved to be very generally the case, as is shown by the dry condition of the tunnel as built. The back lagging was used over the arch, Method of Method of making la PP in * Mats Three-ply MaU DETAILS OF WATERPROOFING One layer of felt with 4" overlap to be nailed to lagging of inch boards, using tin washers on nails over the whole of the intrados of the arch be- fore starting any concrete or placing any of the permanent felt and pitch waterproofing. The waterproofing over the arch can be laid in mats of three thicknesses of felt properly joined together with pitch made as shown diagrammatically at x. Each of these mats of three-ply felt will be overlapped half the width of the mat, as shown diagrammatically at y. FIG. 121. Various Types of Arch Waterproofing Used on Bergen Hill Tunnels. both where the sand wall was built and where it was omitted, as well as being placed over the waterproofing of the arch as an armor course where waterproofing was required. Where the sand walls were built and waterproofed, and where the waterproofing was not carried over the arch, the waterproofing was turned in at the top, as shown at C. The third method provided for waterproofing the whole of the arch. This was the same as B except for the addition of the water- proofing inside the back lagging. In placing this waterproofing, the felt was cut in strips about 11 feet long (about 1 foot longer than the length of a section of arch) and six thicknesses were cemented WATERPROOFING APPLIED 337 together with hot coal-tar pitch. These mats were then laid, shingle- fashion, as shown at D, up the sides of the arch until a space about 5 feet wide remained at the crown; shorter mats were then brought out over this, laying them perpendicular to the axis of the tunnel. Care was taken in making all laps, irrespective of the direction in which the arch was built, so that they would lay with the grade, that is, so that the water would tend to flow over the edges of the laps rather than against them. The method of waterproofing that part of the timbered section which was very wet is shown at F. A lagging of 1-inch boards was nailed up the sides sjid to the soffit of the segmental timbering, all the spaces outside of this lagging being carefully filled with rock packing. Before starting any concrete work a single thickness of waterproofing felt was nailed to the inner side of the lagging, which not only served to protect the finished surfaces of the concrete from the water which fell copiously from the roof, but also provided a comparatively dry surface to which the regular 6-ply waterproofing could be cemented with pitch and held in position while the concrete was placed against it Boston Tunnels.* A section of the Boston, Mass., subway con- sists of two tunnels underneath the Fort Point Channel. These tun- nels are built with an outer shell 9 inches thick made of Southern long-leaf pine-wood segments and an inside concrete shell 2 feet thick (minimum) with steel reinforcement. These tunnels are water- proofed by the application of a bituminous membrane to the interior of the wooden shell before placing the interior concrete lining (see Fig. 122). This membrane consists of layers of treated cotton fabric mopped with hot asphalt. Two layers are put on 'the invert and three on the sides and arch. In applying the waterproofing to the sides and arch, the first layer of cloth was mopped on one side with asphalt and then nailed to the wooden lining with roofing nails, the mopped side being against the wood. The second and third layers were then stuck on with successive moppings of hot asphalt. The result after three years' service is entirely satisfactory. Waterproofing Railroad Viaducts. The following unique method of waterproofing the Martins' Creek and Tunkhannock Viaducts on the new line which the Lackawanna Railroad has recently built west of Scranton, Penna., is described as follows by Mr. G. J. Ray, Chief Engineer. f "The structures referred to were treated alike, the same waterproofing materials being used in each case. The * Engineering Record, August 21, 1915. t Engineering News, Vol. 75. March 2, 1916. 338 WATERPROOFING ENGINEERING floor system over each main arch is divided into three parts by four transverse expansion joints two adjacent to each pier and one at each of the quarter points of the span. The floor is drained by downspouts through all spandrel walls, excepting those at the two intermediate expansion joints, and the drainage is discharged into the openings between the two ribs of the main arch. The drainage is prevented from flowing over the expansion joints by dikes built across the floor (enlarged details are shown in Fig. 123). " The waterproofing proper was done by using three plies of saturated cotton fabric laid in hot asphalt. The concrete was first FIG. 122. Waterproofing is Placed against Wooden Lining and Outside of Concrete on Shield-driven Tunnel, Boston, Mass. mopped with the hot asphalt. The three layers of cloth were then laid in the usual manner, each layer being mopped before the applica- tion of the succeeding layer. This waterproofing was carried up the sides of the parapet wall to the top of the ties and directly across all expansion joints, so that the waterproofing was in reality continu- ous from one end of the bridge to the other. At the expansion joints one additional layer of the saturated fabric was laid across and folded in the expansion joint beneath a copper flashing, similarly laid, over which the three layers of waterproofing were placed. A fold was provided in the waterproofing at the joints to provide for expansion and the entire joint filled with the hot asphalt. WATERPROOFING APPLIED 339 " As a protection to the waterproofing, asphalt-mastic mixed with washed torpedo gravel, was applied hot in two f-inch layers over the entire area of the waterproofing. In order to avoid injury to the waterproofing by the hot mastic, 1 ply of asbestos felt was first laid LONGITUDINAL SECTION OF VIADUCT SHOWING POSITION OF DIKE JOINTS OVER PIER 3-Ply Cloth 16-oz Copper "A" 1-Ply Cloth SECTION A-A SECTION B-B FIG. 123. Dike Form of Expansion Joint, and Details of Waterproofing on the Martin's Creek Viaduct. over the entire area of the membrane. An opening was left in the mastic directly over the center of each expansion joint and filled with the hot asphalt. The asphalt-mastic was used for protection in prefer- ence to brick or concrete, since our experience elsewhere with this mastic, under ballast, indicates that it does not crack and in reality 340 WATERPROOFING ENGINEERING forms a secondary waterproofing surface on which the drainage readily passes to the downspouts." Terrace, United States Capitol. The pavement over the terrace chambers of the United States Capitol at Washington, D. C., has been made watertight by the membrane system after many failures by other systems.* Many methods of waterproofing have been tried on this great expanse (about 200,000 square feet) of walk, to wit: felt and coal- tar pitch, asphalt and burlap, sheet asphalt, etc. In 1906 a sheet- lead pan was placed under one section. The sheet lead was bedded in cement mortar on the base slab and was covered with a 3-inch reinforced concrete slab and a 1-inch wearing surface. But even this construction was of no avail, partly because of the extreme expansion movement, partly because of unskilled burning of the sheet joints and partly because of the inherent difficulties of flashing around the vault light frames. The sheet lead on being uncovered was found to be considerably pitted. The expansion and contraction movements of the terrace struc- ture are excessive, owing to wide variations in temperature and extreme exposure.' Insufficient provision was made for inevitable expansion movement, and to this defect can be finally traced the repeated failures to keep the terrace chambers watertight. Final success was largely due to recognizing expansion difficulties and pro- viding for such movement by watertight, sealed expansion joints. Specifications were issued for this work in 1914. The notable features of these specifications consisted (1) in securing a bituminous compound having maximum adhesiveness and cohesion, (2) in using small (1 square yard) freshly saturated cotton fabric sheets, with wide laps, mopped into place and covered with protective masonry, (3) in the free use of special expansion and flashing joints. The material over the terraces was removed down to the con- crete slab over the floor arches which disclosed numerous fractures in the base slab. Each crack, treated as an expansion joint, was cleaned out, heated with a gasoline torch, partly filled with a special asphalt compound and tooled with a hot iron as shown in Fig. 124. The slab was also cut for expansion joints, as shown in Fig. 125. After the expansion joints were filled, the pavements were brought up to subgrade by a filling of 1 : 3 : 6 concrete. Upon the leveled subgrade was laid single sheets of impregnated cotton drill. The sheets were 1 yard square and were laid with 2-inch laps. A small area of subgrade was cleaned and mopped with hot compound just * Engineering News, Vol. 76, No. 14, October 5, 1916. WATERPROOFING APPLIED 341 previous to laying each sheet. The laps were made tight by follow- ing with a hot smoothing iron. Upon the membrane thus made there was laid, as armor for the waterproofing and as a wearing surface, a granolithic pavement (1:1:2 mixture with i to f inch washed bluestone chips), marked off in squares. These squares were sepa- rated by expansion joints continuous with the expansion joints in the subbase, as shown in Fig. 125, also along the balustrades, vault lights, and at every point where flashing would ordinarily have been employed. In waterproofing the expansion joints, the cut in the bottom slab was heated, painted and partly filled with the asphaltic compound. Then the membrane was brought down into the opening and the joint pointed with mortar. The joint was covered with a patch strip FIG. 124. Slab Cracks Made into Expansion Joints in Waterproofing the Capitol Terraces, Washington, D. C. (see detail X on Fig. 125), completing the lower half. When the granolithic paving was laid, wood strips, tapered f to J inch, were inserted as joint forms. When the concrete had set, the wood was pulled out, the opening heated and partly filled with the compound. The remaining space was pointed with mortar. In this way a covered and sealed reservoir was created at, each expansion joint. As the structure contracts and expands, the mortar plug is drawn down or forced out, the seal being preserved. After one summer's use the joints were found all closed nearly tight, demonstrating that by use of a thin plastic membrane underlying the wearing surface the latter could be kept from spalling or cracking. Manhattan and Brooklyn Railroad Viaducts. In building rail- road viaducts through city streets, where space is usually very valuable and scarce, and economy of operation the governing factor in the type of structure required, it has become the practice to con- struct the stations underneath the track level, instead of projecting 342 WATERPROOFING ENGINEERING WATERPROOFING APPLIED 343 them into the side streets on a level with the tracks. This new practice necessitates the portion of track floor or road bed directly over the station mezzanine to be perfectly watertight. To best accomplish this the steel work at these locations of the elevated No.18 Galranized wire lath 1^'mesh 1' 6" wide across brackets. ,. _ '. ':. ..-^..v...' ;/-.;-;:-v:-J-., . ... ..::-.-.....: .--. ^JU ..-.- :' T- N N6.18 Galvanized wire lath 1J m / f Waterproofing shall be flashed 3'0"wide, entire length. V < over brackets and against girders v to form a perfect seal. CROSS SECTION "A-B" Waterproofing ired PLAN SECTION AT BASE OF RAIL CROSS SECTION OF CONCRETE DECK ON THROUGH SPANS SHOWING METHOD OF WATERPROOFING A PLACING. OF PROTECTIVE CONCRETE METHOD USED BY NEW VORK MUNICIPAL RAILWAY CORP. ON BROADWAY ADDITIONAL TRACKS BROOKLYN, NEW YORK FIG. 126. Method of Waterproofing Concrete Decks on Through Spans, Used by the New York Municipal Railway Corporation. structure should be designed free of bays and unnecessary connections, and should also be encased in concrete. This concrete, forming the roadbed, may be constructed in sections as shown in Fig. 128, which is not advisable, or in monolithic form as shown in Figs. 126 344 WATERPROOFING ENGINEERING and 127. A design very successful in this respect is used by the New York Municipal Railway Corporation of Brooklyn, N. Y., on several of its elevated lines (see Fig. 126). Waterproofing on the concrete roadbeds over the mezzanine floors of these stations consists of a 2-ply membrane composed of treated cotton fabric and asphalt binder, applied over the concrete and lapped on to the steel girders. Sometimes the ends of the membrane were Surface of Concrete: At Stiffener Angles Between Stiffener Angles 4 Lap of Membrane Construction Joint Reinforcing Rods Stiffener Angle ISOMETRIC VIEW SHOWING DETAIL "A" OF CONCRETE AT STIFFENER ANGLE Waterproofing Membrane FIG. 127. Section of Girder of Railroad Viaduct Showing Membrane Water- proofing, Protective Concrete, and Drip Channel. put into V-joints between the concrete and steel webs; these joints were then filled with an adhesive, elastic, bituminous compound. Over this membrane was placed a minimum of 4 inches of protective concrete. This concrete is brought up the sides of the girders to the top flange in monolithic form. This trough-type construction of track floors has proved very succeesful. A design even more efficient than the above one, from the waterproofing standpoint, is shown in Fig. 127. In this design a dripping surface is provided by the WATERPROOFING APPLIED 345 substitution of a steel channel for one of the cover plates of the steel girder. Fig. 128 shows the design of a steel and concrete roadbed on a few railroad viaducts in New York City. The waterproofing details, one of which is shown in Fig. 129, were not entirely adequate. In connection with the design and construction of watertight steel and concrete road beds of railroad viaducts it is proper to point out to the engineer whose duty it is to design the waterproofing for such locations that he would do well to carefully study the details connected therewith. He knows, for instance, that the structure is subject to 3x2 Sleepers Platform 2 Board Waterproofing ^"Expansion Bolta 2"x 12 "Lumber a Rods 1 6 Ctrs. Mezzanine Floor , 3' Finish^ a Rods 6 Ctrs. y>"a Rods i 6' Ctrs. FIG. 128. Typical Construction , of Mezzanine Roof on Elevated Railroad Structures in New York City, Showing Location and Protection of Mem- brane Waterproofing. severe vibration; he should know, also, that a comparatively thin layer of concrete or mortar is almost useless for the protection of waterproofing under such conditions. He probably knows that only the membrane or perhaps the surface-coating types of waterproofing are serviceable for such a structure, but he should know also that joints between steel and concrete can remain watertight only so long as the joint filler remains plastic, though even this is doubtful, in view of the difficulties experienced in the design lastly referred to. Still another feature peculiar to such structures, as shown in Fig. 128, would be revealed by a careful study of details and that is, that 346 WATERPROOFING ENGINEERING openings, large and small, crevices and pockets in the joints and connections of the steel members which cannot be filled or covered with the bed concrete, require calking. Or else the waterproofing must be carried up the sides of the steel work, suitably protected and high enough to effectually prevent the percolation of water through the joints and connections. Unless either of these things is done no amount or quality of waterproofing of the roadbed proper will make the structure watertight. The following is a case in point that has been brought to the attention of the author and well illustrates the need for careful study of waterproofing details. Fig. 128 is a cross-section through a steel viaduct where a mezzanine floor, roadbed, and elevated plat- form are shown. The purpose of the concrete roadbed is to form a solid roof protection for the structure underneath, and the concrete of the ele- vated platform serves a like purpose. Now, it is rightly assumed by the engineer that the concrete may crack in the course of time and allow water to seep through to the mezzanine floor below. To obviate this danger he specifies a 3-ply membrane to be laid on the concrete, and covered with a 4-inch protective coat of concrete. Realizing that the protective concrete cannot make a watertight joint with the webs of the girders or beams, the concrete covering is designed so as to leave a V-shaped joint between it and the steel, as shown in Fig. 129. Even when a good elastic compound is used as a filler, the mate- rial cannot last for more than a few years and retain the properties requisite for waterproofing under this condition. Hence, sole reliance upon such a material to always effectively seal the joint, is unwar- ranted. Still more so is the use of a high melting-point bitumen, such as a hard coal-tar pitch or asphalt, because they become extremely brittle materials at temperatures but little below the ordinary. Al- most the first train that would cross the viaduct during cold weather would cause the pitch in the V-joints to crack and break away from one of the two surfaces, after which it would be useless as a means of preventing water from seeping through the joint or getting around and under the membrane. It is a fact that plastic joint fillers have actually failed in this regard; that is, the joints between the steel and the filler opened and nullified the value of the rest of the water- proofing. It is equally a fact that this result is inevitable, because of the varying rates of vibration between the structural materials when a train passes over the structure due to the relatively different inertia of the steel and the concrete. WATERPROOFING APPLIED 347 348 WATERPROOFING ENGINEERING An arrangement that would prove more efficient, though somewhat costlier, is shown at A in Fig. 130. In this form of construction, the effective waterproofing of the structure, or rather, the making of watertight joints is practically independent of the joint filler. This -3-Ply Membrane FLANGE ANGLE V- JOINTS 3-Ply Membrane Mop concrete ( under flashing FLASHING V-JOINT FIG. 130. Improved Types of V-joints for Elevated Structures. form of construction may also be modified so as to have the angle iron act as a flashing instead of a joint, as shown at B in Fig. 130. A strip of thin sheet lead between the angle and web is recommended. An arrangement, whereby the angle iron is eliminated and a copper flashing substituted, is shown at C, Fig. 130. This desien is WATERPROOFING APPLIED 349 efficient than the above two, because if the joint filler should fail to act, it would still be almost impossible for water to get around the flashing and seep through the joint. This design, however, is costlier and requires great care when applying and soldering together the sections of the flashing and in the selection of the metal. In design- ing the protective concrete, it is often necessary and always advis- able to reinforce it with some form of wire mesh of which the trans- verse ends should be left projecting somewhat into the joint filler. Fig. 131 shows a way to utilize the protective concrete so as to secure watertightness in the track floor. Other methods will undoubtedly mm. FIG. 131. Waterproofing Details around Ferrules at Drains, also Showing Increased Utility of Protective Concrete over Membrane on Mezzanine Track Floor of Elevated Structure. suggest themselves upon careful consideration of the conditions at hand. The purpose of this digression is merely to call attention to the need of studying waterproofing details and carefully selecting the materials. Perhaps the citation of another glaring instance of an ineffectual design and application of waterproofing will impress the architect, engineer and contractor with the serious consequences following a disregard of the need to study details and understand the selection of waterproofing materials. A very important station on one of the Brooklyn (New York) Elevated lines consists of a double-deck concrete structure built partly below ground surface. The ceiling above the platform of the lower deck is raised and forms the train platform of the upper 350 WATERPROOFING ENGINEERING deck. The track floors between the platforms of the upper deck are waterproofed with a 6-ply membrane made of treated jute fabric and coal-tar pitch having a melting-point of 120 deg. Fahr. by the cube-in- water method. This membrane terminates directly over the webs of the platform girders as shown at A, Fig. 132. These girders support concrete walls which, in turn, support the platform of the upper deck. The first summer after the station was com- pleted considerable quantities of the binder exuded through and all along the construction joints between this concrete and the top flange of these girders. u^=^ ^ ' 10' ft" ^-^aHJ Platform Upper Level T 1 . ' Protective concrete placed Jon waterproofing before track was placed FIG. 132. Cross-section of Station Platform and Track Floor, Showing Scheme of Waterproofing Proposed and Used on a Sub-level Railroad Structure in New York City. The resulting defacement of the structure and injury to the water- proofing was, however, not due to a poor grade of material nor bad workmanship in the application of the waterproofing, but was entirely due to faulty design, as is evident from the figure, and the neglect to specify a binder of an asphaltic nature or a coal-tar pitch of at least 30 deg. Fahr. higher melting-point. That this precaution should have been taken follows from the fact that the station has a super- structure which is exposed to the elements and hence the concrete may easily acquire a temperature above 100 deg. Fahr. in the sum- mer time. WATERPROOFING APPLIED 351 Another point worth mentioning is that the purpose of the water- proofing membrane in this particular structure is such as hardly requires more than three plies, and the way this should have been applied is shown at B, in Fig. 132, which is self-explanatory. Waterproofing Reinforced Concrete Standpipes. In the design of reinforced concrete standpipes, engineers have hitherto met with little success in obtaining watertight tanks for several reasons: 1. Because of insufficient attention to proper grading and proportioning of concrete aggregates. 