k JL l 0* -y If s> A.MV Fa rlan A.]Nt Parian. A BRIEF PRACTICAL TREATISE ON MORTARS: AN ACCOUNT OF THE PROCESSES EMPLOYED PUBLIC WORKS IN BOSTON HARBOR. BY LIEUT. WILLIAM H. WRIGHT, UNITED STATES CORPS OF ENGINEERS. BOSTON: WILLIAM D. TICKNOR & COMPANY, MDCCCXLV. Entered according to Act of Congress, in the year 1845, by William H. Wright, in the Clerk's Office of the District Court of the District of Massachusetts. BOSTON: PRINTED BY THURSTON, TORRY &. CO. 31 Devonshire Street. PREFACE. Many able works have been written on the subject of mortars. But no one of those, with which I am acquainted, contains enough of detail to afford much assistance to inexperienced constructors ; and they are, in general, so voluminous, and withal so badly arranged, that the information which they contain can only be acquired after laborious research. The neces- sary consequence follows, that few read them, and the composition of mortars, upon which the stability of structures so «much depends, is in most cases left entirely to the judgment of uninformed workmen. Such a system must obviously lead to the worst prac- tical results, and indicates an absolute necessity for some new effort upon a subject so important. At the request of the Chief Engineer, and with the hope of inducing constructors to bestow some personal IV PREFACE. attention upon the mortars which they employ, these pages have been drawn up. They embrace every- thing of practical interest that I could obtain from the existing treatises at my command, as well as the re- sults of my own experience at Fort Warren, Boston Harbor, while acting as the assistant to Col. Thayer, of the Corps of Engineers, United States Army. For the drawings accompanying the text, I am indebted to Lieut. H. L. Eustis, of the United States Corps of Engineers. Boston, May, 1845. TABLE OF CONTENTS. CHAPTER I. Calcareous minerals, and the limes which they furnish. — Lime, whence and how obtained. — Limestones, how distinguished. — General properties of lime. — Classification of limes into fat limes, poor limes, hydraulic limes, and hydraulic cements. — Characteristics of these different limes. — Relation between the qualities of the limes and the chemical constitution of the stones whence they are derived. — Magnesian limestones. — Carbonate of magnesia. — Plaster of Paris, or sulphate of lime, . . 1-14 CHAPTER II. The various materials employed in the preparation of mortars. — Comprised under three heads, to wit, the limes, the sands, and the pouzzolanas. — Poor lime. — Fat lime. — Hydraulic lime. — Slaking of lime, three modes of, with remarks upon each. — Hydraulic cement. — Sands. — Classification of sands. — Mode of clearing sands. — Use of sand in mortars. — Pouzzolanas, classification of, into natural and artificial. — Pouzzolana prop- er. — Trass or terras. — The Arenes. — Clays, how examined. — Brick or tile dust. — Forge scales and minion. — Slag from the iron foundries, 14-38 VI CONTENTS. CHAPTER III. Pages. On the general composition of mortars. — General principle. — Modes of measuring void spaces in sands. — Economy of using mixed sands. — Mode of determining proportions when mixed sands are used. — Minimum of cementing matter in mortars. — Reasons for increasing this in practice. — Rule in using pouzzo- lanas. — Rule in preparing mortar for masonry in general. — Table of twenty different compositions used by Smeaton in the construction of the Eddystone lighthouse, and other works, . 38-52 CHAPTER IV. On the resistance of mortars. — Considered under four points of view. — Comparative strength determined, by breaking with weights, prisms of the different mortars. — Apparatus used for the purpose, described. — Modes of testing the adhesiveness of mortars. — Cohesive strength of pure hydraulic cement, illus- trated. — Brunei's experimental semi-arches described. — Mode of determining the comparative hardness of mortars, . . 52-61 CHAPTER V. On the fabrication of limes, &c. in the large way. — Kilns for burning lime, divided into two classes. — Various kinds of kilns described. — Combination of coke oven with lime kiln. — Man- agement of the burning. — Mode of mauufacturing hydraulic cement. — Mode of restoring its qualities when damaged. — Manufacture of artificial cement. — Manufacture of artificial pouzzolana, 61-78 CHAPTER VI. On the preparation and application of various kinds of mortars. — Mortars classified. — Ingredients of mortars and mode of mea- suring them employed at Fort Warren. — Mortar for pointing, its mode of preparation and application. — Mortars for interior and exterior stucco, how prepared and applied. — Ordinary mor- tars (fat lime and sand). — Implements used at Fort Warren in making mortar. — Mortar-mill, with its appendages, described. — Mortars for stone and brick masonry. — Manipulation of these mortars. 78-106 CONTENTS. Vll CHAPTER VII. Pages. On concrete and some of its applications. — Mode of preparing concrete. — Various kinds of, used at Fort Warren for the foun- dations and superstructure of walls, and the roofings of case- mates, described in detail. — Advantages of employing concrete in constructions, 106-128 CHAPTER VIII. Theory of the solidification of mortars, 128-141 Index, 141-148 A.MV Farlan. TREATISE ON MORTARS. CHAPTER I. CALCAREOUS MINERALS, AND THE LIMES WHICH THEY FURNISH. 