2. Imperfect design of expansion joints (see Fig. 45 for a suc- cessful type of expansion joint). 3. Laxity in supervision and workmanship during construction. 4. Insufficient attention to details. Nearly all standpipes are so conditioned during their use that the concrete, especially the lower portion of the standpipe, is subjected to varying stresses consequent upon changing heads of water. During this action the stresses in the reinforcement likewise vary, hindering the silting up of minute cracks that may have formed and which after a freezing season may become dangerously large. Hence, it may be concluded that any structure subject to so many different kinds of stresses as is a concrete standpipe is best made waterproof by the application of a bituminous membrane of from two to four plies of fabric or cotton drill applied on the inside, and covered with a coat of mortar J to 1 inch thick. This method obviates the need of extraordinary precautions in grading and super- vision, and it will also be found that the cost is no greater and results more certain than when using either the integral or self-densified system of waterproofing. This method has been followed in several instances with success. Waterproofing Floor of Pneumatic Caisson. To aid the engineer in his judgment and to avoid delay in the execution of the waterproof- ing work in hand, he will do well to resort to some practical field tests for the determination of the working properties of a material or method not heretofore used or not used under extraordinary conditions. A case in point is the following: Specification require- ments for waterproofing the floor of a pneumatic caisson used in connection with the construction of two tunnels under the East River connecting the William and Clark Streets subway between the boroughs of Manhattan and Brooklyn (see Fig. Ill) called for a " soft pitch which will soften at 32 deg. Fahr. and melt at about 60 deg. Fahr. so that it can be spread without heating." Its use was intended for waterproofing under compressed air where the fumes 352 WATERPROOFING ENGINEERING of hot melted coal-tar pitch would be unbearable to the workmen and give rise to fire risks. But such a low melting-point coal-tar pitch is not a commonly used waterproofing material and must be made up specially, hence delay and increased cost may result. The compressed air chamber was under about 20 pounds pres- sure, and had an air temperature of about 75 deg. Fahr. After completion, the concrete floor and the waterproofing underneath would have a temperature about 20 deg. below this, with the result that the low melting-point pitch would exude from cracks or would tend to flow toward any hollow or other depression in the concrete and perhaps nullify the purpose of the waterproofing. To avoid this condition and still use coal-tar pitch, for pitch was the only material allowed under the specifications, a straight-run coal-tar pitch having a melting-point of about 120 deg. Fahr. by the cube- in-water method, was first tried; that is, it was heated to about 325 deg. Fahr. or over, poured in small buckets and lowered into the caisson. But coal-tar pitch, when heated to a temperature of about 325 deg. Fahr. as was done in this instance, fumes offensively. A test, by the author, to determine the temperature at which fumes commence to be given off by the molten pitch showed that hardly any was given off until a temperature of about 225 deg. Fahr. was reached. Hence all that was required was not to heat the coal- tar pitch beyond this point and a regular, stock material could be used. After a single trial it was used in this manner very success- fully. However, in the case of another caisson under about 40 pounds pressure per square inch, the soft grade of pitch called for in the speci- fication was used (necessitated by the greater fire risk) and the work well accomplished. Waterproofing Steel Swimming Tank.* A swimming tank, 30 by 60 feet in plan, and from 4 feet to 8J feet deep, situated between the 10th and llth floors of the Union League Club House in Chicago, was waterproofed by the application of a sheet-lead membrane and a felt membrane against the lead. Before applying the sheet-lead membrane the rivet heads on the inside of the girders forming the sides of the tank were flattened to J inch. Over the entire area 1J inches of cement mortar was put on with a cement gun. Upon this mortar coat the sheet lead, weighing 4 pounds per square foot (about Te inch thick), was placed and tacked to wooden strips set in the mortar. All the joints were soldered. Then the felt membrane was applied, being bonded with coal-tar pitch, and covered with 4 inches of cement mortar also put on with the cement gun. The entire * Engineering Record, Vol. 75, No. 3, January 20, 1917, p. 107. WATERPROOFING APPLIED 353 inside was then lined with ceramic tile J inch thick, set in cement mortar. The above scheme, suggested by the contractor, and which proved very satisfactory, was substituted for the original specifica- tion calling for membrane waterproofing with calking and welding of joints to make the steel watertight. EXAMPLES OF MASTIC APPLICATIONS Waterproofing Roadbed Over Mezzanine. Some of the track floors over the station mezzanines on an elevated railroad in Brooklyn, New York, consist of a framework of steel beams and girders with concrete slabs in the open spaces, forming a series of bays (similar to Figs. 128 and 129). These bays are waterproofed with a mastic sheet approximately 2 inches in thickness placed directly on the concrete. Each bay is drained by a pipe to the adjacent one until the water reaches an end but central bay, from which it passes into a copper gutter. The drains are 3-inch wrought-iron pipes, 12 inches long, passing through the steel webs to which they are fastened by means of ferrules and made to adhere to the mastic. Before the mastic was applied to the concrete slabs, 2-inch strips of the steel webs were mopped at the required elevation with asphalt to secure a good bond between both. The mastic consisted of approximately 12 per cent asphalt, 14 per cent sand, 22 per cent grit, and 52 per cent limestone dust. Though the mastic was well made and applied, and was in good condition more than a year after application, it gave very poor waterproofing results. This was directly traceable to the poor bond between the steel webs and the mastic, being broken by the severe vibration in the structure and especially the non-synchronous vibration between the concrete slabs and the steel framework. The Dual Subway of New York City. In waterproofing the new subways in New York City two systems were used. The membrane (described under examples of membrane applications) and the brick-in-mastic envelope (described below). The latter method was used in the manner noted in detail, in Table XXI and illustrated in Fig. 1324. The floor and side walls of the subway below ground or mean high water, when passing through earth, also the roof of stations, were waterproofed by the brick-in-mastic system. This consisted of one or two courses of ordinary building brick embedded in mastic. The mastic was composed of a minimum of one-third asphalt and 354 WATERPROOFING ENGINEERING two-thirds sand and cement, or sand and limestone dust. It was mixed hot on the work in round-bottom iron kettles of 50- and 100- gallon capacities (see Fig. 77) at a temperature not exceeding 375 deg. Fahr. IPlvWP One or more "Layers of 4 Concrete 2 Layers of Brick in Asphalt i ply W P '_ ', ' / Brick in A&phalt .;/ | | V / / !_, ' j 2 Min. 2"Min 3 Ply W. P. i 4 Concrete AT STATIONS 4 Concrete 2 Layers of Brick in Asphalt j p\ y w.P. Concrete 6 Concrete - 3 Concrete BETWEEN STATIONS FIG. 132 A. In applying the brick-in-mastic to the floor of the subway, the surface of the concrete bed, which was generally from 4 to 6 inches thick, was covered with a single ply of waterproofing felt or fabric, and its surface completely mopped. This served as a dry ply upon which to place the brick-in-mastic envelope. WATERPROOFING APPLIED 355 Two courses of brick-in-mastic were applied to the floor and together had a minimum depth of 5 inches. The thickness of the various brick-coverings of mastic was not less than f of an inch (see Fig. 133). On side-wall construction, the vertical surface of the excavation was first carefully faced with concrete. Forms were placed 8 inches FIG. 133. Showing Application of First and Second Layers of Brick-in-Mastic and Method of Sliding Bricks into Place. (Note Mastic Covering Finished Portion between the Two Posts.) from this facing and the brick and mastic laid therein, as follows. A quantity of mastic was poured into the space and bricks laid in it on their largest bed and in a double row, leaving a minimum of f-inch joints around all faces. After cooling, the forms were removed and the main concrete wall of the subway was built against the mastic wall. No leaks developed where the brick-in-mastic envelope was used. 356 WATERPROOFING ENGINEERING EXAMPLES OF INTEGRAL WATERPROOFING APPLICATIONS Waterproofing Reinforced Concrete Reservoir.* In renovating a 1,000,000-gallon reinforced concrete reservoir at New Ulm, Minn., watertightness was secured in the structure by exercising special care during construction to grade the concrete aggregate. Pebbles, varying in size from J to 2J inches screened from a gravel bank, were used in the floor and walls, as experiments had shown that these pebbles made a denser concrete than broken stone. To reduce the permeability of the concrete to a minimum, however, 20 pounds of hydrated lime was used to every barrel of cement. After the forms were removed, the walls were brushed and cleaned with steel brushes, and two coats of 1 : 2 cement mortar, about | inch thick, water- proofed by the addition of 10 per cent of finely powdered iron, were applied. The floor was treated with a slush coat of 1 : 2 mortar which after setting received a brush coating of waterproofed mortar. After water was let in some leaking took place and cracks developed which were finally remedied and the reservoir was rendered watertight. Concrete Tank at Duxbury, Mass. A reinforced concrete tank in Duxbury, Mass., f 40 feet inside diameter and 35 feet high was made watertight by using a rich* concrete with an addition of hydrated lime. The bottom is a reinforced concrete slab built in two 12-inch layers, the lower one of 1:2:4 concrete and the upper one of 1 : 1J : 3 mixture with the addition of 5 per cent hydrated lime. The walls are of 1 : 1 : 2 concrete with 5 per cent of cement replaced with hydrated lime, and the dome is of 1 : 2 : 4 concrete. In order to prevent water from passing through the joints made by each day's work, thin steel bands 4 inches in width were inserted so that one- half of the width was embedded in the old work and one-half in the new. EXAMPLES OF SELF-DENSIFIED CONCRETE APPLICATIONS Reinforced Concrete Filter Plant. In the construction of the filter plant at Lancaster, Pa., in 1905, a pure-water basin and several circular tanks were constructed of reinforced concrete. The pure- water basin is 100 feet wide by 200 feet long and 14 feet deep, with buttresses spaced 12 feet 6 inches center to center. The walls at the bottom are 15 inches thick, and 12 inches thick at the top. Four circular tanks are 50 feet in diameter and 10 feet high, and eight * Engineering Record, December 17, 1910, Vol. 62, No. 25. t Engineering News, Vol. 75, May 6, 1916. WATERPROOFING APPLIED 357 tanks are 10 feet in diameter and 10 feet high. The walls are 10 inches thick at the bottom and 6 inches at the top. A wet mixture of 1 part cement, 3 parts sand, and 5 parts stone was used. No waterproofing material was used in the construction of the tanks, and when tested, two of them were found to be watertight, the other two had a few leaks where wires, which had been used to hold the forms together, had pulled out when the forms were taken down. These holes were stopped up and no further trouble was experienced. In constructing the floor of the pure-water basin a thin layer of asphalt was used, but no waterproofing material was used in the walls, and both were found to be watertight. Reinforced Concrete Watertank. A reinforced concrete water- tank, 10 feet inside diameter and 43 feet high, designed and con- structed by W. B. Fuller at Little Falls, N. J., has some remarkable construction features. It is 15 inches thick at the bottom and 10 inches thick at the top. The tank was built in eight hours, and is a perfect monolith, all concrete being dropped from the top, or 43 feet at the beginning of the work. The concrete was mixed very wet, the mixture being 1 part cement, 3 parts sand, and 7 parts broken stone. No plastering or waterproofing of any kind was used, but the tank was found to be absolutely watertight. The large aggregate was, however, scientifically graded. EXAMPLES OF GROUTING APPLICATIONS Waterproofing Pressure Tunnels. Some of the tunnels of the Catskill Aqueduct of New York City * were made watertight by grouting behind the tunnel lining. This grouting followed the con- creting within a period of two to three months, when the concrete had attained sufficient strength to resist high grouting pressures. Air-stirring, grouting machines of the Canniff type, holding about 25 gallons, were generally employed for this work, though a few mechanically stirred Cockburn machines of the same capacity were tried. For low-pressure work, by which the voids about the lining were filled, air direct from the compressor plants was used; for the high-pressure work the air pressure was raised by means of auxiliary high-pressure air compressors. For filling the voids in the dry packing and the cavities and shrinkage spaces left over the arch concrete, the grout was mixed in the proportion of one cement to one sand, with an equal volume of water, and forced in under pressure of 80 to 100 pounds or more * Engineering News, Vol. 73, February 4, 1915. 358 WATERPROOFING ENGINEERING per square inch, depending on the ground-water head. Neat cement was employed in filling the drip pans and other thin cavities. See Fig. 134 for details. No masonry cutoff walls were built to stop the grout, except where dry packing was to be filled, and no attempt was then made to make them tight at the crown of the arch. Work was started at some favorable point where the grout would of itself make a cutoff and carried steadily on, connecting to each pipe in turn. The general practice was to commence grouting through the pipes nearest the invert, and upward to the arch. On completion of the low-pressure grouting, neat-cement grout, generally mixed in the proportion of four to eight volumes of water to one of cement, though sometimes containing as much as fifteen volumes of water to one of cement, was forced into many of the pipes previously grouted and into the deep-seated pipes, under pressures of 250 to 3'00 pounds per square inch, to fill the small spaces and seams in the rock about the lining. The cost of grouting the tunnels to watertightness ran from $2.50 to $3 per lineal foot of tunnel, including the costs for plant, materials and labor. The tunnel was made remarkably watertight as a result of these operations. Ashokan Dam CutofL* In making watertight the cutoff wall for the Ashokan Dam on the Catskill Aqueduct, a row of 3-inch grouting holes were drilled 20 feet below the bottom of the trench, reaching the greatest depth at which the boring tests had indicated the presence of seams. Similar grouting holes were drilled to about the depth of the cutoff to insure the sealing of any seams that might exist in the rock under the main body of the dam. Two-inch iron pipes were cemented in the tops of the drill holes and carried up into the masonry to permit grouting when the dam had reached sufficient height to withstand the pressure of the grout. These grout pipes were then grouted with neat-cement by the use of a Cockburn Bar- row grout machine of 4 cubic feet capacity, operated under a pres- sure of 25 to 80 pounds. The results were entirely satisfactory. Rondout Pressure Tunnel. In constructing the Rondout Pres- sure Tunnel of the Catskill Aqueduct, several wide shafts were sunk. These shafts had to be waterproofed to facilitate operations; espe- cially one shaft in which the seams were large and many. Twenty- seven vertical holes were drilled, 14 to 20 feet deep and capped with pipes and valves for the purpose of grouting these seams. A battery of 4 Canniff tank-grouting machines were set up at the top with 2^ -inch pipe in the shaft and a 2-inch hose connection at the bottom. At first the grout leaked back into the shaft in considerable volume. * " Catskill Water Supply of New York City," by Lazarus White, C. E. WATERPROOFING APPLIED 359 360 WATERPROOFING ENGINEERING Various methods were then tried to prevent this leakage the use of oats, bran, and ground horse manure, the latter finally clogging the seams and stopping most of the leakage in the shaft. The shallower holes took 2900 bags of cement and the 20-foot holes only 60 bags. This grouting proved to be so successful that it was deter- mined to grout some of the deeper seams known to be porous and water-bearing. EXAMPLES OF SPECIAL WATERPROOFING APPLICATIONS Harlem River Tunnels. The use of cast-iron, cast-steel, and iron and steel plates for waterproofing is not common but none the less quite practicable. Fig. 135 shows half-sections through the steel lining used as waterproofing for the Harlem River Tunnel tubes connecting the Lexington Avenue subway between Manhattan and Bronx boroughs, forming a part of the Dual Subway System in New York City. The steel (Fig. 135^4.) was sunk in a prepared channel in the river bed and surrounded with concrete within and without. This created an excellent watertight tunnel.* The same is quite true of the cast-iron and cast-steel tunnel linings used on the Pennsylvania railroad tunnels under the Hudson River and the New York Subway tunnels under the East River. See Fig. 136 for details of the type of cast-steel tunnel segments used on the two latter structures. These segmental linings make an effective waterproofing, though the joints are not absolutely watertight. The leakage, however, is insignificant, as proven by the following fact. In the above- named tunnels, a sump of some form is provided at the lowest point of each tunnel or pair of tunnels and pumped out when necessary by pumps regularly installed. This showed that the daily leakage into the 5J miles of river tunnels of the Pennsylvania Railroad is 2300 gallons. The magnitude of this may be better appreciated by stating that the entire amount of leakage for one day would be removed in one or two minutes by a pump of the capacity ordinarily used by contractors for foundations.! Rubber Sheet used on Waterworks Reservoir, t A reservoir built in Bellaire, Ohio, in 1905, was put into successful operation * See paper by Howard B. Gates, " Harlem River Crossing of the Lexington Avenue Subway." The Municipal Engineers Society's Journal, Vol. 1, No. 6, New York City, December, 1915. t Alfred Noble, in Journal of the Franklin Institute, Vol 175, p. 383. t Engineering Record, June 3, 1916. WATERPROOFING APPLIED 361 HALF SECTION- AT DIAPHRAGM SHOWING STEEL DETAILS Symmetrical about this line HALF SECTION BETWEEN DIAPHRAGMS SHOWING CONCRETE DETAILS FIG. 135. Harlem River Tunnel Tubes, as Built. 362 WATERPROOFING ENGINEERING for the first time in eleven years after its construction. This was made possible only after it was waterproofed by a unique method. Unstable foundations had caused cracks, particularly in one corner of the reservoir, which defied all the many attempts to make the structure watertight until the following inexpensive method was used. A strip of sheet rubber, stretching 30 feet long by 3 feet wide by | inch thick, was placed in the corner of the basin covering the crack. A box, built around this rubber-covering and filled with soft mud, kept the sheet in place. Another large crack, in the bottom of the FIG. 135A. Steel Tubes for Harlem River Tunnel, Lexington Avenue Subway, before Sinking. basin, was also covered with a strip of rubber and held in place by a cement mortar covering. The basin was then filled with water, and it was found that, although the crack in the wall opened YQ mcn still further, there was no leakage. This method was suggested and carried into effect by Mr. F. J. Lewis, a resident of Bellaire. Timber Sheeting Waterproofing for Subaqueous Tunnels.* Referring to Fig. 137, in which timber sheeting constitutes the waterproofing for a subaqueous tunnel, the author believes that if the form of tunnel construction indicated is at all practicable, the * Proceedings of the American Society of Civil Engineers for November, 1914. WATERPROOFING APPLIED 363 a| IS i 8 y /*^ t f 3 * 1 & a ^ jBuri..ff..d^ 1 (2,2 W L .= ! 1 i M o IEW BROKEN 6 * ~> < e JJJtLC-fL Sz = 3 pvff| Jog ^ c 'of ~ > co| < N^ o ! s ^ \ a M ! 364 WATERPROOFING ENGINEERING 1 Q WATERPROOFING APPLIED 365 proposed waterproofing method seems impracticable. To build a subaqueous tunnel and to waterproof it with creosoted, tongued and grooved yellow pine planking, pinned on the outside of the struc- tural material is a unique conception, though never attempted, to the author's knowledge. This form of waterproofing and its applica- tion, Mr. D. D. McBean, the originator, believes will be possible by the use of his patented " Subaqueous Working Chamber " for con- structing the tunnel. Basement Waterproofed with Sheet Lead Lining. The excava- tion for the basement of the Proctor & Gamble Mfg. Co.'s building on Staten Island, N. Y., was made in red clay. Due to the existence of swampy ground on the site, considerable seepage had to be contended against and prevented from percolating into the cellar. The floor and walls were built of concrete, and were waterproofed by the application on the inside of 1-ply sheet lead weighing 3 pounds per square foot. This sheet lead was also applied to the columns, the strips being carefully soldered together so as to make a seamless pan of the whole. On the floor the sheet lead was laid on a 1-inch sand cushion, and on the wall, directly against the concrete. The entire lead membrane was then protected with a 5-inch layer of concrete. The results obtained by this method of waterproofing were quite satisfactory. Cement-clay Cover for Hudson and Manhattan Railroad Tunnel. A waterproofing method, in which an impervious layer of cement and clay was interposed between water-bearing ground and a concrete substructure, was used in the recent addition to the Pavonia Avenue station of the Hudson and Manhattan Railroad in Jersey City, N. J. The work consisted in excavating, by tunneling methods and sub- sequently lining with concrete, a station opening in a water-bearing stratum 200 feet from the Hudson River bulkhead line and 50 feet below mean sea lavel. It was imperative that the concrete lining be watertight, but it had been the experience of the engineers in building the original tunnel that it was impossible in working under air pressure to use any applied waterproofing mats on account of the danger to workmen from fumes; expected expansion and contrac- tion with consequent cracks forbade the use of any integral water- proofing material. It had been noted that all of the river tunnels which rest in river clay were quite watertight, and it was believed that if a com- plete coating of clay could be obtained exterior to the tunnel lining, no more nearly perfect or complete waterproofing could be secured. The difficulty with any clay application was that when wet and soft 366 WATERPROOFING ENGINEERING the clay would change its form by squeezing. Therefore, experi- ments were made' with clay mixed with sufficient Portland cement to hold its form when set. Hudson River silt, which is a finely pulverized clay with a con- siderably larger proportion of silica than ordinary clay, was dried and mixed with equal proportions of Portland cement, applied through the medium of a cement gun as a heavy coating on every portion of exposed timbering and lagging in the tunnel. This produced a layer of impervious plaster about 2 inches thick against which the con- crete lining of the tunnel was placed. The method has proved suc- cessful, the station structure being practically dry under an extreme head of salt water. Iron-lined Coal Pits.* In constructing concrete coal pits for railway coaling stations of the elevator type it is essential that the pit (for the elevator bucket) should be watertight. The pit is usually considerably below the ground-water level and is subject to pressure, and when once put in operation it is a matter of difficulty and expense to get at it and make repairs. A plan, which has been used with success, is to place within the concrete a steel boot or tank with joints soldered in the field. A 6-inch thickness of concrete is placed first, and then the steel boot is set in position and the sections soldered. When this has beon made watertight it is lined with 6 inches of concrete. All attach- ments, bolts ladders, etc., are set in this inner lining. Fig. 138 shows such a pit having a boot 6 feet 11 inches by 11 feet 6 inches and a height of 11 feet, its top being above ground- water level. It is made of No. 20 galvanized iron, and the expecta- tion is that if the metal should rust in course of time it would still form a waterproof diaphragm by combination with the cement. The concrete is a 1 : 5 mix, made with gravel, and mixed moderately wet. The use of a similar boot composed of burlap and asphaltic composition has given fair success. To place a waterproof lining outside of the concrete would involve greater excavation and addi- tional form work. Calking Tunnels of Pennsylvania Railroad, f In making water- tight the East River Tunnels of the Pennsylvania Railroad, the joints between the cast-steel segments composing the tunnel rings were at first calked with a mixture of iron filings and salammoniac in the proportions by weight of 400 to 1. The calking was done by hand. * Engineering News, Vol. 76, October 5, 1916. t " The Subways and Tunnels of New York," by G. H. Gilbert, L. I. Wight- man and W. L. Saunders, WATERPROOFING APPLIED 367 Later, lead wool, calked cold by pneumatic hammers, was substituted with better results. This calking preceded the placing of a concrete lining about 1 foot thick inside the iron rings. One-to-one grout was then forced between the top of this inner concrete lining and the outer iron segments. Great care was exercised in this work and very good results were obtained. Waterproofing of the North River Tunnels of the Pennsylvania Railroad consisted in forming a rust joint (with a mixture of sal- Coal Car Track FIG. 138. Concrete Coal Pit Waterproofed with Sheet Steel Boot. ammoniac and iron borings) between the plates of the metal lining forming the tubes, and in taking out each bolt and placing around the shank under the washer at each end a grommet made of yarn soaked in red lead. Before calking with the rust mixture the joints were cleaned. The usual mixture for the joints was 2 pounds of salammoniac, 1 pound of sulphur and 250 pounds of iron filings or borings. Air hammers were used with advantage in calking this mixture into the joints. The results were variable and not always satisfactory. CHAPTER XI COST DATA ON MATERIALS, IMPLEMENTS, AND LABOR PLANNING AND ESTIMATING Importance of Accurate Estimates. Record costs do not always agree with the estimates given for any particular work because anal- ysis for systematizing labor operations preceding the making of such estimates are too often insufficient, or neglected altogether. This is illustrated by the enormous variations in bids received from contrac- tors for the same job. For example, the bids received for waterproof- ing a section of the New York Dual Subway in 1915 were as follows: A. B. C. D. ' E.' F. Maximum Difference (Per cent). Fabric membrane, 1-ply $0.50 liOO 2.00 25.00 7.00 $0.40 1.20 1.60 20.00 6.50 $0.45 1.80 2.40 18.00 7.50 $0.35 .75 1.40 22.00 6.00 $0.30 .90 1.50 20.00 8.00 $0.41 1.10 1.83 16.00 7.25 66 140 71 56 33 Fabric membrane, 3-ply Fabric membrane, 6-ply Brick-in-mastic, cu. yd Protective concrete, cu. yd On another section of the same subway, the following bids for waterproofing work were received: A. B. C. D. E. Maximum Difference (Percent). Fabric membrane, 1-ply $0.30 .70 1.30 25.00 10.00 $0.35 1.20 1.50 29.00 7.50 $0.40 1.10 1.40 20.00 9.00 $0.50 .90 2.00 18.00 8.50 $0.6C .80 2.25 8.00 100 71 73 61 33 Fabric membrane 3-ply Fabric membrane 6-ply Brick-in-mastic cu yd Protective concrete, cu. yd : . . To account for such marked differences in estimate figures several items enter into consideration; usually and mainly, these are the result of a wrong estimate of labor cost. The methods of manage- ment undoubtedly affect the cost to a very large extent, but this hardly explains the difference of 100 and 140 per cent in the esti- mated costs submitted by the different contractors. The variations 368 COST DATA ON MATERIALS, IMPLEMENTS, AND LABOR 369 are more probably due to the following four causes: (1) Inaccurate estimate of volumes or cost of materials; (2) inaccurate estimates of overhead costs and profits; (3) manipulation of estimate prices; (4) inaccurate estimates of labor costs. Material costs usually are figured without difficulty, and these, except during abnormal busi- ness conditions, are reasonably constant. Hence, only mistakes are chargeable here. The variation in overhead charges by two different estimators may be large because many contractors do not properly charge or divide their overhead items, but this difference on any one job cannot account for more than 15 or 20 per cent. Manipulation of estimate prices, that is, figuring high on one item and low on an- other, unless done with great skill and foresight, proves a profitless process so often that it is not generally resorted to. This would, however, in some cases, account for about 50 per cent of the varia- tion. Obviously, then, the big variations must be in the estimated labor cost. And this indeed is the item on which money is usually made or lost in contracting. Accurate Estimates Dependent on Accurate Methods. Accurate estimates by architects, engineers, and contractors should be made a matter of careful study. An appreciable saving would always result in the substitution of accurate methods for guesswork in esti- mating., Mr. Sanford E. Thompson, Consulting Engineer,* makes the following remarks in regard to the reduction of general construc- tion costs, which are also applicable to waterproofing costs. " Accurate cost keeping is of value in following up construction costs from day to day, in showing up waste labor and in providing a mark for the attainment of superintendents and foremen. Unless cost knowledge is in the form of small units, such comparisons cannot be made satisfactorily. '' To get the full benefit of a knowledge of unit costs, and in fact for this the knowledge must be even more thorough and include the unit times of performing the various operations, it must be utilized in the planning of the work in advance and in distributing materials and jobs; in selecting materials and methods which will result in lower labor costs; in adapting the construction plant to the special conditions; and, carried to its ultimate end, in laying out jobs for the workmen and giving them a reward for accomplishment. " Such management as this involves the adoption of factory methods in construction. Already the need of this is being recog- nized, but only to a limited degree. "Full economy in construction, however, will only be attained * Engineering and Contracting, March 1, 1916, p. 221. 370 WATERPROOFING ENGINEERING as the builder discards the haphazard rule-of -thumb method and con- siders his job with a view to thorough analysis, planning functional methods, and a complete study of details. By such methods as these will the labor of construction be brought to a more scientific basis and more nearly on a par with the material end of the work." LABOR AND MATERIALS Waterproofing Labor, Contracters and Manufacturers Graded. Among waterproofing concerns there are to be found the following classes: (1) Waterproofing manufacturers who manufacture and assume responsibility for the quality and effectiveness of the water- proofing material; (2) Manufacturing waterproof ers who manu- facture and apply the waterproofing material under a guarantee; (3) waterproofing contractors who buy the waterproofing material ready made, supply the labor, and supervise and guarantee the work; (4) waterproofing subcontractors who often are furnished with the waterproofing materials, but always supply the labor, and give personal supervision to the work. Some of the concerns included under the above classes are not sufficiently responsible or experienced, hence it is often advisable to employ an experienced waterproofing inspector on the work, espe- cially when the magnitude of the work warrants the expense. Where this is not the case, experience has proven the advisability of con- tracting for the waterproofing work with a reputable and highly responsible waterproofing concern but always under a very specific guarantee. Many waterproofing concerns maintain laboratories and staffs of engineers who co-operate with the contractor, or builder, in deter- mining the proper system and materials for waterproofing a particu- lar structure. The service is often given gratis. In consequence, the advice, or information, is not always impartial, and it seems advisable that the buyer, builder, architect, or engineer, should investigate somewhat for himself. The result may not only be an improved design but often a reduction in the cost of waterproofing the structure. The labor employed on waterproofing work is also divided into several classes, as follows: (1) Foremen, who are men generally of large experience in waterproofing work; (2) Waterproof ers, men who do the actual waterproofing work, such as laying the brick and mastic courses, sheet mastic, or applying bituminous membranes; (3) helpers, men who help the waterproofers and incidentally learn the trade; (4) Kettlemen, men who tend the kettles in which the bitumen is heated or the mastic is made up; (5) laborers, men who COST DATA ON MATERIALS, IMPLEMENTS, AND LABOR 371 carry the bricks, wood, etc., to the waterproof ers and kettlemen, and perform all the unskilled labor required; (6) roofers, men who mainly waterproof roofs of buildings; (7) roofers' helpers, men who assist the roofers. In none of these divisions is any extraordinary skill required. Indeed, in the application of all waterproofing care and judgment are mostly required. It is not necessary to employ men of a particular trade to do water- proofing of a particular kind, but it is very essential to employ men with some experience in the particular branch of waterproofing. For example, in waterproofing a structure by the application of a brick-in-mastic envelope, it is not necessary to employ a bricklayer for this purpose, because no special bond of brick, nor refinement of line is required, as in building construction; but experience in hand- ling mastic and properly laying up mastic courses is necessary for good results. This, however, can often be done by the average waterproof er after a short apprenticeship. Besides, the difference in wages between bricklayers and waterproofers would materially affect the contract price of a particular waterproofing job. The general cost of waterproofing labor depends to a certain extent upon the locality of the work, the nationality of the workmen, but more particularly, of course, upon the character of the work performed. COST DATA TABLES The cost of most standard waterproofing materials, like other building materials, fluctuates with the market. The cost of patented or special waterproofing materials depends generally on the quantity bought. In buying waterproofing materials, it should be the aim of those responsible, to buy materials that are either well-known or of proven efficiency because in the end they prove to be the cheapest. Some concerns make a practice of renaming standard materials and selling them at vastly inflated prices. It is no simple matter to guard against this, but when large quantities of waterproofing materials are to be bought, it will pay those concerned to look into the standard materials on the market before buying any special ones. This has particular reference to materials used in the surface coating and integral systems of waterproofing, and joint-filling compounds. In the following tables will be found the cost of waterproofing materials, labor, and implements for the year 1914. These tables are compiled with more than approximate exactness. Certain other information is included which will be found helpful in estimating and ordering materials. For the duration of the present (1918) 372 WATERPROOFING ENGINEERING abnormal status of commerce, the cost and price figures given in the tables should be doubled. Table XXII gives the average wages, during 1914, of the differ- ent classes of workers employed in the waterproofing industry and their range includes eastern and western standards of wages. The lower figures usually represent the western scale. Table XXIII gives the cost and weight of waterproofing imple- ments and tools and some of the manufacturers who specialize in these. The variation and range in cost of each article is mainly due to the difference in size of the articles. Table XXIV gives the selling price at New York and weight of the most important and most extensively used waterproofing materials. The variation in prices is due to the fact that they in- clude the cost of handling, trucking, etc., except the freight rate, which is too variable. Table XXV shows the cost of different types of waterproofing applied. The profit to the waterproof er and roofer included in most of these figures ranges between 15 and 30 per cent. Table XXVI, " Cost of Tin for Flat and Standing Seam Roofing," enables the architect and roofer to calculate the cost of the roofing material from the cheapest to the dearest made tin plate. These prices depend on whether the base plate is iron or steel, and upon the thickness of the coating thereon. The coating consists of an alloy of tin and lead, and the weight of this coating, per box of 112 sheets, is the governing factor in the cost. This weight varies from 8 to 40 pounds. Those plates carrying less than 20 pounds are re- garded as the cheaper grade, while those carrying more are in the dearer grade. The weight of coating should be distinctly called for in any tin roofing specification, and also stamped on the tin sheets by the manufacturer. TABLE XXII. COST OF WATERPROOFING LABOR (!N 1914) ' Class. Wage Per Eight-hour Day. Remarks. Inspector. $4 00 to 5 00 Municipal and priVate inspection Foreman 4 25 to 5 00 Waterproof ers 3 . 50 to 4 . 50 On construction work of New York Kettlemen 2 . 00 to 2 . 50 Rapid Transit Subways. Union Waterproofers' helpers . . '. Laborers 1.75 to 2. 25 1 50 to 2.00 Labor. Unskilled labor. Roofers 3 50 to 4 . 50 Roofers' helpers 2. 25 to 2. 50 COST DATA ON MATERIALS, IMPLEMENTS, AND LABOR 373 a o 8 3 o-3 85. 5" S 2 S .13 I * &&-9 c3 c3 03 C C C O O O 'S'S'o r-C-OTJ c c c 322 cu^ . M-Qja^^ . t i-M " ' ca a "a? if! I 0) a) D *ra .3.2.2 a 1111 C (3 C 'B'S'H a s's's- & S 'o'o'o g o o o -S ^ h t- m rtdo P33*J +j-|J*J^ -(j+j-^ 222^ O>OO>O> o>O>^ OOOM isii s 374 WATERPROOFING ENGINEERING 2 giS a j>> 1 A SI cc g 3 .2 .* T3 P ,; ?(21 "g o| : JH sill I 5 " -2 2 d n .2 S^ o 3 > o o o 3 ^ 88 ^ a 2 S fe s. ii 8lO IO C Pll ^ * d ^ eT o o -4J 0> JH < s U a ^ ^ S P S o ^ a; r2 *o o ll-sl ^s O 03 If 5 - OQ cc - 1 j^ . 