1. The material from which lime is usually c i a I bocate , . , * , . . i ol ,,me ' un extracted, is a carbonate of June, or, in other abundant words, a chemical compound, the essential com- "" !iu a c t pr ° ponents of which are lime and carbonic acid. This substance is widely diffused in nature, and exhibits so many varieties of form and structure, that it would be scarcely possible to enumerate them all. 2. The calcination of each variety of lime- o™ species stone furnishes a different product, with proper- h6w™ob- ties peculiar to itself. Yet, in truth, there is but la ' no<1 ' one species of lime (the protoxide of calcium), that which is obtained by calcining pure white marble. All the other products, called heretofore meager lime, hydraulic lime, &.C., are only nat- ural mixtures of lime and sand or crude earth, existing originally with water and carbonic acid in the impure limestone.* 3. Lime is obtained principally from calca- substances reous minerals, but there are some localities, limas." where it is procured from marine deposits, oyster * Raucourt sur les Mortiers, page 2. 1 & TREATISE ON MORTARS. shells, madrepores, animal products ; these, how- ever, are rare cases. * Mode of 4. Minerals of the calcareous class always 'in? n ?ime- dissolve, either wholly or in part, in weak acids, sumes. ^y.jj.jj more or less brisk effervescence, and may be scratched with an iron point, f They are sometimes found pure, in the form of calcareous spar and white marble, but more usually contain oxide of iron, and sometimes a certain quantity of sand, alumina, magnesia, oxide of manganese, &c. % Pure lime. 5. An analysis of white marble by Gen. Treussart gave for its component elements — carbonic acid, 33; lime, 64; water, 3. If a portion of this mineral be reduced to powder, and heated to whiteness in an open crucible, the carbonic acid and water which it contains are driven off, and lime remains in a pure state. It is then in the condition of quick or unslaked lime, with a specific gravity of 2.3. § Slaking de- 6. If pure lime, immediately after being cal- cined, is mingled with a proper quantity of wa- ter, a large amount of hot vapor is evolved, and the lime is reduced to a thick, clayey paste, equal in bulk to more than three and a half times its original volume. || The lime is thus brought to a thorough state of division by the addition of water (with which it enters into chemical combination), and is now said to be slaked. Properties 7. Pure quick lime has a great avidity for water, imbibing it rapidly from the air, and forming with it a chemical compound, termed hydrate of lime. This compound contains about * Raucourt, pacre 121. t Smith's Vicat, page 1. t Totten's Treussart, page 2. § Ibid, page 1. || Raucourt, page 1C. lined. of lime. LIMESTONES AND THEIR LIMES. 5 twenty-eight parts by weight of lime to nine of water, and is always formed during the pro- cess of slaking,* though the lime, in acquiring a. pasty consistence, absorbs a much larger quan- tity of water. In truth, if it be pure, and is supplied with water as soon as it comes from the kiln, it will absorb three and a half times its weight — a property peculiar to lime, and serving to distinguish it from other earths, f Pure quick lime, when converted into paste by the addition of water, will retain its soft consistence, as long as it is kept damp. It is, however, dissolved very sparingly by water, though it possesses the singular property of being more soluble in cold than in hot water. J It has a great affinity for carbonic acid, at- tracting it readily from the atmosphere, and can only be preserved pure by being kept in close vessels. 8. In the preceding remarks, I have spoken ciagsifica- of pure lime. The lime, however, which is tl fa M £ i used for building purposes, is rarely in this state, but, besides water and carbonic acid imbibed from the atmosphere, contains usually some of the foreign substances mentioned in Article 4. These substances modify the properties of pure lime, and, when combined with it in certain proportions, entirely change its nature. It will therefore be convenient to arrange the limes employed in constructions into four different classes: 1st. The fat or common limes; 2d. The poor or meager limes ; 3d. The hydraulic limes ; and, 4th. The hydraulic cements. 9. The fat or common limes are more than Fatiimc*. doubled in volume during the process of slaking, * Capt. Smith's Vicat, pasje 34. t Raucourt, page 2. $ Turner's Chemistry, page 311. 4 TREATISE ON MORTARS. which is always attended with much heat. If converted into paste and immersed in water, they will remain of soft consistence forever ; and they are soluble to the last particle in pure water, if it be frequently changed.* Builders call them fat limes, because the paste, which they form with water, is soft and unctuous to the touch. Poor iimc?. 10. The poor or meager limes include all those which, in slaking, do not undergo an in- crease of volume equal to twice their original bulk, but exhibit, when immersed, the same qualities as the rich limes, with this difference, that they dissolve more partially in water, leav- ing usually a large residue of insoluble matter, f Hy.irauiic 1 1. The hydraulic limes possess the property iimes. £ se fij n g i in( ier water, in periods of time vary- ing from one to forty days after immersion, and continue to harden more or less rapidly, accord- ing to the hydraulic energy which they respect- ively possess. They all slake, but with diffi- culty ; the stronger kinds exhibiting few or none of the appearances usually seen in fat lime during the slaking process, little or no vapor being formed, and scarcely any heat disengaged ; and they undergo an increase of volume, in the inverse ratio of their hydraulic energy. f Hydraulic 12. The hydraulic cements differ from the limes, in not slaking at all after calcination, unless they are previously pulverized ; and they then form a paste with water, without any per- ceptible disengagement of heat, or augmenta- tion of volume. They contain a large amount of the hydraulic base or principle, and set under water in a much shorter time than the limes require to set in air. * Smith's Vicat, page 6. t Ibid, pages 6, 7. LIMESTONES AND THEIR LIMES. i 13. In the preceding articles, the term setting Setting With regard to the size of the grains, experiments show that there is an advantage to be gained from the employment of fine sand with the hydraulic limes, though they establish nothing with regard to its superiority over coarse sand, in combinations \v\iX\ fat lime. || 51. All the sands should be carefully exam- F^aminn ined before they are used ; for river sand and even sea sand are not always exempt from earthy powders, which, experience proves conclusively, are often very injurious to mortars. Pure sands, * Vicat, p. 85. t Rondelet, Art de BAtir, pp. 130, 132. t Totten's Treussart, p. 113. § Raucourt, p. 22. || Smith's Vicat, p. 87. — Totten's Treussart, p. 105. 3 tion of samls. 20 TREATISE ON MORTARS. rubbed between the fingers, should leave no stain, and, immersed in limpid water, should at once fall to the bottom, without altering the trans- parency of the liquid in a sensible degree.* Should the water become muddy, it is an indi- cation of the presence of some foreign matter, the nature and proportions of which it is impor- tant to ascertain, as it may possibly possess hy- draulic properties. In order to determine these, place a portion of the sand in a vessel of water, agitate it thoroughly, and then pour off the water into a separate vessel of larger size ; add- ing fresh water to the sand, repeat the operation, until the granular particles alone remain in the first vessel, after the decantation. Allowing the turbid water, resulting from the several washings of the sand, to remain tranquil for some hours, decant it gently, and the powders that originally formed part of the substance under trial will then be left behind. They should be carefully dried and measured, and the proportion, which they bear to the sandy particles, may now be easily determined.! We are not yet acquainted with the properties of the powders, however ; and, with the view of discovering if the sand is at all hydraulic, make two cakes or mixtures with fat lime, one with two measures of the powder, the other with two measures of the sand in its original state, to one of lime paste, and test them in the mode recommended in Article 18. If either cake exhibits hydraulic qualities, the sand may be classed as a puozzo- lana. If they both remain soft after a month's immersion, we may infer at once that the powder has no useful quality. It should, in this case, * Smith's Vicat, p. 43. + Raucourt, pp. 55, 56. INGREDIENTS OF MORTARS. 27 be separated from the sand, unless it exists in small quantity, and reasons of economy balance the injury which the sand may experience from its presence.* As to the sandy particles obtained in the analysis, we may separate them into coarse, fine, and middling sands, by means of sieves, properly selected, and ascertain, by measuring the void spaces of each, if they exist in proper proportions ; and, if they do not, what, kind of sand should be added to them, to form the best mixture for mortar. See Article 81. 52. When sand contains earthy impurities to Mode or any extent, it must be thoroughly washed, in cl (3 ! order to be rendered suitable for mortars. This may be done on the large scale in the following manner, recommended by Gen. Treussart : Near the well or pump, construct, either of masonry, or, more economically, of plank, a basin of con- venient size, say eight feet long and four feet wide, with a depth of two feet two inches, except on one end, where the wall or side should be only fourteen inches in height. The gap, thus made in the end of the basin, is closed by a movable plank, which works in grooves, fitted to receive it, in the side walls. A layer of sand about a foot thick is then placed in the basin, and the latter filled with water from the pump. The sand must now be well stirred up by two or three laborers, and, after it has been allowed sufficient time to fall to the bottom of the basin, the movable plank is suddenly withdrawn, when a great part of the water will pass off, loaded with the earthy matter. The operation should be repeated until the water appears but slightly * Raucourt, pp. 55-57. 28 THEAT1SE ON MORTARS. turbid ; the sand is then taken out to dry, and the process may be applied to other portions.* Use or 53. Sand performs no chemical part in mor- mortaia. tars, but is entirely passive in its influence ; it appears rather to diminish the adhesiveness or tenacity of the limes, and, though it may often add to their resistance, is employed chiefly for reasons of economy. It is useful, however, as an ingredient of mortar, in some other respects; it moderates the shrinkage of the cementing matter, making it uniform, and preventing cracks ; probably facilitates desiccation, and makes the induration more rapid. f Sand diminishes the strength of hydraulic cement in every respect, whether we regard tenacity, resistance, or the property of setting under water ; though a mixture of cement and sand for stucco and pointing mortar is better than pure cement, as being less liable to crack, and therefore more durable, when exposed to the sun in hot weather. In general, a moderate portion of sand is mingled with cement, for the sake of economy, except in peculiar circum- stances, on very important works.