9 S 5 _ft 11 ^ &0^l342 42 S S CO 10 ^ ^. CQ O i-H O JL , ? i-H IO 1-1 O O5 O |> i i rJH O O i i i I CO OI-H loiocoi Oi o oo I-H co OOO COi-iCOOOO I-H (M PH IO ral m OI-H ^-10 g g g 8,8,8, 42 42 43 pQ 42 00 CO O 00 O*OO cOOOOt^iO rt^ T^O-* coot > -o t>. i i o a 8 4. o 1 8,1 42 42 OC Fabric (oil-tar Oil-tar pitch Paraffin (solid) Paraffin oil Cement (Portland >I2 ""cj a a a PQ PQ p wd Sa 's 376 WATERPROOFING ENGINEERING B Id 2O fc a " -C 03 ill I 1 G C > w v^CCt^OO^,,,!/^ S 1 O o3a rf*1 l S3 M^-^M^-^Sl^-t S^oS^oS^O g 02U CU C?U O > l-s 3 O "O T5 -*i "O "O T3 >> >>>>>> > 00 W g X CQ CQ a; 5 C J3 S3 CL( PH PH PH PH - i's I! -| W '5|''S,^ ^r-^ E I 1 2! G -j ^ a >> -ti TI 03 83 ^_. S? G g fi G ^ CO F -I!Ol I 8 ' s l- 5 ^ liu 'I S 15 ?3 d "^ G 5 ^ ^5 03 03 .+j 03 g g 8 teri lo i 1 -2 -S js ^ S 2 . i a> lfl - SS a te p p, te e d pitch b 3|i Is PQ ^.S S r 2 morta m and s iiil 531 fl5*a ,. 3 s ^^^5 sg !l c- S- 2 ^ 5*8 ii cS S-^ ^ 5 "ft Ajj T3 -f -2-3 " G c3 ^^3 .5^ 5 ft 3 h -03 li gg gg H H il -2 P- .S .S.S .S S S 00 03&Q CQ 1 I 11 H 2^ ?-5 Oi I 1 .-2 8 o C o o -3 o - - UO J>2 COST DATA ON MATERIALS, IMPLEMENTS, AND LABOR 377 g n o c'cy Materials Employed |o |o I |o | . "S lH^ldl |U lllflllll* "JJI'* *"S< P P Ps ^l^&l.g^&lsi filfilli' ufMi llMH !11I1^1' itBOgccO^SS^Oa" ^'moSg'SoJg'M O ^ l board sheathing under erage conditions. D 1 C3 1 3 48 "S 4, i i 51 ii o o "5*a a ~ 1 nj i li 41 1* li Is 378 WATERPROOFING ENGINEERING TABLE XXVI. COST OF TIN FOR FLAT AND STANDING SEAM ROOFING * TIN PLATES 14 BY 20. TIN PLATES 20 BY 28. When Tin Costs (per Box.) Flat Seam (Cost per Square). Standing Seam (Cost per Square). When Tin Costs (per Box). Flat Seam (Cost per Square). Standing Seam (Cost per Square). $3.00 $1.67 $1.85 $6.00 $1.57 $1.69 4.00 2.22 2.47 8.00 2.10 2.25 5.00 2.78 3.09 10.00 2.62 2.81 6.00 3.34 3.71 12.00 3.15 3.37 7.00 3.89 4.32 14.00 3.67 3.94 8.00 4.45 4.94 16.00 4.20 4.50 9.00 5.00 5.56 18.00 4.72 5.06 10.00 5.56 6.18 20.00 5.25 5.62 11.00 6.11 6.80 22.00 5.77 6.19 12.00 6.67 7.41 24.00 6.30 6.75 *Price per 100 square feet at a given price per box of 112 sheets Cost of laying not included. CHAPTER XII PRACTICAL TABLES Explanation of Tables. Tables are very useful, and in technical books indispensable, especially when they are all pertinent to the subject. A conscientious effort has been made to keep the present work free of the encumbrance of irrelevant tables. The few included herein have been found indispensable. They are believed to be accurate but not necessarily complete, though sufficient for all practical purposes. Table XXVII, " Thermometric Equivalents," converts the Fah- renheit temperature scale into the Centigrade scale and vice versa. This is often necessary in the laboratory and in the field. Table XXVIII gives the relative values of density and specific gravity of liquids heavier than water. Table XXIX, " Specific Gravity and Baume for Liquids Lighter than Water," shows the relation of density, as recorded on the Baume scale, to specific gravity of liquids lighter than water. Every liquid lighter than water has a definite specific gravity at a certain temperature, and in consequence a definite density which is usually measured by the hydrometer and expressed on the Baume scale. Some liquids, such as petroleum oils, when distilled at and to a cer- tain temperature, give off volatile oils, which leave the residue denser than the original; this denser composition is indicated by a corre- spondingly higher reading on the Baume" scale. This reading may be transformed, by means of the table, into an equivalent specific gravity of that liquid for that temperature. Table XXX, " Specific Gravity and Coefficient of Expansion of Various Materials," is compiled from the most reliable sources. Some of the values are not to be found in any book, having been obtained from research laboratory tests. A knowledge of the rela- tive expansion and contraction of mineral and organic solids and liquids is often necessary in waterproofing engineering. Table XXXI, " Weight and Thickness of Burlap, Felt, and Cot- ton Fabric Membranes with Coal-tar Pitch Binder," is based on water- proofing membranes made only with coal-tar pitch binder. If 379 380 WATERPROOFING ENGINEERING O o o -* OCDtOOO5Oi-H(NC3Tt-OOO5O'-l(NO'5 t^OOOOOOOOOOOOOOOOOOOOO5O5O5ClOO5O5O2O3O5OOOOOOOOOOOi-i'-i'-li-H IN iMOOOOOr^^'-^'--i'--i(N(N(N(N(N(NC 1 OCOOOC y 3COCOTf'-COOOOlN'*Cl>05'-HfO-*COt B5owtbrt*-N.tooooo6oooooo>o>Spppo< OOCOrJON COCO^IN COCOON 00 CO * (N 00 CO ^ t^ O I-H < )OOGO05< ^H rH ^H i-H ^H i-l IN IN l^ O5 O5 O iO CO t^ 00 O CO Tj< O CO l> O O CD TJH i 1 1> CO I-H (N Tt* l> rH ^-1 ^H ^H l> 1-1 t-H 00 CO * ^f t^ 1> O5 Oi >O O I-H l> l> TH 00 >O O O O O -y , . ' ' &'Si'Si'Hi'3<'2< -^ric^C^COCOTtlTtilOlOCOO 038 g 7 oz.; henc 0.59, and 0.59 ong, weig tively, 0.5 of the fabric. The volume of the open meshes r cent of the voids of the untreated jute burlap. =5.34 lb. lling the open mes cu. in., or about 40 ^ : % i |s1^. o P rj '.S 1 *- d ili^l O o :> -S ^33 ^ i^lTJU i iil! safi OJ3^ O a ts5- ..ST. -a si-4J c .o -SC-.2.S i OT* ! Bite Mi! S - l-S-g a i Ji2i i ^1^1^ ' a l a -|nfs S |q~ *a S 5 *^ *O fl_ J3 fi J3-- m . MM 3 ^g|SS|-|'s ^S H ^.-d * a e ^ c TS >> fi ? PRACTICAL TABLES 389 in themselves, they merely furnish " body," depth and weight to the envelope and economy in the waterproofing system. The bitu- minous mastic alone is the waterproofing medium, hence the more of it present within economical limits, of course the better. The smallest joint should be not less than f inch and the largest need not be more than J inch. Therefore the volume and weight of the various ingredients have been calculated on this basis; also on the empirical basis of a 20 per cent and 30 per cent reduction in volume of mastic, as compared to volume of ingredients (see Chapter VII), mixed in proportions of 2 : 1 : 1 and 1 : 1 : 1, respectively. TABLE XXXII. THICKNESS OF WATERPROOFING MATERIALS REQUIRED FOR DIFFERENT WATER PRESSURES NUMBER OF PLIES, LAYERS OR COURSES. PORTLAND CE- Jo* 02 MENT MORTAR . *g> -2 vS 3 ' C *'o'~' "^_S S S3 J3 J5-I .flfr Uni 3 "-5 d -C W .^SJ "* i a o - q o - 49 +J P*H *+"* S" -+^> ^ TJ r-- 'C Cxj -"tn fi ^^ ^* ^ -^ ' DO *-D cc I *3 ll 1 a 03 jo' a *.2 ..g c3 "** i| 1 o a O CJ O X N -^ -+^ ^ c? -*^> -^ "08 ^ ,0 'aSXJ ^gg Q tl ^ CQ ^ PH O i^lc "^ ^"lc ^ ^"o ^3 o3 rJS 03 -^^H c3 ^J, *03 tu 03 ^ |0 Cg^y. ft p,pr^ gft ft^ *o -2 o ^^ *~* _-i i H 3 ^ K C w -A II s| H""^ = o w o S2's- f^^E k (MO(NiC(M-^O 00 *O CO OS CO OS OS CO OS CO t^- CO OS 00 l^ T-I CO i I CO TH CO 1-1 i i CO CO CO CO CO CO CO CO t O OS CO i-< 00 OS CO CO CO CO CO CO CO CO iO O j^, f> CO CO CO CO O00r-oooTt.i THCOCOiO^COr-icOTH^cOt^Tt W l>- T-I I> I-H l> l> I-H d I-H CO O T-H O i i i ' CO i 00 i i 00 . COCO a CJ cc O5 00 00 CO CO CO OS h- OOCOi 3 ^ i-HCOCOiOr-iCO' iCOCOOiiOOOCOOSiOOO COCO: *> I ooodoooococoioioco'coioio cool ^ -g . ^Q J3 cococoooocc'-i^ osi-H icS i-Hcoi-^coOi 'i (coos' oooos' IGCO cocoi ^ o . . . . . I O u rHCOCOCOi-HCOCOCO '-tCO i J||''o ; S S N-l I || o 00 ^<* * O . I .5 f *^ 3 O SO t^. 00 CO ' O SO ** c^ i-< o as oo b- so O SO O *^ O ^i . f^i . ^ f^ . /3 ^^ ^H . f^ . UJ^ f^i f^i . f^ 4-^ O5 00 i^* 1^* * SO SO *O *O ^t^ ^^ CO ' CO C^ Tt -OCOO n . ^Q . ^Q . . I.Q . ^H . ^^ . 00 IO -C5 -O '00 -O O1 i i O 'O O Cq| -to -O -CO -t>- -i-HOOO- CO N o Q O CO C^ T^ 05 0i GO H.2 si rH 51 -*. 1C 00 1C -IN O OS 00 | rH rH - rH . rH O O 1 o p . : : : IN O OS 00 : : : _; ' ' ,-j d d : ! 6 ^^ O Sg : i-HfNCO-^iC -COt^-OOOS s Q H Ig S S COi-iOOCOCO -i-HTtHQO(M ic rt< c^i i ^o -osoOi^-b- * 5 |q i-J 00 > W O |i 2g : 898X8 :8K88 : i o ; & KS : QOiQ(NOOO -iOO>(NCO - COC^i-nOOO t> CO CO O ' s K ,j)OQ H d 1 ! 2 : T^ C^ CO ^^ *O CO t*^ 00 O^ M o ^J2 c a d d fc^ i m 3 H 1 i 83 o t. B .2 QQ to j 1 O O t, | A 1 a 3 1 M 3 S3 O 03 B w si 1 O 43 M c s 1 2d 1 12 411 3d li 13 429 f i 8 A 10 f 13 714 31 li 10| 225 4d li 12 274 7 8 i 8 A 10 1 12 469 4d li 10| 187 5d if 12 235 1 1 8 A 10 1 12 411 5d if 10 142 Qd 2 12 204 li 1 8 A 10 li 13 365 Qd 2 9 103 7d 2i 11 139 li i 8 A 10 li 11 251 Sd 2J 11 125 li I 8 TS 10 if 10 230 Qd 2f 11 114 if i 8 A 10 li 10 176 lOd 3 10 83 . . . . , . . if 10 151 2 9 103 * As manufactured by Pittsburgh Steel Co. APPENDICES APPENDIX I EXPLANATION OF MECHANICAL ANALYSIS* FOR GRADING CONCRETE AGGREGATES MECHANICAL analysis consists in separating the particles or grains of a sample of any material, such as broken stone, gravel, sand or cement, into the various sizes of which it is composed, so that the material may be represented by a curve (see Figs. 139-140), each of whose ordinates is the percentage of the weight of the total sample which passes a sieve having holes of a diameter represented by the distance of this ordinate from the origin in the diagram. The objects of mechanical analysis curves as applied to concrete aggregates are (1) to show graphically the sizes and relative sizes of the particles; (2) to indicate what sized particles are needed to make the aggregate more nearly perfect and so enable the engineer to improve it by the addition or substitution of another material; and (3) to afford means for determining best proportions of differ- ent aggregates. To determine the relative sizes of the particles or grains of which a given sample of stone or sand is composed, the different sizes are separated from each other by screening the material through succes- sive sieves of increasing fineness. After sieving, the residue on each sieve is carefully weighed, and beginning with that which has passed the finest sieve, the weights are successively added, so that each sum will represent the total weight of the particles which have passed through a certain sieve. The sums thus obtained are expressed as percentages of the total weight of the sample and plotted upon a diagram with diameters of the particles as abscissae and percentages as crdinates. A convenient outfit for such a mechanical analysis as above described, consists of a set of sieves, an apparatus for shaking the sieves, and scales for weighing. A standard size of sieve is 8 inches in diameter and 2J inches high. Sieves with openings exceeding 0.10 inch are preferably made of spun hard brass with circular * Taylor and Thompson " Concrete, Plain and Reinforced," p. 193. 399 400 APPENDIX I openings drilled to the exact dimensions required. Sieves with open- ings of 0. 10 inch and less are preferably of woven brass wire set into a hard brass frame. Woven brass sieves are made for many purposes, and are sold by numbers which are approximately the number of meshes to the linear inch. As the actual diameter of the hole varies with the gauge of wire used by different manufacturers, every set of sieves must be separately calibrated. The number and sizes of sieves to be used depends upon the im- portance of the testing to be done. A convenient set of sieves for ordinary laboratory practice is given below in Table XL. TABLE XL. SIZES OF SAND AND STONE SIEVES Stone Sieves, Diameter of Hole (Inches). SAND SIEVES. Commercial No. Diameter in Inches. Hole. Wire. 3 00 2.50 1 in. round No. 7 0.032 0.111 2.00 " 12 0.056 0.027 1.50 " 20 0.0335 0.0165 1.00 " 30 0.0198 0.0135 0.75 " 50 0.0120 0.0080 0.50 " 90 0.0059 0.0052 0.25 " 200 0.0029 0.0021 When many analyses are to be made, it is convenient to have a printed cross-section form, with appropriate spaces for filling in the number of the analysis, description of the material, location of the work, and other facts relating to the material. For those who are unfamiliar with mechanical analysis, a detailed explanation of the method of locating the curve is here given. The method can best be understood by referring to the diagrams of typical materials which are also of practical interest as illustrating the curves which may be expected in special cases. Fig. 139 represents a typical mechanical analysis of crusher-run micaceous quartz stone which has been run through a J-inch revolv- ing screen so as to separate particles finer than \ inch, that is, the dust for use with sand. For a sample of stone, which may be taken by the method of quartering * 1000 grams is a convenient quantity for 8-inch diameter * The method of quartering consists in taking shovelfuls of the material from various parts of the pile, mixed together and spread in a circle. The circle is quartered, as one would quarter a pie; two of the opposite quarters are shoveled GRADING CONCRETE AGGREGATES 401 sieves 2J inches in depth, and also permits of easy reduction from weights to percentages. To obtain the analysis shown in Fig. 139, the sample of stone is placed in the upper (coarsest) sieve of the nest of stone sieves given in Table XL, and after 1000 * shakes the nest is taken apart, and the quantity caught on each sieve is weighed, beginning with the finest and placing each successive residue on the scale pan with that already weighed. The results obtained in the particular case under consideration are illustrated in Table LXI, which shows the method of finding the percentages: 55 o3 -- ven Diameter s i 2 2 o 3 o o' -< -H PARTICLES BELOW K INCH SIEVED OUT FOR USE AS SAND \ X f lx / x s / ercent, by Weight, Smaller than gi 8 J / X ,J, ,-v' X ' A V X v , " / ^ x .tea X I X C S X / ^ ^ -* 0.25 0.50 0.75 1.00 1.25 Diameters of Stone in Inches 1.50 1.75 2.00 FIG. 139. Typical Mechanical Analysis Curve of Crusher-run Micaceous Quartz Stone. The various percentages are plotted on the diagram and the curve drawn through the points. The vertical distance from the bottom of the diagram to the curve, that is, the ordinate at any point, represents the percentage of the material which passed through a single sieve having holes of the diameter represented by this particu- lar ordinate. Since the percentage of material passing any sieve is always the complement of the percentage of grains coarser than that sieve, the vertical distances from the top of the diagram down to the curve represents the percentages which would be retained away from the rest, thoroughly mixed, spread, and quartered as before. The operation is repeated until the quantity is reduced to that required for the sample. * In practice to-day the custom prevails of shaking the material until no more comes through as determined by successive weighings. 402 APPENDIX I upon each sieve if employed alone. For example, taking 1.25, 62 per cent, the distance from the bottom of the diagram, represents the percentage of material finer than IJ-inch diameter, and 38 per cent, the distance down from the top of diagram, represents the percent- age coarser than 1J inch. TABLE XLL RESULTS OF SCREENING SAMPLES OF STONE OF FIG. 140 Size Sieve. Amount Finer than Each Sieve. Percentage Finer than Each Sieve. Inches Grams Per Cent 1.50 801 80 1.00 457 46 0.67 222 22 0.45 99 10 0.30 27 3 0.20 19 2 0.15 8 1 0.10 Typical curves of a fine, a medium well graded, and a coarse sand are shown in Fig. 140. For convenience in plotting, the horizontal 0.025 0.050 0.075 0.100 0.125 Diameters of Sand in Inches 0.150 0.175 0.200 FIG. 140. Typical Mechanical Analyses Curves of Fine, Medium, Well-graded, and Coarse Sands. scale is ten times greater than that of Fig. 139, the diagram showing diameters ranging from to 0.200 inch diameter. The mechanical analysis of crusher dust is apt to vary between the curves of fine sand and medium sand which are shown in Fig. 140. APPENDIX II CONCRETE IN SEA WATER* REGARDING the chemical action of sea water on concrete and its prevention, the following information and conclusions are presented here because of their bearing on and corroboration of the subject matter of Chapter I.f Investigations concerning the effect of sea water on concrete immersed for periods up to fifty years or more; of the relative merits of standard Portland cement and Portland cement made with dif- ferent proportions of its principal constituents, in resisting the dis- integrating effect of sea water; of the effect of varying the propor- tions of cement in the mortar and concrete; of differently graded aggregates; of the addition of various finely ground materials to the cement after burning; of the relative durability of concrete cast in place as compared with concrete blocks allowed to harden before placing in the sea ; and of the effect of various materials added to the concrete mixture to produce impermeability and consequent increased durability, have been made in European countries and in America. Regarding the chemical action of sea water on cement, the fol- lowing conclusions are presented: Cement containing up to 2J per cent of sulphuric anhydride (SOs) resists the action of sea water fully as well as cement with lower sulphuric anhydride content. While all the hydraulic cements now in use are liable to decomposi- tion in sea water, Portland cement is the one to be preferred in every respect. High iron Portland cement and puzzolan cement have failed to show superiority over standard Portland cement in resisting the disintegrating effect of sea water. * American Railway Engineering Association, Vol. 15, March, 1914, p. 564. t For a presentation of practical results of marine construction and valuable conclusions drawn from observed effects of sea water on concrete all over the United States, see five articles by Rudolph J. Wig and Lewis R. Ferguson in Engineering News-Record, commencing Vol. 79, No. 12, 1917. 403 404 APPENDIX II Regarding the effect of varying the proportions of cement in the mortar and concrete, in general, the richer mixtures have been found to offer better resistance to the attack of sea water. Proportions recommended for mortars are those with one part cement to one part of sand up to one part cement to two parts sand. The bad condi- tion of mortars leaner than the above after exposure in sea water, stands out prominently. In the use of reinforced concrete for maritime works, it is advis- able to employ larger proportions of cement than are usual for similar works in fresh water. Concerning the addition of finely ground material to the cement after burning, it has been found that the addition of ground puzzolan or furnace slag to Portland cement increases the resistance of the resulting mortar or concrete to the disintegrating effect of sea water. Regarding the use of any material added to the concrete mix- ture in small quantities in order to reduce permeability, no results of practical working tests have demonstrated that the effect of any material in reducing permeability is other than mechanical, i.e., to supply a deficiency in fine material in a poorly graded concrete mixture. Allowing the concrete to harden under favorable conditions before exposure to the action of sea water greatly increases its resistance to attack by the sea water and is recommended wherever possible. When concrete is deposited under sea water, such precaution should be observed as will prevent the washing of the cement from the mixture. Forms should be so tight as to prevent the entrance of sea water after depositing the concrete, in order that a smooth dense surface may be obtained. The combined effect of freezing and of sea water is noted on marine structures in northern latitudes between high and low tide levels. Under these conditions the disintegrating effects are par- ticularly severe. Dense, properly hardened concrete is not affected by the action of sea water. Where the concrete is porous, however, it is likely to be damaged by frost action, especially between tides. There is no evidence, however, that porous concrete is damaged by sea water in latitudes where there is no frost. The making of a dense, impermeable concrete by the use of a well-graded aggregate, rich mixture, proper consistency, and good workmanship, and allowing the concrete to harden under favorable conditions before being exposed to the action of sea water, is generally CONCRETE IN SEA WATER 405 conceded to be an efficient means of satisfactorily insuring the pres- ervation of concrete in maritime works. Concrete Subjected to the Action of Water Containing Alkalies. Investigations concerning the effect of ground waters which contain alkalies on concrete have disclosed several instances of apparent disintegration. The following points have been demonstrated in regard to the resistance of concrete to these agencies : Concrete in which poor aggregates and lean mixtures have been used and in which the material has been carelessly placed, when coming in contact with alkali seepage may be affected thereby. The aggregates should be composed of materials inert to alkalies present in the water. A chemical examination of the sand from coun- try known to contain alkaline soils is recommended. Water containing substances known to react with the elements of the cement should be kept from coming in contact with concrete until the latter has thoroughly hardened. Care should be taken to provide a smooth surface and sufficient slope to the extrados of the arch of tunnel linings when the ground- water level lies below the tunnel grade to facilitate the flow of seep- age water to the sides. The back filling over the arch should consist of porous material such as coarse, crushed stone, for the same reason. Side-drains should be used where necessary and connected with an underdrain, which should be provided in all cases. The measures to be used in making concrete which is to be exposed to the action of these deteriorating agencies in order to prevent disintegration are the same as recommended for sea water construc- tion. Impermeability is the prime requisite, and the results of experi- ments and practical tests indicate that concrete, carefully prepared, is just as resistant, if not more so, than if mixed with foreign materials or special preparations. The following instructive conclusions on the effect of sea water on concrete are from a paper by Mr. W. Walters Pagon, read before the Engineers Club of Baltimore.