| POUZZOLANAS. rouzzoia- 54. The substance commonly known as pouz- '"' zolana, is a volcanic product, deriving its name from the village of Pouzzoles, at the foot of Mount Vesuvius, where it is found near the sur- face of the ground. But the word pouzzolanas is here used as a general term, and under it will be comprised all those products, which, without * Totten's Treussart, p. 154. t Ibid. p. 105. t Pasley, pp. 41, 202, 203. INGKEDIENTS OF MORTARS. 29 containing lime as a principal constituent, form with it combinations, which possess the property of setting under water. 55. These substances offer very important ad- Remarks on , . c . j pouzzoli vantages in the improvement ot mortars, ana n as. deserve particular attention, because hydraulic cement is not always to be had, and hydraulic limes often give mediocre results, unless they are mingled with a certain proportion of pouzzo- lana ; and the latter has, moreover, this advan- tage over the hydraulic limes, — its qualities are scarcely at all impaired by exposure to the air and moisture. The essential constituents of pouzzolanas are silica and alumina, and their elements have in general undergone, through igneous action, a change in their primitive mode of combination. Now, as the intensity of this action may be very various, it is easy to conceive that a great differ- ence may exist in their qualities, though their chemical constitution may remain the same.* 56. Pouzzolanas may be divided into two ciassifiea- classes ; the natural and artificial. The first in pouTzoiu- their natural state, possess the property of form- nas- ing hydraulic mixtures with fat lime. The second are obtained by the calcination of certain natural products, which, without being burned, would have no action upon fat lime ; but, prop- erly calcined, have equal efficacy with those of the former class. Under the head of natural pouzzolanas may be comprised, pouzzolana prop- erly so called, tras or terras, and the arenes. 57. Few regions exposed to igneous agency Ponzzoium are without -pouzzolana. It presents itself under I>roper- various physical appearances. It is sometimes * Totten on Mortars, p. 169. 3# 30 TREATISE ON MORTARS. pulverulent, sometimes in coarse grains ; and though generally of a brown color, is also found white, black, yellow, gray, red and violet. A specimen, analyzed by M. Berthier, gave, in one hundred parts, 44.50 of silica, 15. of alumina, and 8.8 of lime, besides small proportions of magnesia, oxide of iron, potash, soda and water.* Pouzzolana has no cementing properties in itself, but its qualities may be tested in the manner prescribed in Article 51. One measure of lime paste to two of pouzzolana powder, if the latter is of very good quality, should set under water in four days. Pouzzolana must always be re- duced to the state of an impalpable powder, before it is employed as an ingredient of mortar, as it acts, only when thus pulverized, with its full energy upon lime. It does not add much to the tenacity of fat lime, but augments its resist- ance in a remarkable degree. The weaker hy- draulic limes are always improved by the addition of pouzzolana ; the eminently hydraulic limes and hydraulic cement are always injured by its use.* tnm. 58. Trass or terras is obtained near Andernach, on the Rhine, from the village of Brohl, situated at the foot of an extinct volcano. It is of a grayish color, much resembling gray clay which has been calcined, and is found in lumps or par- ticles of various sizes, from that of a pea to that of an egg. Its general properties are the same as those of pouzzolana. Like that substance, it is prepared for use by being pulverized, and it has the same chemical constituents, though in somewhat different proportions. It will cause most limes to harden under water ; yet Smeaton * Totten's Treussart, pp. 52, 53.— Pasley, pp. 182, 202, 205. INGREDIENTS OF MORTARS. 31 regards it. as inferior to pouzzolana, in some re- spects. In a state between wet and dry, or of being wet and dry at intervals, it does not answer well, but becomes friable and crumbly. Smeaton further remarks, that, when always wet, and in a state most favorable to its cementing principle, it throws out a substance resembling stalactites, which becomes in time very hard, and deforms the face of walls : indeed, when smoothness and regularity of surface are required, as in navigable sluices and the like, it becomes necessary to re- move with instruments, the stony excrescence which it forms. This effect may have been produced, however, in consequence of Smeaton's using too large a proportion of lime with his terras, a proportion which should rarely exceed the ratio of one to one. General Pasley thinks it is not peculiar to trass, and recent experiments give the substance a very good character.* 59. A species of fossil sands, of very singular Arenea. properties, was discovered in France, a few years since, by M. Girard de Caudemberg. He gives them the name of arenes, to distinguish them from other sands. They may be made into a paste with water, and are often used alone, as a pise, in building the walls of houses, as they shrink less than clay, and resist better the in- clemencies of the weather. But they possess a more important property. When mingled with common fat lime, they form mortars, which set under water, and acquire great hardness. M. Girard built several locks with mortar composed of common lime and the arenes, and obtained very good results. It was necessary to use the pick, to break up concrete * Totten's Treussart, pp. 52, 53, 55.— Vicat, pp. 17S, 179. 