* Though somewhat a repetition of the previous paper, its greater detail warrants its addition here. In order to construct concrete that will have the greatest resistive power against the action of sea water (and also probably of alkali waters) it must possess the following characteristics: The addition of puzzolan in some form is widely practiced in Europe and appears to be theoretically correct. It has not been tried in America, to the author's knowledge, but is worth an exhaus- * " Concrete," Vol. 9, No. 4, October, 1916. 406 APPENDIX II tive test. The amount should not be over one part nor less than one-half part for each part of cement. Waterproofing with substances that combine chemically with the free lime ought to be successful and is worth testing. Between extreme high and low tides the concrete surface should be faced continuously, without joints, with about 3 inches of 1 : 1J or 1 : 2 mortar made with sand as specified below, well cured before coming in contact with the sea water. Facing must be placed simul- taneously with the backing. The cement should be low in lime and alumina and contain as little gypsum as possible. Sand must be silicious, uniformly graded from fine to coarse, with not less than 50 per cent nor more than 70 per cent passing through a No. 20 sieve, and no more than 3 per cent passing a No. 100 sieve and must have no organic matter coating the grains. It must be free from roots and easily disintegrated grains, such as feldspar, shells, limestone, mica, etc. It should be washed free from clay, and should show a tensile strength for 1 : 3 specimens not less than the following percentages of the strength of standard Ottawa sand of the same consistency, using the brand of cement that is to be used on the work: A Percentage A e - Strength. 1 day 85 7 days 95 28 days 100 Where concrete must be exposed to sea water without mortar facing, gravel should not be used. Broken stone should be hard, durable trap, granite or other dense, hard, insoluble stone. It should not exceed f inch in size and should be free from crusher dust, sand, dirt, organic matter or other foreign substances. The mixture should be 1 : 1J : 3 or 1 : 2 : 4 or should be proportioned for maximum density. Pure fresh water should be used in sufficient quantity to permit the materials to be well puddled and spaded, so that no later surface treatment or patching will be require^, but not sufficient to materially retard the setting of the cement. Care must be exercised, however, to prevent the formation of laitance or pockets of neat cement or very rich mortar. Forms should be tight to prevent leakage of cement, or, where concrete must be submerged immediately, to prevent contact with the sea water. CONCRETE IN SEA WATER 407 Facing should be reinforced with steel well covered with mortar and securely anchored to the backing. No surface treatment should be given. The work should be allowed to harden for two weeks, if possible, before coming in contact with sea water. Two months is better. Sea water work should never be done in cold weather, with tem- perature below 40 deg. Fahr. (4.4 deg. Cent.). Where possible, pre-cast, mortar-faced blocks cured in damp sand for at least one month should be used. The mortar facing should not only be on the outside of the block, but should extend on the faces which form the bed joints and vertical joints. In this way the facing will be continuous, back to such a point, that no water can get into the rear of the block. The joints between the blocks should be pointed with 1 : 1 mortar of coarse sand to eliminate saturation. The most durable surface will be obtained if granite or other dense stone be used as facing. This should not be less than 6 inches thick, anchored back with wrought-iron clamps and pointed with 1 : 1 mortar of coarse sand and cement as noted above. On mortar or concrete surfaces the growth of barnacles, moss, etc., will frequently afford protection. APPENDIX III REPORT ON WATERPROOFING * THE following report of Committee D-8 of the American Society for Testing Materials corroborates the author's information and experience in general waterproofing preceding and since its publica- tion. The committee reports that while it has not been able to arrive at sufficiently definite conclusions to enable it to formulate specifica- tions for the making of concrete structures waterproof or for materials to be used in such work, it has reached certain general conclusions which may be of assistance to the constructor in securing the desired result of impermeable concrete. Early in the investigation, the work was found to sub-divide naturally into three branches, and the conclusions reached will be grouped in order under these sub-divisions, which are: 1. The determination of causes of the permeability of concrete as usually made from mixtures of Portland cement, sand and stone, or other coarse aggregate, in proportions of from 1 cement, 2 sand and 4 stone, to 1 cement, 3 sand and 6 stone, and the best methods of avoiding these causes. 2. The rendering of concrete more waterproof by adding to ordi- nary mixtures of cement, sand and stone, other substances, which, either by their void-filling or repellent action, would tend to make the concrete less permeable. 3. The treatment of exposed surfaces after the concrete or mortar has be3n put in place and hardened more or less, either by penetra- tive, void-filling or repellent liquids, making the concrete itself less permeable or by extraneous protective coatings, preventing water having access to the concrete. Considering these several sub-divisions separately and in the order named, the committee finds : 1. Causes of Permeability of Concrete. In the laboratory and under test conditions using properly graded and sized coarse and fine aggregates, in mixtures ranging from 1 cement, 2 sand and 4 stone, to 1 cement, 3 sand and 6 stone, impermeable concrete can invariably * Proceedings, American Society for Testing Materials, Vol. 13, 1913, p. 459. 408 REPORT ON WATERPROOFING 409 be produced. That even with sand of poor granulometric composi- tion, with mixtures as rich as 1 cement, 2 sand and 4 stone, per- meable concrete is seldom, if ever, found and is a rare occurrence with mixtures of 1 cement, 3 sand and 6 stone. But the fact remains, nevertheless, that the reverse obtains in actual construction, per- meable concretes being encountered even with 1 cement, 2 sand and 4 stone mixtures and are of frequent occurrence where the quantity of the aggregate is increased. This we attribute to: (a) Defective workmanship, resulting from improper propor- tioning, lack of thorough mixing, separation of the coarse aggregate from the fine aggregate and cement in transporting and placing the mixed concrete, lack of density through insufficient tamping or spading, and improper bonding of work joints, etc. (6) The use of imperfectly sized and graded aggregates: (c) The use of excessive water, causing shrinkage cracks and for- mation of laitance seams. (d) The lack of proper provision to take care of expansion and contraction, causing subsequent cracking. Theoretically, none of these conditions should prevail on properly designed and supervised work, and are avoided in the laboratory and in the field, under -test conditions, where speed of construction and cost are negligible items, instead of being governing features as they must be in actual construction. Properly graded sands and coarse aggregares are rarely, if ever, found in nature in sufficient quantities to be available for large construction, and the effect of poorly graded aggregates in producing permeable concrete is aggre- vated by poor and inefficient field work. Even if we could afford the added expense of screening and remixing the aggregates so as to secure proper granulometric composition to give the density required and to make untreated concretes impermeable, it is seemingly a commercial impossibility on large construction to obtain workman- ship even approximating that found in laboratory work. It there- fore seems that we can secure impermeable concrete most economic- ally by adopting some special waterproofing treatment. 2. Addition of Foreign Substances to Cement or During Mixture. The committee finds that in consequence of the conditions outlined above, the use of substances calculated to make the concrete more impermeable, either incorporated in the cement or added to the con- crete during mixing, has become general. This has resulted in the development and placing on the market of numerous patented or proprietary waterproofing compounds, the composition of which is more or less of a trade secret. 410 APPENDIX III While it has been impossible for the committee to test all of the special waterproofing compounds being placed on the market, it has investigated a sufficient number of these, as well as the use of certain very finely divided, naturally occurring or readily obtainable com- mercial mineral products, such as finely ground sand, colloidal clays, hydrated lime, etc., to form a general idea of the value of the different types. The committee finds: (a) That the majority of patented and proprietary integral com- pounds tested have little or no permanent effect on the permeability of concrete and that some of these even have an injurious effect on the strength of mortar and concrete in which they are incorporated ; (6) That the permanent effect of such integral waterproofing additions, if dependent on the action of organic compounds, is very doubtful; (c) That in view of their possible effect, not only upon the early strength, but also upon the durability of concrete after considerable periods, no integral waterproofing material should be used unless it has been subjected to long-time practical tests under proper observa- tion to demonstrate its value, and unless its ingredients and the pro- portion in which they are present are known; (d) That in general, more desirable results are obtainable from inert compounds acting mechanically than from active chemical compounds whose efficiency depends on change of form through chemical action .after addition to the concrete; (e) That void-filling substances are more to be relied upon than those whose value depends on repellent action; (/) That, assuming average quality in sizing of the aggregates and reasonably good workmanship in the mixing and placing of the concretes, the addition of from 10 to 20 per cent of very finely divided void-filling mineral substances may be expected to result in the pro- duction of concrete which under ordinary conditions of exposure will be found impermeable, provided the work joints are properly bonded, and cracks do not develop on drying or through change in volume due to atmospheric changes, or by settlement. 3. External Treatments. While external treatment of concrete would not be necessary if the concrete itself, either naturally or by the addition of waterproofing material, was impermeable to water, it has been found in practice that in large construction, no matter how carefully the concrete itself has been made, cracks are apt to develop, due to shrinkage in drying out, expansion and contraction under change of temperature, moisture content and through settle- ment. REPORT ON WATERPROOFING 411 It is, therefore, often advisable on important construction to anticipate and provide for the possible occurrence of such cracks by external treatment with protective coatings. Such coating must be sufficiently elastic and cohesive to prevent the cracks extending through the coating itself. The application of merely penetrative void-filling liquid washes will not prevent the passage of water due to cracking of the concrete. The committee has, therefore, divided surface treatments into two heads: (a) Penetrative void-filling liquid washes. (6) Protective coatings, including all surface applications intended to prevent water coming in contact with the concrete. While many penetrative washes are efficient in rendering concrete waterproof for limited periods, their efficiency is apt to decrease with time and it may be necessary to repeat such treatment. Some of these washes may be objectionable, due to discoloring the surface to which they are applied. The committee, therefore, believes that the first effort should be made to secure a concrete that is impermeable in itself and that penetrative void-filling washes should only be re- sorted to as a corrective measure. While protective extraneous bituminous or asphalt coatings are unnecessary, so far as the major portion of the concrete surface is concerned, provided the concrete either in itself or through the addi- tion of internal compounds is made impermeable, they are valuable as a protection where cracks develop in a structure. It is therefore recommended that combination of the two methods integral and extraneous waterproofing be adopted in especially difficult or im- portant work. Considering the use of bituminous or asphaltic coatings, the com- mittee finds: (a) That such protective coatings are often subject to more or less deterioration with time, and may be attacked by injurious vapors or deleterious substances in solution in the water coming in contact with them. (6) That the most effective method for applying such protec- tion is either the setting of a course of impervious brick, dipped in bituminous material, into a solid bed of bituminous material, or the application of a sufficient number of layers of satisfactory membra- nous material cemented together with hot bitumen. (c) That their durability and efficiency are very largely dependent on the care with which they are applied. Such care refers particularly to proper cleaning and preparation of the concrete to insure as dry a surface as possible before applica- 412 APPENDIX III tion of the protective covering, the lapping of all joints of the mem- branous layers, and their thorough coating with the protective mate- rial. The use of this method of protection is further desirable because proper bituminous coverings offer resistance to stray electrical cur- rents. So far, the committee has considered only concretes of the usual proportions, namely, those ranging from 1 cement, 2 sand and 4 stone, to 1 cement, 3 sand, and 6 stone. It has been suggested that im- permeable concretes could be assured by using mixtures considerably richer in cement. While such practice would probably result in an immediate impermeable concrete, it is believed by many that the advantage is only temporary, as richer concretes are more subject to check cracking and are less constant in volume under changes of conditions of temperature, moisture, etc. Therefore, the use of more cement in mass concrete would cause increased cracking, unless some means of controlling the expansion and contraction be dis- covered. With reinforced concrete the objection is not so great, as the tendency to cracking is more or less counteracted by the re- inforcement. It has also been suggested that the presence in the cement of a larger percentage of very fine flour might result in the production of a denser and more impermeable concrete, through the formation of a larger amount of colloidal gels. Neither of these suggestions have been especially investigated by the committee. Both appeal to the committee, however, for the reason that they substitute active cementitipus substances for the largely inactive void-filling materials previously recommended, thus increasing the strength of the concrete. In conclusion, thp committee would point out that no addition of waterproofing compounds or substances can be relied upon to completely counteract the effect of bad workmanship, and that the production of impermeable concrete can only be hoped for where there is determined insistance on good workmanship. APPENDIX IV GLOSSARY OF TERMS USED IN THE WATERPROOFING INDUSTRY Acid Sludge. A waste mixture of sulphonated hydrocarbons resulting from the treatment of bitumens with sulphuric acid. Aggregate. The inert material, such as sand, gravel, shell, slag or broken stone, or combinations thereof, with which the cementing material is mixed to form a mortar or concrete. Albertite. A soft jet black mineral (asphaltic hydrocarbon) derived from petroleum by natural oxidation, obtained in Canada. Alum. A white crystalline substance consisting of a hydrated double sul- phate of aluminum and potassium. See Chapter V. Anthracene. A waxy crystalline hydrocarbon found principally in coal tars. Artificial Bitumens. Hydrocarbon residues produced by the partial or frac- tional distillation of bitumen. Artificial Gilsonite. A product obtained from the distillation of a mixture of fish remains and wood and redistillation of the resulting oil. Asbestine. A trade name for a certain grade of powdered asbestos used in paints as a filler. Asbestos. A mineral of fibrous crystalline structure composed, chemically, of silicates of lime and magnesia, and alumina. See Chapter V. Asbestos Felt. Sheets made of asbestos shreds. See Chapter V. Ash Water Glass. Same as water glass. Asphalt. Solid or semi-solid native bitumens, solid or semi-solid bitumens obtained by refining petroleums, or solid or semi solid bitumens which are combi- nations of the bitumens mentioned with petroleums or derivatives thereof, which melt on the application of heat, and which consist of a mixture of hydrocarbons and their derivatives of complex structure, largely cyclic and bridge compounds. Asphalt Cement. A fluxed or unfluxed asphaltic material, especially prepared as to quality and consistency. Asphalt Mastic. A term frequently applied to refined asphalt, particularly to that obtained from bituminous rocks. A mixture of fine mineral matter and asphalt. Asphalt Pavement. A pavement composed of a mixture of asphalt and sand or powdered mineral dust or both. Asphalt Putty. A mixture of a liquid and a -solid asphalt (and fine mineral matter, usually) or asphalt and coal-tar pitch, having a particular consistency. Asphaltenes.* The components of the bitumen in petroleum, petroleum products, malthas, asphalt cements, and solid native bitumens, which are soluble in carbon disulphide, but insoluble in paraffin naphthas. Asphaltic. Similar to, or essentially composed of, asphalt. * Adopted by the American Reporters on Communication No. 10 at the third International Road Congress. 414 APPENDIX IV Asphaltic Coal. Solid forms of asphalt (originally derived from petroleum) which, through loss of their oil content, by oxidation, resemble glance coal. Asphaltic Concrete. Broken stone bound together with asphaltic cement. Asphaltic Limestone. Limestone or limestone sands naturally impregnated with asphalt or maltha, and known as " asphalt " in Europe. Asphaltic Oils. Asphaltic petroleums. Asphaltic Petroleums. Petroleums containing an asphaltic base. Asphaltic Sandstone. Sandstone naturally impregnated with asphalt or maltha and known as " asphalt " in Europe. Asphaltite. Same as asphaltic coal. Asphaltum. The Latin form of the English word asphalt. Bakelite. A hard amber-like substance manufactured from the coal-tar derivatives phenol and formaldehyde. See Chapter V. Bank-run Gravel. The normal product of a gravel bank. Barret Specification Felt. Trade name for a proprietary tar-treated roofing felt. Baume Gravity. An arbitrary scale of specific gravity or density of liquids, usually expressed as deg. Baume, or B. on a hydrometer. See Chapter XII. Benzene. Benzol (C 6 H 6 ). See Chapter V. Benzine. A light and volatile fraction of petroleum. See Chapter V. Benzol. A light, volatile, colorless coal-tar distillate of the formula C fi H R . See Chapter V. Bermudez Asphalt. A very pure semi-solid native asphalt from Bermudez. Binder. The bituminous cementing material employed in the membrane system of waterproofing. Bitumen. A natural hydrocarbon mixture of mineral occurrence, widely diffused in various forms which grade by imperceptible degrees from a light gas to a solid; commercially the term includes only the heavy liquid and solid asphalts. Frequently coal-tar pitch is so referred to. Bituminous. A term applied to materials containing bitumen. Bituminous Cement. A bituminous material suitable for use as a binder having cementing qualities which are dependent mainly on its bituminous char- acter. Bituminous Emulsion. A mixture of a bituminous oil and water made miscible through the action of a saponifying agent or alkaline soap. Bituminous Paints. Mixtures of liquid paraffin and asphalt or coal-tar; mixtures of bitumen with some drying oil. See Chapter V. Bituminous Putty. A mixture of bituminous materials and whiting or other mineral, of a putty-like consistency. Bituminous Rock. Same as rock asphalt. Blown Asphalt. Asphalt through which air has been blown during the process of refining. Blown Oils. Blown petroleum. Blown Petroleum.