32 TREATISE ON MORTARS. that had been made with them the year be- fore.* Physical 60. The arenes are widely distributed through- characters ,-n i . • r i ■ i i of the out r ranee, and sometimes round in beds more arenes. ^^ f^f* t y f eet thick. They are usually discov- ered on the summit of hillocks, which form the basins of brooks and rivers, and have all the characters of an alluvial deposit, though rarely met with in valleys. The color of the arenes is very various : they are red, brown, yellow, and sometimes white. M. Girard examined several kinds by repeated washings and decantation, and found that they were all composed of sand mixed with clay, in various proportions, from ten to seventy per cent. The sand is sometimes fine, sometimes coarse, occasionally calcareous, but more frequently siliceous or mixed.* Energy in- 61. The arenes form, good hydraulic mortars c^ictnation. with fat lime, when used, either in their natural state, or after undergoing calcination. Two mortars containing equal proportions of crude energetic arenes, and the same arenes calcined, showed no appreciable difference in their con- sistence, after a year's immersion in water. The torrefaction of the arenes, however, hastens their induration in a remarkable degree.* rropenies 62. Properties resembling those of the arenes ar°enes e in have also been recently discovered by M. Avril giaywacke " in graywacke, and even granite, when in a state of decomposition. Their hydraulic quality is, however, feeble, though it acquires increased energy by a slight calcination. Remarks 63. As the arenes are found in great abundance U a'r o Er o 5 3 J* 13 a O O s o oi *> co to i- 1 WH S-a M-i*- h- jo ,-_;___ ?r ffi jo to jo jo jo to M W *• CO M M OHHMKI*. O O ^ l-> «0 O M W W-KH HMHW cr S w co co to i-i : ■u. iu ic>. co to to OHH MtOCO! o-a> The materials in the above mixture were measured dry. The lime in powder was thrown into the bushel and " stricken," but not beaten nor pressed down. TREATISE ON MORTARS. CHAPTER IV. ON THE RESISTANCE OF MORTARS. Remarks. 91. We have supposed, in a preceding chapter, that a cement or mortar has set, when it bears, without depression, a wire one twenty-fourth of an inch in diameter, and loaded to weigh one pound. Now, after this condition has obtained, the mortar still goes on constantly to harden, and, according to its quality, acquires in a defi- nite time, a certain amount of strength. It there- fore becomes important to know some simple means of measuring the resistance of mortars, at different intervals of time after their preparation ; and I now propose to describe some of the meth- ods, that have been employed with advantage, in experiments with this view, strength of 92. The strength of mortars may be consid- mortars to ~ ■> be consid- ered, with reference, first, to their resistance to a ered under , . . , ' ,. . . four points crushing weight; secondly, to their resistance to a force of fracture ; thirdly, to their adhesiveness ; and fourthly, to their hardness. The first 93. If we confined ourselves to experiments P quYry noT indicated by the first head, it would not be easy al °ci e ent. ffi ' to arrive at a correct estimate of their compar- ative strength. For, if prisms of the different mortars were loaded with weights, as some direct, until they were actually crushed, it would be difficult to determine the moment when they began to give way, as the angles often break before the centre, and it is not clearly seen, when the substance under exam- RESISTANCE OF MORTARS. • 53 ination has really yielded to the load * It may, therefore, be well to limit the examination to the three latter points of inquiry, indicated in the preceding Article : and I will at once proceed to describe the method employed by Treussart and Pasley, in measuring the resistance of mortars to a fracturing force. 94. A convenient form to give the specimens Mortars to - . t t r ■ • 1 /• 1 De moulded oi mortar intended lor experiment, is that 01 the into prisms, parallelopiped, into which they may be easily moulded by means of a box of the proper dimen- sions, say six inches long, three inches wide, and three inches deep. (Fig. 1.) Having fixed piatei. the proportions of the mortars to be tested, the lime or cement may be measured in the state of paste, as this mode is ordinarily pursued in prac- tice. The cementing matter, whatever it may be, being then added to the sand or other sub- stance, which should in every experiment be carefully measured in the same manner, the whole may be brought to the requisite temper, by pass- ing it seven or eight times under the trowel. The mortars being thus made, and all of the same consistence, should then be put into the prism mould, and every specimen subjected to the pres- sure of the same weight, say six hundred pounds. When the mortars have stiffened sufficiently, they may be taken from the mould, and set aside, either in water or in the air, until it is desired to submit them to experiment. It sometimes hap- pens that the exterior of the prisms is harder than the interior, while at other times the contrary obtains. For this reason, it was Gen. Treussart's custom to cut off with a chisel about half an inch from each side, in order to remove every part that had a different hardness from the interior. f * Totten's Treussart, p. 17. t Totten on Mortars, p. 17, 252. 