* Semi-solid or solid products produced primarily by the action of air upon originally fluid native bitumens which are heated during the blowing process. Building Paper. A paper, usually a heavy grade and strong, sized with rosin to make it water resisting and used to sheath buildings to exclude drafts. *Adopted by the American Reporters on Communication No. 10 at the third International Road Congress. GLOSSARY OF TERMS USED IN WATERPROOFING 415 Built-up Roofs. Roofing consisting of several plies of treated felt cemented with asphalt or coal-tar pitch. See Chapter III. Burlap. A woven fabric made of jute. See Chapter V. Byerlite. Common and trade-name of a blown asphaltic petroleum dis- tinguished from ordinary blown petroleums principally by the use of oxygen in- stead of air in the blowing process. Caffall Process. A proprietary process for applying paraffin to exterior masonry surfaces. Calcium Compounds. Salts of metal calcium or lime. See Chapter V. Caoutchouc. A hydrocarbon with the approximate formula of CioHi 6 and possessing properties similar to India rubber. Carbenes.* The components of the bitumen in petroleums, petroleum products, malthas, asphalt cements, and solid native bitumens, which are soluble in carbon disulphide, but insoluble in carbon tetrachloride. Carbon Bisulphide. The volatile and extremely inflammable compound of carbon and sulphur (CS 2 ) . Carbon Disulphide. Same as carbon bisulphide. Carbon Tetrachloride. A volatile noninflammable compound of carbon and chlorine (C-Cl t ). Carborundum. An artificial abrasive material resulting from the burning, in an electric furnace, of a mixture of sand, coke, sawdust and salt. Casein. An albumin found in milk. See Chapter V. Cement. An adhesive substance used for uniting particles of materials to each other. Ordinarily applied, only to calcined " cement rock," or to arti- ficially prepared, calcined, and ground mixtures of limestone and silicious mate- rials. Sometimes used to designate bituminous binder used in waterproofing. Cement Floor. A name commonly applied to concrete floors with or without a mortar top. Cerasin. Ozocerite. Cerite. Ozocerite. China Clay. Kaolin. Chinawood Oil. Oil pressed from the seeds of the wood-oil tree of China and Japan. See Chapter V. Choctaw. Name of mining locality (in Oklahoma) of grahamite; some- times, but incorrectly used for grahamite. Clay. Finely divided earth, generally silicious and aluminous, which will pass a 200-mesh sieve. Coal Tar. The mixture of hydrocarbon distillates, mostly unsaturated ring compounds, produced in the destructive distillation of coal. See Chapter V. Coal-tar Pitch. The residue (of a viscous consistency) resulting from the distillation of coal-tar. See Chapter V. Coat. (1) The total result of one or more surface applications. (2) To apply a coat. Coke-oven Tar. Coal tar produced in by-product coke ovens in the manu- facture of coke from bituminous coal. See Chapter V. Colloidal Material. A gelatinous substance, resembling glue or jelly, and consisting of microscopically fine particles of matter. Colophony. Rosin. * Adopted by the American Reporters on Communication No. 10 at the third International Road Congress. 416 APPENDIX IV Compressed Asphalt. A European (particularly French) term for rock asphalt pavement. Concrete Floor Hardener. A powdered metal or mineral usually troweled on, or a liquid chemical reagent usually brushed on, the surface of a concrete floor to harden same. Concrete Primer. A thin liquid compound applied as a first coat to a con- crete surface preparatory to being coated with a more viscous compound. Consistency.* The degree of solidity or fluidity of bituminous materials. Corundum. A crystalline mineral abrasive mined in the United States and ground for use. Cotton Drill. A woven cotton fabric. See Chapter V. Cracked Oil. Petroleum residuum which have been overheated in the proc- ess of manufacture. Cracking. The process of breaking down hydrocarbon molecules by the application of heat. Crude Asphalt. Unrefined asphalt. Crude Oil. Unrefined oil. Crude Tar. Unrefined coal tar. Cut-back Products. Petroleum, or tar-residuums, which have been fluxed each with its own or similar distillate, to a desired consistency. Dampproofing. The process of treating masonry internally or externally, to prevent dampness or moisture from penetrating the masonry. Dead Oils. Heavy oils with a density greater than water distilled from tars. Dehydrated Tars. Crude tar from which all water has been removed. Destructive Distillation. The distillation of organic compounds at suf- ficiently high temperatures so that their identity is destroyed. Dipping Compound. Bituminous compound used for coating pipes and iron tunnel segments to preserve them against rust. Drainage. Provision for the disposition of water in or about a structure. Dust. Earth or other matter in fine, dry particles, so attenuated that they can be raised and carried by air currents. The product of the crusher passing through a fine sieve. Eastern Petroleum. Petroleum found in the eastern part of the United States, principally Pennsylvania. Elaterite. A soft elastic variety of asphalt, resembling rubber, Also an appropriated name of a proprietary waterproofing compound. See Chapter V. Emulsion. A combination of water and oily material made miscible through the action of a saponying agent. Expansion Joint. A separation of the mass of a structure, usually in the form of a joint filled with elastic material, which provides the means for slight movement in the structure. Fabric. A cotton cloth or burlap treated with asphalt or coal-tar pitch. Felt. A soft form of paper sheet composed chiefly of pulp and rags and saturated with coal-tar pitch or asphalt. See Chapter V. Filler. (1) Relatively fine material used to fill the voids in concrete aggre gate. (2) Material used to fill the voids in expansion joints. Fixed Carbon.* The organic matter of the residual coke obtained upon burning hydrocarbon products in a covered vessel in the absence of free oxygen. Flashing. A piece of metal or other waterproof material used to keep water * Adopted by the Am, Soc. for Testing Materials. GLOSSARY OF TERMS USED IN WATERPROOFING 417 from penetrating the joints between a wall or projection, and the roof or other flat part of the structure. See Chapter III. 'Floating. Smoothing, with a trowel, the surface of mortar or concrete. Flux.* Bitumens, generally liquid, used in combination with harder bitu- mens for the purpose of softening the latter. Free Carbon. In tars, organic matter which is insoluble in carbon bisul- phide. See Chapter VII. Fuller's Earth. A fine-grained earthy material of cretaceous formation and resembling clay in appearance. Furring Compound. A compound used to bond plaster to masonry. Gaging Water. Water (in measured quantities) used in mixing mortar or concrete to a required consistency. Gas Black. Soot from natural gas. Gas-drip. A condensate from illuminating gas, present to a greater or less degree in all gas mains and tanks and an effective solvent of most bituminous materials. Gas-house Coal Tar. Coal-tar produced in gas-house retorts in the manu- facture of illuminating gas from bituminous coal. Gasoline. A very volatile distillate of petroleum. See Chapter V. German Wax. A manufactured wax or blend of beeswax and other waxes. Gilsonite. Glance pitch; a pure hard lustrous asphalt found principally in Utah, U. S. A. See Chapter V. Glance Pitch. A very pure solid asphalt or gum asphalt. Grahamite. A pure, solid lusterless asphalt. See Chapter V. Graphite. A soft dark-colored form of carbon with considerable luster. See Chapter V. Gravel. Small stones or pebbles, usually found in natural deposits more or less intermixed with sand, clay, etc., but in which mixture the particles which will not pass a 10-mesh sieve predominate. Grit. Stone chips, slag chips, small pebbles or rounded rock particles graded or ranging in size between | and f inch. Ground Water. That part of rain, hail, or snow, that has percolated through and accumulated in the ground as water chiefly in consequence of an underlying impervious strata. Ground- water Level. The upper surface of ground water. See Chapter I. Grout. A mixture of cement and water or cement sand and water of thinner consistency than mortar. See Chapter V. Grouting. The process of injecting grout or mortar to fill small holes and seams in and around subsurface structures. See Chapter II. Gum. Varnish gum; loosely applied to asphalt. Gum Resins. Resins exuding from cuts in pines. Gumlac. Shellac. Gunite. Trade name for the mortar made and "shot" from the cement gun. See Chapter II. Gutta-percha. A substance consisting of a dried milky juice in many respects similar to caoutchouc, but not elastic; extracted from certain trees in the iropics. Gypsum. Erroneously referred to as plaster of Paris but actually a hydrated calcium sulphate (CaSO 4 , 2H 2 0). * Adopted by the American Reporters on Communication No. 10 at the third International Hoad Congress. 418 APPENDIX IV High Carbon Tars. Tars containing a high percentage of free carbon (between 15 and 25 per cent). Hot Stuff. Washing soda (carbonate of lime) when used to quicken the set- ting time of mortar. Colloquially, also hot molten asphalt, or coal-tar pitch, or mastic made from these. Hydrated Lime. A finely divided white powder, made of ordinary lime to which has been added just sufficient water to insure complete slaking, and leaving the product dry. See Chapter V. Hydrocarbons. Chemical compounds composed of the elements hydrogen and carbon. Hydrolithic. Proprietary trade name applied to the integral system of waterproofing. Hydrolytic. Name commonly applied to materials used in integral water- proofing which tend to prevent the percolation of water through the treated masonry. Hydrex Compound. Trade name for a proprietary asphalt. Imitatite, A black, hard variety of bitumen. Impsomite. A solid bitumen resembling gilsonite, found in Oklahoma, U.S.A. Integral Compound. A material incorporated in mortar or concrete, previous to or during mixing, to waterproof same. See Chapter II. Integral System. The process .of incorporating waterproofing materials in mass mortar or concrete. See Chapter II. Iron (Powdered). Cast iron or pig iron in powder form. Isinglass. The dried swimming bladders of several varieties of fish from which gelatine is extracted. Joint Filler. Any compound used for filling joints between moving parts of steel or masonry (structures) subject to expansion, contraction and vibration. See Chapter IV. Kaolin. A fine clay the purity of which gives it a white color. Lake Pitch. A plastic porous, and about 50 per cent impure asphalt from the asphalt " lake " in the island of Trinidad. Land Pitch. A surface deposit of solid Trinidad Lake asphalt which is tougher and more tenacious than the " lake " asphalt. Land Plaster. Powdered gypsum; also, but incorrectly, used to designate plaster of Paris. Lap Cement. A liquid bituminous compound used for cementing the laps of ready roofing. Larutan Compound. Trade name of a proprietary asphalt. Larutan System. Application of a waterproofing membrane in the form of small squares of asphalt-treated cotton fabric. See Chapter II. Layer. A course or coat made in one application. Lime. A white substance resulting from the burning of limestone. See Chapter V. Linseed Oil. Oil obtained from the seed of flax by pressing. See Chapter V. Lithocarbon. A commercial name for an asphaltic limestone found in Uvalde, Texas, U. S. A. Low Carbon Tars. Tars containing a low percentage of free carbon (between 5 and 15 per cent). Maltha. A natural or artificial asphalt containing sufficient lighter compounds to be liquid. GLOSSARY OF TERMS USED IN WATERPROOFING 419 Malthene. Those portions of asphalt and similar materials soluble in both carbon bisulphide and petrolic ether and not readily volatile at a temperature of 163 deg. Cent. Manjak. A pure, black, lustrous bitumen from Barbadoes, probably related to grahamite. Mastic. A mixture of fine mineral matter and asphalt or coal-tar pitch, applicable in a heated condition. See Chapter V. Mastic Rock. Rock asphalt. Membrane. In waterproofing, a thin layer or layers of bituminous material with or without fabric reinforcement, placed on or about a structure. Membrane System. The system of applying an elastic, membranous water- proofing material. See Chapter II. Metal Primer. A first coat of paint or preserving compound applied to iron or steel. Mineral Naphtha. A volatile petroleum distillate heavier than gasoline. Mineral Oil. Petroleum. Mineral Pitch. A popular name for asphalt. Mineral Rubber. A bitumen of rubbery consistency. Mineral Tar. A liquid bitumen, of a viscid, tarry nature. Mineral Wax. A common term for ozocerite. Minwax. A proprietary asphalt. Mortar. A mixture of sand, cement, or lime (or both) and water mixed to a paste consistency. Naphtha. A volatile petroleum hydrocarbon distillate heavier than gasoline. Naphthalene. A white solid crystalline hydrocarbon, occurring principally in coal tar, of the chemical formula Ci H 8 . Native Bitumens. Bitumens occurring in nature, and for waterproofing purposes, generally as liquids, viscous liquids or solids. Native Paraffin. Ozocerite. Natural Cement. A fine cementing powder made by burning and grinding a cement rock at a somewhat lower heat than Portland cement. See Chapter V. Neponsit Felt. Trade name for a proprietary roofing felt. Neutral Oil. Neutral mineral oil. Oil Asphalts. Artificial oil pitches or asphaltic cements produced as a resid- uum from asphaltic petroleum. Oil Pitches. More or less hard oil asphalts. Oil-gas Tars. Complex hydrocarbon liquids produced by cracking oil vapors at high temperatures in the manufacture of oil gas or carburetted water gas. Oil-tar Pitch. A viscous residuum of any desired consistency from the distillation of oil tars. See Chapter V. Ozocerite. A yellow or brown hydrocarbon, greasy, waxlike substance, occurring in the form of small veins in tertiary rock in Galacia, Austria and Utah, U. S. A. Ozokerite. Same as Ozocerite. Paraffin. Commonly, the same as paraffine; a hard, white, wax-like sub- stance, chemically of the higher hydrocarbons. See Chapter V. Paraffine. A term covering a number of greasy crystalline hydrocarbons of the paraffin series. Paraffin Naphtha. Naphtha from paraffin petroleum. 420 APPENDIX IV Paraffin Oil. A heavy liquid fraction of the manufacture of paraffin from petroleum. See Chapter V. Paraffin Petroleum. Petroleum, the base of which is principally of the paraffin series of hydrocarbons. Paraffin Scale. Solid paraffins in asphalt. See Chapter V. Petrolene. Those portions of asphalt and similar materials which are soluble both in carbon bisulphide and petrolic ether, and which are volatile at 163 deg. Cent, and below. Petroleums. Native mineral oils or fluid native bitumens of variable com- position. Petrolic Ether. A volatile naphtha lighter than gasoline, obtained from petroleum. Pine Oil. A heavy distillate of rosin. Pine Tar. Gum of the pine tree from an incision or by distillation of the wood ; common rosin. Pipe Coating. A bituminous compound applied hot or cold to iron or steel pipes for preservation purposes. Pitch. A sticky resin from pine tar. Semi-solid or solid residues from the distillation of bitumen; usually applied to residue obtained from tar. Short, for coal-tar pitch. Pitch (Hard). Pitch showing a penetration of not more than ten. Pitch (Soft). Pitch showing a penetration of more than ten. Pitch (Straight-run).* A pitch run in the initial process of distillation, to the consistency desired without Subsequent fluxing. Plaster Bond. Name of various bituminous compounds used for bonding plaster to masonry walls, and which also serve as dampproofing mediums. Plaster of Paris. A hydraulic cement; a chalky powder resulting from the calcination of pure gypsum (a hydrated calcium sulphate) at a temperature between 250 and 400 deg. Fahr. losing thereby three-quarters of its water of combination. Plastic Roofing. A plastic (when warm) roofing compound applied 'with a trowel, composed of some fine or fibrous inert substance mixed with tar or other bitumen. Plastic Slate. A mixture of coal tar and powdered slate. Portland Cement. A fine cementing powder made by carefully burning and grinding a cement rock or an artificial mixture of limestone and clay. See Chap- ter V. Primer. A first coat applied to masonry preparatory to receiving the suc- cessive coats of material for waterproofing or dampproofing purposes. Puzzolan Cement. A very fine cementing powder made by mechanically mixing and powdering slaked lime and volcanic ash or slag. Pyrobitumens. Mineral organic substances forming bitumens upon being subjected to destructive distillation. Pyrogenetic. That which originates from the action of heat. Quasi-colloidal Bodies. Like, or nearly colloidal, particles. Quasi-soap. Like, or as if it were, soap. Red Rope Paper. A red variety of building paper partly composed of rope waste. Reduced Oils. Reduced petroleums. * Proposed by the Committee on Standard Test? for Road Materials (Committee D-4) of the American Society for Testing Materials. GLOSSARY OF TERMS USED IN WATERPROOFING 421 Reduced Petroleums. Residual oils from crude petroleum after removal of water and some volatile oils, but with the base chemically unaltered. Refined Asphalt. Bitumen after it has been freed wholly or in part from its impurities. Refined Tar. A tar freed from water by evaporation or distillation which is continued until the residue is of desired consistency or a product produced by fluxing tar residium with tar distillate. Residual Oils. Residual petroleums. Residual ^Petroleum. Viscous residue from the distillation of crude petroleum with all the burning oils removed. Residual Tars. Tar pitch or viscous residue from the distillation of crude tar with all the light oils removed. Resin. A dried and hardened pitch from pine and similar trees. See Chap- ter V. Rock Asphalt. A solid asphalt obtained from a naturally impregnated limestone or sandstone, also the naturally impregnated stone. Roofing Cement. A plastic mixture of paint skins, coal tar, pine tar and soya oil commonly used to seal flashing joints. Roofing Gravel. Approximately f-inch gravel. Roofing Slag. Slag crushed to the size ranging between \ and Hnch. Rosin. Pine pitch with the chemical formula C 4 4H 62 O4. See Chapter V. Salammoniac. Ammonium chloride; a white crystalline soluble substance (NH 4 C1). See Chapter V. Sand. Finely divided rock detritus the particles of which will pass a 10-mesh and be retained on a 200-mesh screen. Sand Cement. A very fine cementing powder made by grinding together a mechanical mixture of Portland cement and pure, clean sand. Semi-asphaltic Oils. Semi-asphaltic petroleum. Semi-asphaltic Petroleum. Petroleum of a semi-asphaltic base. Sheet Mastic. Bituminous mastic in the form of a sheet used for paving and waterproofing purposes. See Chapter II. " Short." A term applied to materials possessing little ductility. Soap. A metallic salt of fatty acid. See Chapter V. Soda Ash. Washing soda (carbonate of lime) of the chemical formula (Na 2 C0 3 , 10H a O). Soluble Glass. Water glass. Stearate. A salt of stearic acid. See Chapter V. Stearic Acid. A derivative product of the more solid fats of the animal kingdom. (CH 3 (CH 2 ) 16 COOH). See Chapter V. Stearin. The chief ingredient of suet and tallow. See Chapter V. Stearin Pitch. A black, elastic, non-brittle, animal by-product obtained from stearic acid in the manufacture of candles. See Chapter V. Subway Asphalt. Common name for a particular quality of asphalt used in waterproofing the New York Subways. See Chapter VIII. Subway Pitch. Common name for a straight-run coal-tar pitch used in waterproofing subways in New York City. See Chapter VIII . Suet. The hard and semi-fusible fat about the kidneys and loins of animals. See Chapter V. Surface Coating. Any compound applied to a masonry surface for damp- proofing or waterproofing purposes. 422 APPENDIX IV Sylvester Process. The process of applying alternate coats of soap and alum solutions for waterproofing and dampproofing purposes. See Chapter II. Tar Pitches. Semi-solid or solid residual tars. Tar. Bitumen which yields pitch upon fractional distillation and which is produced as a distillate by the destructive distillation of bitumens, pyrobitumens, or organic material. See Chapter V. Texene. A trade name for a turpentine substitute. Torpedo Gravel. A coarse hard grit. Trinidad Asphalt. A solid or semi-solid asphalt, brown to black in color, porous and about 50 per cent impure, obtained from the island of Trinidad. Turrellite. A black, hard variety of bitumen. Vintaite. Gilsonite. Varnish Gum. Any resinous substance excluding rosin. A term used to designate, but incorrectly so, asphalt and coal tar when used in proprietary water- proofing compounds. Viscosity. The measure of the resistance to flow of a bituminous material, usually stated as the time of flow of a given quantity of the material through a given orifice. Volatile. Applied to those fractions of bituminous materials which will evaporate at climatic temperatures. Water Absorbent. A property of a floor-hardening or waterproofing material which makes it readily miscible with water. Water Glass. Sodium silicate (Na.Si,O 9 ) or alkaline silicates soluble in water. Water Repellent. A property of a waterproofing material which hinders or prevents its miscibility with water. Water Table. Loosely applied to ground -water level. Waterproofing. The process of treating masonry to exclude or prevent the percolation of moisture or water through it. Water-gas Tar. A liquid hydrocarbon produced by cracking oil vapors in the manufacture of carburetted water-gas. See Chapter V. Wurtzelite. A black, hard variety of bitumen. APPENDIX V REFERENCES The following reference literature is arranged only approximately according to the caption topics. Most of this literature was consulted in the preparation of this book, acknowledgments being made in foot-notes. The author is gratified to note the increased interest manifested in waterproofing engineering since the commencement of this book, four years ago, and the broader viewpoint assumed by writers of modern literature on the art of waterproofing. Asphalt and Tar. Richardson's Modern Asphalt Pavement. Bituminous Road and Paving Materials, by Hubbard. The Art of Roadmaking, by Harwood Frost. Effect of Illuminating Gas on Asphalt Pavements, Eng. News, Mar. 4, 19L K , Vol. 73, No. 9, p. 441. Waterproofing, by Boorman, Proceedings National Association of Cement Users, 1909. Coke-oven Tars of the United States. Office of Public Roads, Circular No. 97, U. S. Dept. Agriculture, 1912. Concrete in General. Concrete, Plain and Reinforced, by Taylor and Thompson. Concrete, Plain and Reinforced, by Homer A. Reid. Reinforced Concrete, by Buel and Hill. Cairn's " Cement and Concrete." Reinforced Concrete, by Marsh. Oil-mixed Portland Cement Concrete, Bulletin No. 230, Office of Public Roads, U. S. Dept. of Agriculture, 1915. Concrete in Sea Water. The effect of SO 3 in Portland Cement. Proceedings of Association of German Portland Cement Manufacturers, 1911. " Action of Sea Water on Hydraulic Binding Media," by Lombard and Deforge, International Association for Testing Materials Proceedings, 1912. " Action of Sea Water on Reinforced Concrete," by de Blocq van Kuffeler, International Association for Testing Materials Proceedings, 1912. " The Different Iron and Slag Cements," Engineering News, September 7, 1911, Vol. 66, No. 10, Editorial. " Ferrite Cement and Ferro Portland Cement," by E. C. Eckel, Engineering News, Aug. 3, 1911, Vol. 66, No. 5. "The State of Preservation of Test Blocks," by W. Czarnowski. Inter- national Association for Testing Materials, 1912. 423 424 APPENDIX V " Cement in Sea Water," by A. Poulson. International Association for Test- ing Materials, 1909. " Official German Recognition of the Harmless Nature of a Slag Addition to Portland Cement Clinker." Engineering News, September 7, 1911. " Experiments on the Decomposition of Mortars by Sulphate Waters," by G. A. Bied. International Association for Testing Materials, 1909. " Some Observations on the Disintegration of Cinder Concrete," by George Borrowman. Journal of Industrial and Engineering Chemistry, June, 1912. " Disintegration of Fresh Cement Floor Surfaces," by Alfred H. White, American Society for Testing Materials, Vol. 9. Relative Effects of Frost and Sulphate of Soda Effloresence Tests on Build- ing Stones. Transactions of the American Society of Civil Engineers, Vol. 33, 1895. Action of the Salts in Alkali Water and Sea Water on Cements. U S. Bureau of Standards, Bulletin No. 12, Nov., 1912. Action of Sea-water on Mortar. Cement Age, March, 1907. Destruction of Cement Mortar and Concrete by Alkali at Great Falls, Mont. Eng. Cont., June 24, 1908. Durability of Stucco and Plaster Construction. U. S. Bureau of Standards Bulletin No. 70, Jan., 1917. What is the Trouble with Concrete in Sea Water? Engineering News-Record, Vol. 79, No. 12, page 532. Dampproofing. The prevention of Dampness in Houses, by A. F. Keim. Electrolysis. Electrolysis in Concrete; Tech. Paper No. 18, Bureau of Standards, U. S. Dept, of Commerce, 1913. Surface Insulation of Pipes as a Means of Preventing Electrolysis. Tech. Paper No. 15, Bureau of Standards, U. S. Dept. of Commerce, 1914. Special Studies in Electrolysis Mitigation, Tech. Paper No. 32, Bureau of Standards, U. S. Dept. of Commerce 19 Engineering Structures. Waterproofing An Engineering Problem, by Myron H. Lewis. Proc. Engrs. Club of Phila.,. Vol. 25, page 339, Oct., 1908. Waterproofing, Progress Report of Special Committee on Concrete and Rein- forced Concrete. Trans. Am. Soc. C. E., Vol. 66, page 444, March, 1910. Waterproofing Cement Mortars and Concretes, by H. Wiederhold. Proc. Natl. Assoc. Cement Users, Vol. 3, page 228, 1907. Waterproofing Cement Mortars and Concretes, by Edward W. De Knight. Proc. Natl. Assoc. Cement Users, Vol. 3, page 238, 1907. Waterproofing Concrete and Masonry, by Edward W. De Knight, Eng. News, Vol. 57, page 187, Feb. 14, 1907. Waterproofing Cement Structures, by James L. Davis, Proc. Natl. Assoc. Cement Users, Vol. 4, page 323, 1908. Waterproofing of Concrete Structures, pages 344-74. Hand-book for Cement and Concrete Users, by Lewis and Chandler. Making Concrete Waterproof, by Prof. I. O. Baker, Eng. News, Vol. 62, page 390, Oct. 7, 1909. REFERENCES 425 Waterproofing of Engineering Structures, by W. H. Finley, Journal Western Society of Engineers, June, 1912. The Waterproofing of Solid Steel Floor R.R. Bridges, Am. Society Civil Engrs., Vol. 40, No. 10, Dec., 1914. Report of Committee VIII on Masonry, Proceedings Am. Railway Engineer- ing Association, Vol. 15, page 569, March, 1914. Review of Various Experiences in Waterproofing. " Concrete," April, 1916. " Engineering Geology," by Heinrich Reis and Thomas L. Watson. The Manufacture of Coke in the United States. U. S. Geologic Survey Bulletin, Dept. of Interior, 1913. , Formulas and Recipes. Henley's 20th Century Book of Formulas and Recipes. " Paint Making and Color Grinding," by Charles S. Uebele. General Literature on Waterproofing. " Masonry Construction," by Ira O. Baker. " Building Construction," by Prof. Henry Adams. Merriman's " Civil Engineer's Pocketbook." Subways and Tunnels of New York, by Gilbert, Wightman and Saunders. ^ Panama Canal Waterproofing, Engineering News, Vol. 73, No. 5, page 215, Feb. 4, 1915. Treatise on Arches, by Scheffler. + Impermeable Water Tanks, Eng. News, Mar. 18, 1914, Vol. 71. Grouting. " Lining Rondout Pressure Tunnel," New York, Engineering Record, Dec. 30, 1911, page 772. Grouting Big Savage Tunnel, Using Air, Eng. Rec.. page 728, Dec. 23, 1911. Olive Bridge Dam, New York, Eng. Rec., page 385, April 8, 1911. Rondout Pressure Tunnel, New York, Eng. Rec., page 315, Sept, 17, 1910. Grouting Arches, Hamburg, Germany, Eng. Rec., page 258, Sept. 3, 1910. French Methods and Machines, Eng. Rec., page 495, Oct. 30, 1909. Foundations in England, Eng. Rec., page 474, April 4, 1908. Stopping Leaks, Cincinnati Water Works, Eng. Rec., page 224, Mar. 4, 1905. " Grouting a Water-bearing Rock Seam on Catskill Aqueduct," Eng. News, Vol. 67, No. 6, page 278, Feb. 8, 1912. Test of Watertightness of Concrete Tunnel Lining under High Head, Eng. News, Vol. 66 ; No. 24, page 710, Dec. 14, 1911. Mixing and Conveying Concrete by Compressed Air, Eng. News, Vol. 66, No. 6, page 173, Aug. 10, 1911. Rondout Pressure Tunnel, New York, Eng. News, Vol. 65, No. 22, page 654, Junel, 1911. Lining and Grouting a French Railway Tunnel in Water-bearing Material, Eng. News, Vol. 62, page 580, Nov. 25, 1909. Pumping of Cement Grout into Masonry on the Metropolitan Railway, Paris, Eng. News, Vol. 62, page 581, Nov. 25, 1909. Grouting a Leaky Tunnel on the Paris, Lyons and Mediterranean Railway, Eng. News, Vol. 56, No. 15, page 374, Oct. I'l, 1906. " Catskill Aqueduct," by Lazarus White. 426 APPENDIX V Inspection. Inspection of Waterproofing for Concrete Work, by Jerome Cochran, Engr. and Contr., Vol. 37, pages 370 and 404, April 3 and 10 3 1912. Joints. Effect of Oil on Cement Mortar, Eng. News, July 4, 1907, Vol. 58, No. 1. Efficiency of Cement Joints in Joining Old Concrete to New, Eng. News, Dec. 12, 1907, Vol. 58, No. 24. Strength of Concrete Joints, Proceedings of Engineer's Society of Western Penn., Dec., 1908. Lime, Hydrated Lime and Clay. " Hydrated Lime," by E. W. Lazell, Ph. D. (1915). The Colloid Matter of Clay and its Measurement. Bulletin No. 388, U. S. Geol. Survey, Dept. of Interior, 1909. Lime: Its Properties and Uses; Circular No. 30, Bureau of Standards, U. S. Dept, of Commerce, 1911. Metal Sheetings. " Harlem River Crossing of the Lexington Ave. Subway." New York Muni- cipal Eng. Journal, Vol. 1, No. 6, Dec., 1915. Methods of Waterproofing. Methods of Waterproofing Concrete, by Richard H. Gaines, Eng. News, Vol. 58, No. 13, page 344, Sept. 26, 1907. Current Methods of Waterproofing Concrete-covered Bridge Floors, Eng. Rec., Vol. 58, page 488, Oct. 31, 1908. Waterproofing the New York Subways, Railway Review, Vol. 58, No. 11, March, 1916. Subaqueous Highway Tunnels, American Society C. E., Vol. 4, No. 9, Nov.> 1914. Roofing. Inspector's Pocket Book, by A. T. Byrne. Building Mechanics' Ready Reference, by H. G. Richey. Sand and Cement. Standard Sand for Cement Work, Eng. Rec., July 20, 1907. Sands: Their Relation to Mortar and Concrete, Cement Age, July, 1908. A Sand Specification and its Specific Application, Proc. of the Amer. Soc. for Testing Materials, Vol. 10, 1910. The Cement Industry in the United States, U. S. Geol. Survey, Dept. of Interior, Bulletin for 1910. Brown's " Hand Book for Cement Users." Specifications. Specifications Covering Methods of Waterproofing Engineering Structures by Joseph N. O'Brien, Eng. Contr., Vol. 34, page 26, July 13, 1910. Specifications for Obtaining Dampproof and Waterproof Substructures, Eng. Contr., Vol. 34, page 239, 1910. Specifications and Instructions for Waterproofing Metal and Masonry Structures, by W. H. Finley, Eng. Contr., Vol. 30, page 289, Nov. 4, 1908, Specifications for Waterproofing Concrete Work, by W. H. 'Finley, Proc, Natl. Assoc. Cement Users, Vol. 1, page .35, 1905. REFERENCES 427 Specifications for Waterproofing Concrete Bridges Chicago and North- western Railway, Proc. Natl. Assoc. Cement Users, Vol. 1, 1905. Specifications for Waterproofing Bridges in the District of Columbia, Proc. Natl. Assoc. Cement Users, Vol. 5, page 146, 1909. Specifications for Waterproofing a Pumping Chamber in Ground under External Head of Water, Proc. Natl. Assoc. Cement Users, Vol. 5, 1909. Specifications for Waterproofing New York Rapid Transit Subway, Proc. Natl. Assoc. Cement Users, Vol. 1909, page 237. Specifications for Waterproofing Solid Steel-floor R.R. Bridges, Eng. Cont., Sept., 1915. Tests. Methods for Testing Coal tar, etc., by S. R. Church, Journal of Industrial and Engineering Chemistry, Vol. 5, No. 3, 1913. Specific Gravity, Its Determination, etc., by J. M. Weiss, Journal of Industrial and Engineering Chemistry, Vol. 7, No. 1, 1915. The Permeability of Concrete under High Water Pressure, Eng. News, Vol. 47, No. 26, page 517, June, 1902. Paraffin Test as Applied to Bituminous Road Compounds, Eng. News, July 8, 1911, Vol. 65, page 680. Methods for the Examination of Bituminous Road Materials, Bulletin No. 314, U. S. Dept. of Agriculture, 1915. Permeability Tests on Gravel Concrete, Eng. Rec., Sept. 26, 1914. Permeability Tests of Concrete, Eng. Rec., Jan. 21, 1911. Test of Concrete for Impermeability, Eng. Rec., May 28, 1910. Impermeability Tests on Concrete, Eng. News, Nov. 7, 1912. Investigation of Impermeable Concrete, Eng. Contr., Feb. 26, 1908. Progress Report on Materials for Road Construction and on Standards for Their Tests and Use. Amer. Soc. C. E., Vol. 40, No. 10, Dec., 1914. The Testing of Materials. Circular No. 45, U. S. Bureau of Standards, Dept. of Commerce, 1913. Some Practical and Technical Tests on Waterproofing Materials, N. Y. Municipal Engineers' Journal, Sept., 1917. Waterproofing Fabrics. Manufacture, Test and Use of Waterproofing Fabric, Eng. News, Vol. 72, Sept. 24, 1914. The Waterproofing of Fabrics by Mierzinski. Linen, Jute and Hemp Industries; Special Agents Series No. 74, U. S. Dept. of Commerce, 1913. Waterproofing Instructions. Instructions for Waterproofing Concrete Surfaces, by W. J. Douglas, Eng. News, Vol. 56, No. 25, page 645, Dec. 20, 1906. Directions for the Application of Waterproof Cement Coatings, Eng. News, Vol. 57, Jan., 1907, page 247. Suggestions for Waterproofing Subways, Public Service Record, Vol. 3, No. 7, July, 1916 (Publication of Public Service Commission for 1st District, State of New York). Popular Handbook for Cement and Concrete Users, by M. H. Lewis, C. E. Waterproofing Materials. Materials of Construction, by Thurston. INDEX Absorption, Defined, 7 of Concrete, 4, 229, 230 - Raw Fabrics, 256, 257 Felts, 256, 257 Stone, 4 Treated Felts, 256, 257 Fabrics, 256,257 Abutments, Protection of, 31 Acid Treatment, 21 Sludge Defined, 413 Acids, Effect of, 29 in Ground Water, 3 Actinolite, Use of, 111 Adhesion between Laps, 46 Adhesives, 320 Aggregate for Mastic, 63 Defined, 413 Scientific Proportioning, 77 Air Compressor, Use of, 87 - Pockets, 23, 47 Temperature, 28 Akeley, Mr. C. F., 19 Albertite Defined, 413 Alcohol, Specific Gravity, 387 Alkalies, Effect of, 29 Alkaline, 3 Alum, 26, 145, 147, 374 Defined, 413 Nature of, 147 Solution, 28 Use of, 197 Alumina, 9 Aluminum Sulphate, 28 Stearate, 66 Am. Ry. Engrs. Assn., 117, 129 Soc. T. M. Report, 408 Anthracene Defined, 413 Arbitrary Selection, 78 Arches, 32 Architect's Duty, 25 Armor Coat, 58 Asbestine Defined, 413 Asbestos, 23, 31, 374 Covered Roofing, 121 - Covered Sheet Iron, 120, 146 - Defined, 413 Felt, Application of, 111 Defined, 153, 413 - Saturated, 146 - Use of, 45, 153 Fibre, Use of, 63 - Filler, Effect of, 238, 240 - Nature of, 153 Shingles, Application of, 11, 101, 102, 103 Manufacture of, 102 Shredded, 32 Specific Gravity, 387 - Use of, 56, 153 Ash Water Glass Defined, 413 Asphalt, 32, 145, 146, 147, 374 - Blown, Use of, 141 Cement Defined, 413 Characteristics of, 51 Coefficient of Expansion, 387 Containing Pitch, 240 Consistency of, 49 - Cutter, 178, 179 - Defined, 413 Ductility of, 240 Effect of Overheating, 49 Heating Kettle, 175, 174 of, 49 Joint Filler, 142 - Mastic Defined, 413 Nature of, 154 Odor of, 49 Pavement Defined, 413 Preference for, 52 430 INDEX Asphalt, Produced, 51 Publications on, 423 Putty Defined, 413 Quality of, 51 Smoother, 177 Specific Gravity, 387 - Use of, 17, 31, 32, 154 Versus Coal-tar Pitch, 51 Asphaltenes Defined, 413 Asphaltic Coal, 414 Concrete, 414 - Defined, 413 Limestone Defined, 414 Oils Defined, 414 Petroleum Defined, 414 Sandstone Defined, 414 Asphaltite Defined, 414 Asphaltum Defined, 414 B Backfill, 13, 39, 40 Bacterial Decomposition, 8 Bakelite, 146, 147, 414 - Use of, 154 Bank-run Gravel, 78, 414 Barrels, Cost of, 373 Barret Specification Felt, 414 Basement Waterproofed, 365 Bats, Use of, 56 Battens, Use of, 114 Baume Table, 381, 382, 383, 384, 385 Gravity, 414 Beeswax Specific Gravity, 387 Coefficient of Expansion, 287 Benzene Defined, 414 Benzine, 145, 147 Cost of, 374 - Defined, 414 - Use of, 155 Benzol, Cost of, 374 Defined, 414 - Use of, 155 Bergen Hill Tunnels, 335, 336 Bermudez Asphalt Defined, 414 Binder, 32, 414 Bitumen, Artificial Defined, 413 Defined, 414 for Mastic, 62 Ready Roofing, 112 Transportation, 50 Bituminous Binder, 34 Blanket, 31 Cement Defined, 414 Coat Applied, 24' Compound, Use of, 16, 29, 46, 146 - Defined, 414 Emulsion Defined, 414 - Enamels, 29 - Fillers, 142 Mastic, 29, 52 - Paint, 18, 29, 142, 147, 155, 414 - Paste, 29, 31 - Putty Defined, 414 Rock Defined, 414 Bleeders, Use of, 58 Blistering, 20, 26 Block Tin, Use of, 108 Blow H61es, 34 Blown Asphalt, Use of, 143, 414 Oil Defined, 414 Petroleum Defined, 414 Board Sheathing, 308 Bond, Effect of Surface, 249 Bonding Fabrics, 47 - Day's Work, 70 Boston Tunnels, 337, 338 Brick, Absorption of, 4 Applied, 56 - Bond, 249 Compression of, 249, 250 Cost of, 374 Courses, 57 Function of, 56 - Heating Methods, 65, 66, 183, 373 - in Mastic, 52, 53, 54, 56, 57, 63, 146, 355 - Parapet, 118 Protective Medium, 37 Quality of, 61, 63 Roof Domes, 92 Sewers, 20 Soot Covered, 65 Specific Gravity, 4, 387 - Walls, 58 Bridge Floors, 67 Waterproofed, 53 Bronze Plate Roofs, 92 Brooklyn Railroad Viaducts, 34 Broom, Cost of, 373 Bubbles in Mastic, 62 INDEX 431 Buckets, Use of, 50 Building Foundations, 32 Paper Denned, 414 Built-up Roofs, 92, 108, 308, 310, 415 Membrane, 31, 45 Bulge in Mastic, 61 Burlap, Use of, 47, 155, 375 Denned, 415 - Membrane, Weight of, 388 Butt Joints, 43 Byerlite Denned, 415 Caffall Process Defined, 415 Caisson Cross-section, 292 Calcium Compounds, 9, 66, 75, 147, 148, 415 Minerals, 146, 147 Oxide, 8 Sulphate, 8 Calking Joints, 144 - Tunnels, 366 Caoutchouc, Specific Gravity, 387 Defined, 415 Capillary Passageways, 7, 19, 47 Carbenes Defined, 415 Carbolineum, 93 Carbon Bisulphide, Defined, 415 Disulphide, Defined, 415 Tetrachloride, Defined, 415 Carborundum, 231, 415 Casein, Defined, 415 - Use of, 148 Cast-iron Tunnel Segments, 363 Use of, 146, 147, 156 Cast Steel, 146 Castor Oil, Specific Gravity, 387 Catskill Aqueduct, 87, 359 Caustic Potash, 145, 147, 148, 374 Cedar, Specific Gravity, 387 Cells in Concrete, 7 Cement, 145, 375, 415 Additions to, 409 Benzine Resisting, 318 Coating, 147 Coefficient of Expansion, 387 Effect of Alkali, 405, 407 Fineness, 76, 77 - Water, 403, 407 Wetting, 77 Cement, Excess, 77 Floor Defined, 415 - for Mastic, 318 Grouting, 85 -Gun Operation, 19, 20, 184, 185, 186, 373 Hydration of, 77 - Mortar, Use of, 156, 16 Petroleum Resisting, 318 Publications on, 426 Quick-setting, 85 Specific Gravity, 387 - Tiles, 97 Cerasin Defined, 415 Cerite Defined, 415 Charcoal, 29 Cheese, Use of, 144 Chemical Acting Materials, 146, 147 Chimneys, Flashing for, 117 China Clay, 72, 415 - Wood Oil, Defined, 415 Specific Gravity, 387 - Use of, 31, 143, 148 Chipping of Surface, 21 Chloride of Lime, 74 Choctow Defined, 415 Cinder, Concrete Absorption, 4 Specific Gravity, 4 Cisterns, 24 Civilization, Measure of, 2 Clay, 66, 75, 415 - Oil-joint Filler, 142 Publications on, 426 Specific Gravity, 387 - Tiles, 95, 96 -Use of, 26, 71, 72,91, 156 Clay-cement Waterproofing, 365 Cleats, Use of, 108 Climate, Consideration of, 31 Clinker, 72 Coal Tar Defined, 415 - Pit Waterproofed, 366 Coal-tar Pitch, 32, 146, 147, 374 Characteristics of, 49, 51 Defined, 415 Joint, Filler, 142 Overheating, 49 Produced, 51 Versus Asphalt, 51 Products, 31, 75 432 INDEX Coal-tar Pitch, Use of, 31, 49, 157, 164 Coat Defined, 415 Coating Continuous, 30 on Felts, 252, 253 Fabrics, 252, 253 Coatings, Application of, 21 Applied by Brush, 19 Machine, 19 Trowel, 19 Continuity of, 19 Coefficient of Expansion, 12, 124, 125 of Materials, 387 Coke Oven Tar Defined, 415 Coking of Bitumen, 49 Colloidal Clay, 71, 146, 147 Matter, 75, 415 Colophony Defined, 415 Column Bases Waterproofed, 11 Composite Roofing, 120, 122 Composition Roofing, 92, 108 Compounds, Effect of Earth, 29 ^Backfill, 29 Compressed Asphalt Defined, 416 Compression of Brick, 249 Mastic, 249 Membrane, 260 Mortar, 249 Concrete, 374 Absorption of, 3, 4 Additions to, 409 Age, 2 Atomizer, 89, 90 Average Weight of, 4 Coefficient of Expansion, 387 Consistencies, 78 Cutoffs for, 137 Effect of Alkali, 405, 407 Floor Hardener, 319, 416 Hand Mixed, 77 in Sea Water, 403, 406, 407 Machine Mixed, 77 Parapet, 118 Pipe Joints, 137, 138 Reinforcement, 82 Porosity of, 7, 77 Primer Defined, 416 Protective Coat, 37 Publications on, 423 Railroad Details, 