5* 54 TREATISE ON MORTARS. Mode of 95. The prisms having attained the age de- the^prisms. sired, their comparative strength maybe ascer- tained by breaking them down with weights applied to the middle of each prism, which is supported at the ends, during the operation, by a couple of iron stirrups, placed at the clear dis- tance of some four inches apart. A convenient Plate i. apparatus for this purpose is shown in Fig. 2. Before the mortar is placed upon the stirrup bearers, another iron stirrup, inverted, is passed over one end, as far as the middle of the prism. The top of the stirrup thus rests upon the upper surface of the prism, while to its bottom, which is open, is then hooked on a light scale-board, upon which the weights are placed, and gradu- ally increased until fracture takes place. Further de- 96. That part of the surface of the two sup- 8 t : he P appar - f porting stirrups, upon which the prism of mor- atus. j. ar rests, is flat, while the inverted stirrup rest- ing on the top of the prism, has the form of a blunted knife edge (Fig. A. e). The stirrups and scale-board are suspended under a gin (or triangle for supporting weights) by means of ropes, or rods of iron, though the cap of a large trestle, or a beam sufficiently strong to support the appar- atus, may be substituted in place of the gin (Fig. 2, B). If the scale-board be too small to hold the necessary weights, we may place upon it a couple of three inch planks, which may then be loaded, from the centre outwards, by two or three parallel rows of weights, as the case may require. (Fig. 2.) Form for 97. As soon as fracture takes place, the break- 'SesnJta! 6 ing weight, including, of course, the weight of the scale pan and its appendages, should be re- corded in some convenient table like the follow- ing, which will show immediately the results obtained by mixing different sorts of lime or RESISTANCE OF MORTARS. 55 cement with various proportions of gravel, sand, or both.* When made. No. of Exper- Lime or cement paste, mixed with G (gravel), S (coarse sand), s (fine sand). If kept under Age when broken, in days. Proportion of paste to Frac- turing weight in pounds. ago when immersed. Sand. Gravel and sand. Compact. 1833. May 7. 1 Rich lime (Smith- field), 1 S 2. 50 1 to 2 164 1-2 98. A common method of comparing the adhe- siveness of different mortars is to stick bricks together with each mixture, in rows projecting from the side of a brick wall. Before commenc- ing one of these rows, a small rectangular portion of the wall, sufficiently large to receive the first brick, should be well scraped, and the joints of the brick-work carefully raked out for about half an inch in depth. The wall, thus prepared, must now be plastered, and its joints completely filled with mortar, and the first brick should be at once applied, before the mortar in the joints has be- come at all stiff. Whenever a new brick is to be added, it is well to immerse it in water for half a minute, and to wet also, with the aid of a brush, the face of the wall or brick to which it is to be attached. The mortar should then be carefully applied to both surfaces ; first in a thin coat to the wall or brick already in place, and then in a thicker coat to the new brick, and the two should now be joined together, mortar to mortar, and well pressed for some fifteen or twenty minutes. No new brick ought to be added until the mortar of the preceding one has become perfectly set.f Mode of estimating the adhe- siveness ot mortars. * Pasley, pp. 112, 131, 134. t Pasley, p. 108. OD TREATISE ON MORTARS. Ve'sfof" "■ The method just described is best adapted hydraulic f or testing the adhesiveness of quick setting mix- tures, and affords a simple and striking illustration of the uncommon qualities of hydraulic cement in that respect. Capt. Smith, the translator of Vicat, mentions an instance in which 33 bricks have been thus successfully supported. Now, if the weight of the brick and its corresponding joint regarded as homogeneous, be assumed to be six pounds, and their thickness, when the bricks are joined together, in the way before- mentioned, in which the longest dimension is placed vertical, at 2£ inches, then the strain upon the first joint would be equivalent to that pro- duced by a weight of G534 pounds, suspended at the centre of gravity of the first brick.* Adhesive- 100. But the extraordinary strength of pure hydraulic cement is proved, in a more wonderful man- Thernius-" ner, by two semi-arches, built for experiment by tnted. ]y[ r Brunei, near the entrance of the Thames tunnel. This arrangement is so ingenious, and will, probably, be found hereafter of so much value in practical architecture, that it may be well to describe it, though not strictly in keeping with my plan. The arches spread out from the same common central pier (like two branches from different sides of a tree), one 60 feet, the other about 37 feet long, the rise of the former being 10i feet, and that of the latter about 10 feet, and at the extremity of this last was sus- pended a weight of 62,700 lbs. Two views of these semi-arches are shown in Plate i. Figs. 3 and 4. The pier from which they sprang, measured in extreme length, 10 feet, and in width, 4 feet (the last only appearing in elevation), and * Smith's Vicat, p. 112. RESISTANCE OF MORTARS. 57 its extreme height above the ground was 8 feet. The arches were 13 inches in depth or thickness, and 3 feet 6 inches wide, and the cornice, with which the one coincided, and the other nearly so, at their outward extremities, was also of the same width. The width of the brick-work, however, in the spandrels, or intermediate spaces on each side of the central pier, above the spring of each semi-arch and below the cornice, and within the openings of the seven small arches, which projected on one side about a foot from the spandrels, was only 18 inches. The brick-work was bonded with 10 tiers of 3 wooden laths each, commencing at the height of 4£ feet above the ground, and laid horizontally in the joints of the spandrel courses. Above these it was bonded with 12 tiers of hoop iron, also laid horizontally in the joints of the remain- ing courses of the spandrels, and in those of the cornice, in the following order as to number, viz. ; in the lowest joint two pieces of hoop iron, in the second 3, in the third 4, in the fourth 5, in the fifth, sixth, seventh, eighth and ninth, each 6, in the tenth 4, in the eleventh 6, above which one more course of bricks completed the whole height. Now although much must be ascribed to the pieces of hoop iron introduced horizontally into the joints, inasmuch as cement alone can only support a certain limited number of bricks ; still, unless it had the property of setting almost instantaneously, and uniting the brick-work into a solid mass, the hoop iron, of itself, could give but little stability to a structure thus suspended in air.* 101. The method of testing different mortars second and cements by setting out bricks from the side teSttagad- of a wall, though very easy of application, some- hesiveness - *Pasley,p. 39, 116. 58 TREATISE ON MORTARS. times leads to doubtful results, if executed by different persons in a different manner, or in dif- ferent states of the weather. A better method is to employ the breaking-down apparatus before described, consisting of the scale-board, planks and weights, and, in addition, a couple of pairs of nippers to be used with the gin, or other suit- able means of suspending the apparatus. In place of bricks, Gen. Pasley recommends a number of pieces of any sound, hard stone, each 10 inches long, 4 inches broad, and about 4 inches thick, and furnished with mortises in the sides. These mortises are each one inch wide, one inch deep, and from £ to half an inch in height, and should have at least 2J- inches of solid stone above and below them. They are intended to receive the nippers, after the stones have been cemented in piate i. pairs, as shown in Fig. 5. The rectangular sur- face of the stone, where the mortar is to be applied, should be well roughened, and all the surfaces made as nearly alike as possible. The joint should be about ■§ of an inch thick, and in order that the mortar may be equally consolidated in every case, it is well to subject each set of stones to the pressure of some 600 lbs. for five minutes after they are joined together. The mortars experimented upon should have ample time to set, before the breaking-down apparatus is applied, and the trials with each specimen should be multiplied as far as conve- nience will permit. The little blocks of stone, if cleaned after each experiment, may be used for years with advan- tage. We have only to make the nippers and mortises fit rather tightly, and to prevent the stones from falling to the ground, when the joint is fractured.* * Pasley, pp. 126, 127. RESISTANCE OF MORTARS. 59 When stones cannot be obtained without in- convenience, bricks may be substituted in their place, the nippers being slightly modified. 102. The following table from Gen. Pasley's £°™ ° r s s t-i — Hj 5' p e 3 — o i a p 3 ~ a ! i' - s p p p' p ■5 p =_ <& o ='=• O •-> 9 ? -> 5 p 5 p 3 S o Resistance in pounds, days. davs. davs. davs. r after avs. — % 5 10 i5 20 25 h.m. d h. EQ. li/s. lbs. ILis. Ids. Itw. 1 37.75 12.25 200 3 low-red 2 45 1 7 10 a 40 i 357 = 200 5 2 30 3 2 75 7 9.50 10 3 40 | 357 = 200 red 3 5 7 15 4 56.60 18.40 357 = 200 5 highest 5 16 2.75 7 9.50 5 25 13 123 77 red 2 30 7 16 I, 25 13 200 " 2 30 18 3.75 4.75 5.50 7 50 15 357 = 200 « 3 45 18 2 50; 9 11 23 ; 50 357 = 200 " 3 30 15 4 10 17 24 'J 50 1 200 " 2 2 16 2.75! 7 10 11 10 60.90 19.10 160 cc 1 45 1 16 3 6.50 16 28 11 40 200 2 cc 3 4 1 50 5.25 7 8 IS 40 121 77 cc 1 30 4 2.00 13 16 20 13 25 100 cc 2 2 1 3.50 u 25 100 65 " 2 1 12 20 22 15 75.50 24.50 200 it 40 7 15 17.50 16 113.25 36.75 200 " 50 1 30 17 24 17 113.25 36.75 200 CC 30 45 23 26 It 37.75 12 25 2O0 cc 30 30 17 25 19 75.50 24.50 200 " 45 1 6.50 16 2u 40 100 67 cc 48 17 16 16 21 25 100 cc 48 18 3.50 3 ■22 40 100 cc 29 16 21 26 23 119 50 80.50 low-red 4 24 119.50 80.50 led 38 25 119.50 b0.50 highest 30 2b 6 2 114 78 red 23 C 2 27 150 100 cc 2- 100 60 highest - 29 8.10 3.70 100 60 low-red 30 21 4.50 30 8.10 3.70 100 60 red 30 ] 4 2 31 8.10 3.70 J 00 60 highest 20 1 14 5 32 140 100 red 27 33 25 10 140 100 " 27 1 2 34 CO 180 highest 30 14 10 35 75 150 '< 30 1 3 10 36 58 140 cc 20 1 11 37 53.60 46.40 200 cc 30 1 55 21 3= 53.60 46.40 LOO cc 30 14 8 39 50.58 16.42 200 " 30 17 8 40 37.75 32 25 83.00 56.40 cc 30 12 20 41 40 100 cc 30 11 4'2 150 loo red 451 SOLIDIFICATION OF MORTARS. 135 In addition to the above, a series of experi- ments was performed by Lt. Kendrick, with the view of testing the hydraulic virtues of the oxide of manganese, but in no instance, where this substance was mingled with pure lime, did he succeed in obtaining any good result, nor was he more fortunate in substituting pure magnesia in the place of the oxide of manganese ; as appears from the table, Nos. 23, 24, 25, 27, 28, 42. There is a strong presumption, therefore, that neither manganese nor magnesia will of itself impart hydraulic qualities to fat lime. So far as mag- nesia is concerned, this view is opposed to that of Yicat ; but it seems probable, that in those cases mentioned by him, in which he appeared to obtain different results with lime and magnesia, the materials employed were not entirely pure. A single successful experiment, however, with either manganese or magnesia and fat lime, the materials being proved to be pure, will show this inference to be erroneous. The positive results exhibited in the table, are more to be relied on and lead to more safe con- clusions. The examination of them shows : 1st. That silica and lime employed together, without any other admixture, will give a hy- draulic compound. Nos. 3, 8, 9, 11, 13, 34, 35, 36. 