343 Reinforcement, 125 Concrete Roof Slab, 310 - Roofs, 123 Safeguarded, 9 Specific Gravity, 4, 387 Standpipe, 331 Tampers, 181, 182 Tank Waterproofed, 356 - Tile, 95, 96, 97, 98, 99, 100, 229, 230 Time of Mixing, 99 Universal Material, 3 Conglomerate, Absorption of, 4 Specific Gravity, 4 Consistency Defined, 415 Construction Joints, 14, 38, 128 Efflorescence, 14 Shaft, 83 Contractors, Graded, 370 Copal Gum, ,72 Coping, 117 Copper Bulb Joint, 134 - Cutoffs, 134 Sheeting, 105, 108 Specific Gravity, 387, 393 V- Joints, 131 Cord Wood, 373 Cores, 48 - Fabric Roll, 182 - Felt Roll, 182 - Illustrated, 183 Corrosion, 2 of Metallic Powders, 27 Corrugated Roofing, 121 Sheet Iron, 120, 393 Corundum Defined, 415 Cost Data, 371, 372 - Low First, 145 of Materials, 374 Implements, 373 Labor, 372 Tin, 378 Waterproofing Applied, 376, 377 Cotton, Drill, Use of, 34, 46, 48, 157, 375, 416 Fabric, 45, 46, 47 Membrane, 388 - Roofing, 111, 120 Cove Finish, 53 Cracked Oil Defined, 416 Cracking, 20, 416 Cracks, Prevention of, 125 INDEX 433 Cracks, Cause of, 67 Creosote, 93 Oil, Application of, 31 Crude Tar De ined, 416 Asphalt Defined, 416 Oil Defined, 416 Crumbling Palisades, 8 Cube in Air Method, 198 Water Method, 198 Curing, 26 Cut-back Pitch, 111 Products Defined, 416 Cutoff, Use of, 134 Wall, 17, 83, 85 Cutters, 178, 373 Cypress Shingles, 92 D Dam, Ashokan, Cutoff, 358 Waterproofed, 325 Dampproof, 13, 16 Dampproofing Compounds, 29, 314 Defined, 416 Publications, 424 Walls, 16, 316 Davit Attachment, 174 Day's Work Joint, 128 Plane, 68 Dead Oil Defined, 416 Dehydrated Tars, Defined, 416 Dense Concrete, 77, 78, 80 Density, 3 Effect of, 67 Factors, 76 Depressions in Surface, 33 Design Details, 81 Destructive Distillation Defined, 416 Development of Waterproofing, 1 Dike Form Joint, 339 Dipper, 167, 177, 373 Dipping Compound, 416 Disintegrating Effect, 2, 8, 26 Drain Pipes, 6 Drainage, 5, 6, 134 Defined, 416 System, 33, 349 Drop Point Apparatus, 207, 208 Dry Spots, 34 Ply, 33, 54, 58 Surface, 26, 33 Drying, 26 Oven, 214 Dual Subways in N. Y. C., 54 Ductility of Asphalt, 240 . Relation to Temperature, 246 Dust Defined, 416 Dwellings, Concrete, 2 E Earth Excavation, 58 East View Tunnels, 331 Eastern Petroleum Defined, 416 Efflorescence, 6, 12, 14 Egyptians Practice Waterproofing, 1 Elastic Membrane, 31, 45 Elaterite, Use of, 145, 147, 157 - Defined, 416 Electric Oven, 213, 373 Resistance, 10 Electricity, Effect of, 9 Electrolysis, 4, 9, 10 Publications, 424 Emulsion Defined, 416 Enamels, 145 Engineering and Contracting, 8, 369 Engineering News, 325, 328, 334, 337 Engineering News-Record, 85, 322 Engineering Record, 337, 352 Equipment for Grouting, 86 Estimates, 368, 369 Evaporating Oven, 214 Examples of Membrane Application, 331 Grouting, 357 Integral Application, 356 Mastic Application, 353 Self-densification, 356 Special Waterproofing, 360 Excavating Foundations, 29 Excess Cement, 26, 70 Expansion Joint, Basic Types, 129 - Cutoff, 136 Defined, 416 Design of, 126 Drain Pipe, 138 Effect of, 12 Fillers, 129 Function of, 124 Illustrated, 130 Properties of, 124, 128 Reinforced, 135 434 INDEX Expansion Joint, Sliding, 138, 139 Spacing of, 126 Waterproofed, 135 Expansive Force of Freezing Water, 7 Concrete, 7 Exterior Applications, 29 External Cutoffs, 134, 139 Treatments, 410, 411, 412 Exudation of Lime Salts, 15 Fabrics, 34, 48, 146, 374, 416 Membrane, 52 Fats, Specific Gravity, 387 Fattening Materials, 146 Feldspar, 66, 71 Felt Joint Protection, 132 Felts, 32, 34, 46, 47, 48, 146, 158 Cost of, 374 Defined, 416 Flashing, 119 Membrane, 31, 52, 388 Roofing, 92, 108, 109 Weight of, 379 Ferrules, Use of, 349 Fillers, Analysis of, 72, 73 Defined, 416 Use of, 62, 66, 72 Film, Continuous, 30 Finial Tiles, 98, 99 Finishing Coat Applied, 22 Fire in Kettles, 50 Wall Flashing, 16 Fireproof Liquids, 93 Fireproofing, 16 Fish-oil, Use of, 72, 75 Fissured Rock Solidified, 83 Fixed Carbon Defined, 416 Flashing, 116, 117, 118, 416 Flat Roof, 92, 110 Seam Roofing, 106, 108 Floating Defined, 417 Mortar Surface, 20 Floats, 182, 183 Flood Water, 5 Floor Joint Filler, 144 Hardener, 27, 231, 232, 233 - Treatments, 319 Waterproofing, 53 Flow Point Apparatus, 209 Flux Defined, 417 Foreign Substances, Addition of, 67, 409 Foreman of Waterproofers, 372 Forms for Post Holes, 56 Armor Coat, 59 Bracing, 60 Filling, 59, 61 Setting up, 59 Formulas, Special, 313 Publications on, 425 Foundation of Pyramids, 1 -Walls, 29 Frea's Electric Oven, 213 Free Carbon, 214, 215, 216 - Defined, 417 Freezing Effect of Water, 2, 7 Fuel Material, 29, 50 Fullers' Earth, 80, 417 Functional Roofing, 92, 120, 123 Fundamental Waterproofing Require- ments, 33 Fumes, 49 Furring Compounds, 417 Gable Roofs, 92 Gas Black, 417 Drip, 36, 417 - House Coal-tar, 417 - Main, Effect of Leaks, 36 - Oven, 214 Gaskets, Use of, 129 Gasoline, 31, 57, 147, 158, 374, 417 - Torch, 33, 178 Gauging Water, 417 Gelatinous Compound, 75, 146 General Electric Method, 198, 205, 206 German Wax Defined, 417 Gilsonite, Defined, 413, 417 - Use of, 143, 147, 159. 374 Glance Pitch Defined, 417 Glass Roofing, 120, 122 Specific Gravity, 387 Glossary of Terms, 413 Gooch Crucible, 193 Government Publications, 313 Grading, Laws of, 67, 80 Grahamite, Defined, 417 - Use of, 147, 159 Granite, Absorption, 4 INDEX 435 Granite, Specific Gravity, 4, 387 Granolithic Finish, 20, 24 Graphite, Defined, 417 Specific Gravity, 387 - Use of, 146, 147, 159, 375 Gravel Concrete, 78 Absorption, 4 - Defined, 417 - Heater, 175, 181 Roof Covering, 109 Specific Gravity, 4, 147, 375 - Use of, 159 Grit Defined, 417 Ground Water, Depth of, 2, 5, 52 - Defined, 417 Effect on Concrete, 5 - Fabric, 255 Grout, 82, 145, 147, 417 Grouting Machine, 186, 187, 373 Materials, 146 - Process, 17, 82, 84, 87.. 88, 359, 417 Publications, 425 Gum Defined, 417 Gumlac Defined, 417 Gunite Defined, 417 Gutta Percha, Specific Gravity, 387 - Defined, 417 Gutters, 118, 120 Gypsum, Specific Gravity, 387 - Defined, 417 H Hail, 5 Hair Checks, 26 Hard Soap, 28 Harlem River Tunnels, 360, 361 Harris, Mr. Robert L., 83 Headers, 61 Heat, Effect on Pitch, 236 - Linseed Oil, 236 Heating Kettles, 50, 170, 171, 173 - Pan, 178, 180 High Carbon Tars, 418 Horizontal Joints, 128 Hot Stuff Defined, 128 Hudson-Manhattan Tunnels, 330, 365 Hydrated Lime, 66, 67, 146, 147, 375, 426 Composition, 71, 418 Proportion, 70 Hydrated Lime, Specific Gravity, 7, 83 - Use of, 69, 148 Magnesia, 9 Hydration of Mortar, 20 Hydrocarbons, 23, 145, 418 Hydrochloric acid. 72 Hydrogen Sulphide, 8 Hydrolitic Defined, 418 Hydrolithic Defined, 418 Hydrostatic Head, 5, 36 Hydrex Compound, 418 Hygienic Effect of Waterproofing, 13 Ice, Specific Gravity, 387 Ideal Mix, 80 Imitatite Defined, 418 Immutability Test, 260 Impervious Roofing, 93, 94, 118 Coatings, 19 Imperviousness Essential, 81 Implements, Sundry, 166, 176 Impsomite Defined, 418 Inert Fillers, 23, 70, 71 Inspection of Waterproofing, 372, 426 Integral Liquids, 15, 25, 28, 74, 75, 418 System, Materials for, 69, 146 - Purpose of, 17, 66, 67, 68, 418 Interior Applications, 29 Internal Cutoffs, 134, 137 Iron Borings, Use of, 143 - Cutoffs, 134 - Oxide, 27 -Powdered, Use of, 146, 147, 149, 375, 418 Sheeting Thickness, 394 Specific Gravity, 387, 393 Isinglass Defined, 418 Joining Membranes, 34 Joint Baffle, 131 - Barrier, 133 - Fillers, 140, 141, 142, 426 Chemical Acting, 143 - Defined, 418 - Rolls, 129, 131 Joints, Effect of, 42, 43 for Bridges, 133 436 INDEX Joints, Effect of, Abutments, 133 in Brick Masonry, 126 Concrete, 62 Forms, 61 Membrane, 34 Jute Fabric, Use of, 46, 47, 48, 111, 160 K Kalinite, 147 Kaolin Defined, 418 Kauri Gum, 72 Kerosene, 29 Kettlemen, 372 Kettles, 50, 54, 179, 373 Knot Hole Fillers, 144 Care of, 114 Knowledge of Materials, 2 Kraemer & Sarnow Method, 198 Labor, 27, 146, 370, 372 Lake Pitch Defined, 418 Land Pitch Defined, 418 Plaster Defined, 418 Lap, Cement, 418 Sealed, 46 Width of, 34 Larutan System, 418 Layer, Defined, 418 Type of Membrane, 41 Leaching, Effect of, 141 Lead Cutoffs, 134 Sheet, Use of, 92, 365 Sheet Thickness of, 393, 394 Specific Gravity, 387, 393, 394 Wool, Use of, 144, 375 Leaks, Occurrence of, 110 Lean Mixtures, 20 Mortars, 25 Lime, 19, 75, 145, 149, 375, 418 Specific Gravity, 387 Stearate, 66 Washes, 61 Limestone, Absorption, 4 Dust, 62, 375 Specific Gravity, 4, 387 Linseed Oil, 93, 145, 147, 375, 418 and Pitch, 236, 237, 238 Specific Gravity, 387 Linseed Oil, Paints, 18 - Use of, 31, 149, 143 Literature on Waterproofing, 1, 426 Lithocarbon Defined, 418 Long Island Railroad Subway, 332 Low Carbon Tars, 418 Lubricant Action, 69 Lubricants, Function of, 67 Lubricating Oil, 36 Lye, Concentrated, 28 M Mabery-Sieplein Method,.198, 202, 203 Machinery, 166 Magnesium Chloride, 9 Oxide, 8 Sulphate, 3, 8, 9 Maltha Defined, 418 Malthene Defined, 419 Manhattan-Bronx Subway, 333 Manhattan Railroad Viaducts, 341 Manhole, 20 Marble, Absorption, 4 Specific Gravity, 4 Martin's Creek Viaduct, 339 Masonry, Specific Gravity, 387 - Solidified, 83 Treatments, 314 Mastic Bond, 249 - Defined, 419 Heating Kettle, 64, 175 Joint Filler, 142 - Materials, 53, 62, 168 - Mixing Kettles, 64, 65, 166, 167, 168, 169, 170, 373 Properties, 242, 247 Roof Flashing, 142 Sheet, 52, 53, 54, 56 Stirrers, 177 System of Waterproofing, 17, 52 Trowel, 183 - Use of, 57, 63, 64, 145, 147, 161 Volume, 62, 248, 390, 391 Wall, 61 - Weight, 390, 391 Mat, Expansion Joint, 139 Materials for Calking, 143 Grouting, 85 Manjak Defined, 419 Meandering Cracks, 127 INDEX 437 Mechanical Acting Materials, 146, 147 153 Analysis, 80, 399 Melting Point Methods, 197, 235, 236 Membrane, Application of, 32, 40, 42, 47 Continuity, 33, 34, 40, 41 Defined, 419 Materials, 146 Mats, 34, 42 Protection of, 34, 35, 36, 37 Reinforcement, 46 Sheet Lead, 37 System of Waterproofing, 17, 31, 419 Mesh Joint, 34 Metal Flashing, 101, 107, 117 - Linings, 31, 33 Primer Defined, 419 Shingles, 120 Metallic Compounds, 23 Metals, 146, 426 Mineral Aggregate, 62, 146 - Fillers, 32 Matter, 143 - Naphtha, 419 Oil, 419 - Pitch, 419 - Rubber, 419 Surfacing, 100 Tar, 419 - Wax, 419 Minwax Defined, 419 Missouri Clay, 71 Mixing Methods, 5, 81 Mixtures of Soap and Alum, 23 Modulus of Elasticity, 12, 125 Moisture Absorption, 15 Monolithic Construction, 125 Mops, 176, 373 Mortar, 23, 25, 26, 82 Defined, 419 Joints, 126, 127 Porosity of, 27, 77 - Protective Coat, 18, 37, 38 Specific Gravity, 387 Tiles, 95 Trowel, 183 Muriatic Acid Applied, 21 Mushy Concrete, 78 N Nailheads Covered, 101 Nailing Base, 94 Nails, Use of, 93, 101, 397 Naphtha, Coal-tar, 23 Defined, 419 - Use of, 31, 145, 147, 161 Naphthaline Defined, 419 Natural Asphalt, 146 Cement, 72, 146, 147, 149, 419 Native Bitumen, 419 - Paraffin, 419 Neat Cement, 82, 145, 146, 147, 150 Necessity of Waterproofing, 1 Neponsit Felt Defined, 419 Neutral Oil Defined, 419 New York Board of Water Supply, 86 Clay, 71 - Dual Subways, 334, 353 Municipal Railway Corp, 343 Testing Laboratory Method, 198, 201 Oak, Specific Gravity, 387 Oil Asphalts Defined, 419 Compounds, 66 - Effect of, 36 Emulsion, 74 Gas Tar Defined, 419 Specific Gravity, 387 Tester, 192 Oil-tar Pitch, 146, 147, 161, 375, 419 Old Laps, 34 Oleate Pctassium, 66 Sodium, 66 Oxidation of Reinforcement, 9 Ozokerite Defined, 419 Ozocerite Defined, 419 Paddle Mixing Machine, 86 Pails Pouring, 167, 177, 178, 373 Painting, 18 Paints, 145 Paint-spraying Machine, 19 Paper Burlap, Use of, 162 Rosin-sized, 108 Saturated, 146 Use of, 32, 162 438 INDEX Parabola, Sand Curve, 81 Paraffin Defined, 419 Paraffine Defined, 419 Naphtha, 419 - Oil, Use of, 163, 419 Solution, 72 Specific Gravity, 387 - Use of, 23, 28, 29, 145, 147, 162, 375 Parapet Walls, 116 Patented Cements, 23, 146 Compounds, 145, 146 Peeling of Stucco, 20, 26 Pellet Method, 204 Penetrometer, 196 Penetration and Temperature, 244, 245 Pennsylvania Railroad Tunnels, 335 Percolation Defined, 7 Permeability Defined, 7 - Effect of, 67 Test, 220, 221, 222, 223, 224, 226, 227, 228 Persulphate of Iron, 93 Petrolene Defined, 420 Petroleum Defined, 420 Grease, 143 - Oil, 23, 146 Specific Gravity, 387 Petrolic Ether, 420 Pig Iron, Use of, 23, 143 Pine Oil, 420 Pine, Specific Gravity, 387 -Tar, 31, 142, 420 Pitch, Asphalt Mixture, 111, 238, 239 - Defined, 420 Linseed Oil Mixture, 236, 237, 238, 239 of Roofs, 104, 105 - Quality of, 49, 51, 52, 146 Specific Gravity, 387 Pipe, Coating, 420 Grouting Process, 86 Mineral Heating, 181 Plane of Weak Bond, 127, 142 Planning and Estimating, 368 Plaster Bond, 420 of Paris, 33, 58, 111, 420 Specific Gravity, 387 Plastering, 16, 18 Plastic Clav. 133 Plastic Roofing, 420 Slate, 142, 420 Plasticity of Bitumen, 32 Plate Steel, 147 Plies, Adhesion Between, 34 Pointing Mortar, 126 Porosity, 3, 7, 78 Portable Kettles, 50 Portland Cement, Use of, 24, 71, 73, 74, 146, 147, 150, 420 Post Holes Treated, 43, 44, 57 Potash, 26 Pouring Pail, 167, 177, 178, 373 Powdered Metals, 27 Powders Finely Ground, 66 Practical Tables, 379 - Tests, 26, 188, 229 Precast Joint Filler, 128 Preparation of Surface, 57, 58 Prepared Roofing, 112 Shingles, 100, 101, 113 Preserving Concrete Tanks, 317 Liquids, 93 Processes, 18 Pressure Tunnels, 357 Priming Coat, 30, 420 Proportioning by Eye, 64 - Effect of, 67 Soap and Alum, 28 Proprietary Compounds, 18, 72, 146 Protective Concrete, 32, 36, 37, 56, 78, 349 Quaking Consistency, 27 Quasi, Colloidal Bodies Defined, 420 Soap Bodies Defined, 420 Quick Lime, 67 R Rag Felt, 32 Railroad, Concrete Roadbed, 346, 347 Drainage, 6 Mezzanines, 344, 345, 347 Viaduct Waterproofed, 337 Joint Filler, 346 Rain, 5 Ready Roofing, 112, 114 Recipes, Practical, 313, 425 Red Rope Paper, 420 INDEX 439 Heduced Oils, 420 Petroleum, 421 Redwood Shingles, 92 Refined Asphalt, 421 Tar, 421 Reinforced Filter Plant, 356 Reservoir, 356 Standpipe, 351 Water Tank, 357 Reinforcement Oxidation, 9 Report on Waterproofing, 408 Reservoirs, 13, 32, 329 Gate House, 325 Residual Oil, 421 Petroleum, 421 - Tar, 421 Resin, 151, 421 Resinates, 67 Retaining Walls, 20, 31, 32, 325 Rich Mortar, 25 Richardson Method, 198, 204 Ridge Roll, 104 Roadbeds Waterproofed, 353 Rock Asphalt, 421, 52 Excavation, 58 Roman Waterproofing, 1 Rondout Tunnels, 358 Roof Drainage, 118 - Gutters, 119 Joints, 106 Simplest, 91 Roofers, 372 - Kettles, 172, 173 Roofing, 91, 110, 319, 426 Cement, 319, 421 Cost of, 91 German, 96 -Gravel, 110,421 Modern, 92 - Mops, 176 - Nails. 397 - Paper, 319 Selection, 91 -Slag, 109, 110,421 Spanish, 96 Roofs in Tropics, 92 Rosin, 145, 147, 421 Specific Gravity, 387 Rubber, Specific Gravity, 387 Rust Joint, 144 S Salamander, 33, 65, 181, 373 Sal ammoniac, 146, 147, 151, 421 Sanborn, Mr. James F., 89 Sand, 25, 50, 62, 71, 80, 85, 147, 375, 421, 426 - Cement, 24, 85, 147, 151, 421 - Drying, 179, 180 - Heating, 181 - Wall, 58, 60 Sandstone, Specific Gravity, 4, 387 Saturant in Felts, 252, 253 - Fabrics, 252, 253 Sawdust, 375 Scientific Proportioning, 3, 78 Scratch Coat, 22 Screenings, 402 Scuttle, 373 Sea Wall Coatings, 24 - Water, Effect on Concrete, 4, 8 Seasoning Concrete Secret Compounds, 145, 146, 165 Seepage, 12 Self-densified Concrete, 17, 68, 76 Materials, 146 Semi Asphaltic Oils, 421 Petroleum, 421 Service Tests, 26, 323 Sewage, Effect on Concrete, 8 Sewer Leakage, 35 Shale Tiles, 95 Sheathing, 146 -Boards, 92, 100, 114 - Paper, 109 Sheet Copper, 94, 97, 146 - Iron, 123, 146 - Lead, 37, 45, 94, 104, 105, 132, 146 - Mastic, 38, 52, 53, 146, 421 - Metal, 147, 393 Piling, 58 Tin, 146 Shingle Roof, 92 Shingles, 92, 93, 101, 104, 396 Methods of Applying, 102, 103, 104 Short, Defined, 421 Shovel, 373 Sieves, 400 Silicates, 66 Silt, Effect of, 125 Slack Barrels, 373 440 INDEX Slag Cement Mortar, 24 Roofing, 94, 109, 308, 310 Slate, Powdered, 31, 63, 111 Shingles, 93 Slates, 4, 387, 397 Slip, Tongue Joint, 127, 128 Slush Coat, 22 Smith Ductility Machine, 211, 212 Smoother, 46, 177, 178, 373 Snow, 5 Soap, 28, 66, 74, 145, 147, 151, 375, 421 and Alum, Action of, 28 Soda Ash Defined, 421 Sodium Chloride, 9 Fluoride, 93 Silicate, 93 Sulphate, 83 Softening Point, 207, 208 Soils Solidified, 83 Solvent, Effect of, 28, 29 Soluble Glass, 421 Spading, 3 Spalls, Use of, 56 Special Cements, 146 Membrane, 45 Specific Gravity of Concrete^ 4 of Materials, 4, 387 Coal-tar Pitch, 197 Petroleum, 197 and Baumc, 381, 382, 383, 384, 385 Resistance of Concrete, 10 of Mortar, tO Specifications, 426 - Asphalt, 267, 268, 269 -Bridge, 298, 299, 300, 301, 302 Caisson, 291 Coal-tar Pitch, 269, 270 Concrete, 273, 305 Creosote Oil, 270 Dampproofing, 273 Fabric, 263, 265, 266 Felt, 264, Floor, 303> 3Q4 Foundation, 278 Hydrated Lime, 271, 272 Integral System, 274 Masonry, 273 Mastic Pitch, 270 Material, 263 Specifications, Railroad Structures, 293, 294, 295, 296, 297 Requisites, 262 Roof, 206, 207, 209, 306, 311, 312 Stucco, 277 Substructure, 279 - Subway, 280, 281, 282, 283, 284, 285 r 286 Surface Coating, 275, 276 - Tunnels, 280, 287, 288, 289, 290 - Waterproofing, 273 Writing, 263 Spruce Shingles, 92 Staggered Type Membrane, 41 Standard Methods for Bridges, 294 Standing Seam Roofing, 106, 108 Staves, as Fuel, 50 Steam as Fire Extinguisher, 50 Insulation, 45 Steam-pressure Placing Machine, 89 Stearates, 28, 67, 72, 75, 143, 146, 147, 152, 153, 421 Steel Plate, Use of, 163, 146, 367, 387, 394 Reinforcement, 12 Stirrers, 177, 373 Stone Aggregate, 78-, 80; 163 Average Weight, 4 Duplication of, 3 Preserving Composition, 316 Screenings, 86,147, 374 - Slab Roof, 92 Storing, Effect of, 48 Structural Bodyguard, 2 Structures, Bane of, 3 Stucco, 25 Subaqueous Tunnels, 362 Subsurface Structures, 350 Subway Asphalt, 421 - Pitch, 421 Subways, 7, 32, 47, 48, 55, 354 Suet, 145, 147, 153, 421 Sulphuric Acid, 8 Anhydride, 8 Supervision, Effect of, 3, 45, 76, 77, 81 Surface Coating Compounds, 23, 25, 30, 72 System, 9, IT, 18> 19, 26, 145, 315, 323, 421 Preparation, 33, 58 INDEX 441 Swimming Pool, 20, 25, 352 Switch Pits, 36 Sylvester Process, 17, 28, 421 Tables, Explanation of, 379, 386 Tallow, Specific Gravity, 387 Tamper, 373 Tank Treatments, 24, 317 Tar and Gravel Heater, 175, 174 - Use of, 141, 145, 147, 164, 422, 423 Technical Tests, 188 Temperature, Effect of, 2, 4, 11, 125, 241, 251 Tensometer, 210 - Mold for, 211 Terne Plate, 105 Terra Cotta, 37, 58, 387 Terrazzo Floor, 231 Tests, Asphalt, 189 -Determination, 190, 191, 192, 194, 195, 198 Drop Point, 205 - Ductility, 209 - Flash Point, 191 Flow Point, 208 - Identification, 212, 213, 217, 218 - Practical, 219, 229, 231, 234 Publications on, 426 Specific Gravity, 190 - Waterproofing, 188, 189 Texene, 422 Thatch Roof, 91 Thawing, Effect of, 2 Thermometric Equivalents, 380 Thompson, Sanford E., 69 Tiles, 52, 99, 146, 387 Shingles, 95 Timber, Use of, 22, 50 Tin, 384, 393, 394 - Cutoffs, 134 Drain, 33 Flashing, 94 Plate, 105, 106, 108 - Roofing, 92, 105, 108 Tongue and Groove Joints, 133 Tools, Applicability of, 166 Torch, 57, 178, 373 Torpedo Gravel, 422 Trap, Specific Gravity, 4 Treated Materials, 147 Trial Mixtures, 80 Trinidad Asphalt, 143, 422 Trough, 58 Trowels, 182, 373 Tunnels, Grouted, 83 Penn. Railroad, 20, 29, 31, 32, 33, 39, 326, 327 Turpentine, 375, 387 Tun-eUite, 422 U Ultimate Tensile Strength, 12, .125 Uneven Settlement, 2, 4, 13 United States Bureau of Standards, 8, 27, 68, 69, 71, 74 Capital Terrace, 340 Varnish Gum, 422 Vibration, Effect of, 13, 67 Vintaite Defined, 422 Viscosity, 422 Viscous Priming Coat, 30 Vitrified Tibs, 6, 45 Voids, Determination of, 7, 78 - Filling Materials, 3, 146 Volatile Defined, 422 Oil, 49 Volumetric Synthesis, 80 Tests, 80 W Walls, 58 Water, 147 Absorbent, 422 - Diverted, 84 Effect on Fabrics, 254 Ejecting Grout Machine, 87 Evaporation, 77 Gas Tar, 164, 422 Glass, 75, 422 Repellent, 3, 67, 422 Pressure, 18, 63, 392 Specific Gravity, 387 Storage Works, 323 - Table, 5, 422 Universal Solvent, 1 - Use of, 22, 50, 99, 164 Works Reservoir, 328, 360 442 INDEX Waterproofers, Graded, 370, 372 Waterproofing, Adaptability, 82, 422 Applied, 323 Art of, 1 Cements, 320, 321 Compounds, 313, 314, 321, 322 Economy, 16 Fabrics, 426 Failures, 124 Implements, 166 - Materials, 145, 389, 426 - Mortar, 314 Paste, 72 Progress, 17 Projections, 43 Publications, 425 Roof Coverings, 395 Specifications, 262 Steampipes, 43 Systems, 17 Watertight Roofs, 91 Wax, 387 Weak Bond Plane, 133 Weather and Waterproofing, 66 Weep Holes, 6 Weight of Implements, 373 - Materials, 374 Wet Surface, 66 Wheel Barrow, 181, 373 Wood Cores, 373 Flour, 375 Shingles, 92 Spreader, 183 Wooden Tanks, 318 - Floor, 319 Wool Felt, 32 Workmanship, 77, 81 Wurtzelite, 422 Yoke, Pail Carrying, 179 Zinc Borate Paint, 93 Chloride, 93 Coefficient of Expansion, 387 Cutoffs, 134 Roofing, 106 Sheeting, 105 Specific Gravity, 387 UNIVEESITY OF CALIFORNIA LIBRARY, BEEKELEY THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW Books not returned on time are subject to a fine of 50c per volume after the third day overdue, increasing to $1.00 per volume after the sixth day. 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