2d. That silica, alumina and lime will produce an equally energetic composition. Nos. 1, 4, 6, 7, 16, 37, 3S, 39. In some respects, the addition of alumina improves the mixture. Being inso- luble in water, it protects the outer portions of the lime from solution, until the union of the latter with the silica is effected, and prevents the free permeation of water through the mortar, which might greatly injure its quality. 3d. That silica, alumina and magnesia, will 136 TREATISE ON MORTARS. from a good hydraulic compound, without the addition of lime, Nos. 10, 17, 18, 19. This fact may account for the existence of hy- draulic qualities in the native carbonate of mag- nesia, which, like the carbonate of lime, may frequently contain a portion of clay in its com- position. 4th. That silica, lime and magnesia give a better hydraulic result, than silica and lime, Nos. 11, 12, 13, 14. This probably arises from the formation of double silicates, the silicic acid uniting with both lime and magnesia. Nos. 21, 22, 41, exhibit surprising results, and lead to the inference which is generally deduci- ble from the table, that the induration of hy- draulic mortars is not to be ascribed to any one agent, nor ever to precisely the same causes ; though, in most cases, it is owing to the formation of a silicate. With the view of discovering the constituents of some of our hydraulic limes, I submitted for analysis to Dr. Jackson of Boston, two specimens of limestone, obtained from different localities and possessed of different properties. They both fur- nish after calcination, products, which it is neces- sary to pulverize, in order to prepare them for use, and are both known in commerce, as hydraulic cements; one called Barnes's Connecticut Cement from Southington, Conn., the other, Lawrence's Rosendale Cement, from the vicinity of Rondout, New York. The first was inferior in quality to many hy- draulic limes, although sometimes quite energetic. A portion of the cement being converted into paste and placed in a tumbler of water, cracks invariably showed themselves upon its surface, and being remixed and again immersed, it re- quired from ten days to a fortnight to become SOLIDIFICATION OF MORTARS. 137 hard. The Rosendale cement, on the other hand, was quite energetic, setting under water in five minutes after immersion, though, like the cement from Connecticut, its energy had probably been somewhat impaired, since it had left the kiln. The results of the two analyses were as follows : — One hundred grains of the Connecticut cement, being thoroughly dried at 212° F. yielded on chemical analysis: — 'Siliceous & ferruginous sand, 8.780 grs. Oxygen. Silicic acid, 23.620 12.275) Carbonic acid, 8.000 5.788 > 18.135. Sulphuric acid, 0.137 0.072 ) Lime, 47.285 13.281 5 Alumina, 6.120 2.941 Peroxide of iron, .... 3.260 0-99 8 liaiQn Magnesia, 1.920 0.760 f 10 - lJU - Manganese (oxide of), . . 0.100 0.077 { Potash, 0.792 0.133J 100.014 014 18.190 jain, ashes. 100.000 Oxygen of the acids = 18.135 Oxygen of the bases = 18.190. One hundred grains of the Rosendale cement yielded on analy- sis, as follotcs : — Silicic acid, Sulphuric acid, Carbonic acid, Lime, . . . Magnesia, . . Alumina, . . Peroxide of iron, Oxide of manganese Potash, .... Soda, .... Water 18.170 1.000 4.000 44.970 19.080 5.500 4.900 1.000 673 0.438 0.200 grs. con. Oxygen. 9.439 ) 0.598 > 12.93. 2.893 ) 12.630 7.360 T 2.563 1.501 0.464 i 12.291. 0.114 | 0.112 | 0.177J 99.931 The oxygen of the acids is, 12.930 " " " " lime " 12.630 " " " « other bases is, 12.291 * The sand is not in chemical combination, but is mechanically mixed with the other ingredients of the cement. 12* 138 TREATISE ON MORTARS. From which it would seem that bibasic com- pounds are formed when the cement sets. On comparing the analyses with each other, it appears that the chief constituents of the Con- necticut cement are silica and lime, whereas a large proportion of magnesia enters into the com- position of the Rosendale. The inference sug- gested by the results of the table is thus strength- ened by those of the analyses, viz., that the increased energy of the latter cement may be ascribed to the formation of double silicates. Dr. Jackson, who has performed many experi- ments with hydraulic mixtures, informs me, that the oxide of manganese will answer the same purpose as magnesia : which is not surprising, as the two substances are isomorphous with each other. Professor W. B. Rogers, of the University of Virginia, has analyzed within the last six years upwards of a hundred specimens of cement rocks derived from the carboniferous and Appalachian series of Virginia and other States ; and he believes the cause of the solidification of the products, obtained by calcining both those classes of rocks, to be the formation of silicates : in the former chiefly those of lime and oxide of iron, in the strikingly hydraulic Appalachian limestones, those of lime and magnesia. 209. The following table, extracted from the recently published report of the Geological Survey of New York, will show the composition of various hydraulic limestones of that State. SOLIDIFICATION OF MORTARS. 139 pj «• a SI t^CT' P r* 2Lp- P. -» 3 ° « g O P n tv Is- El do- 33?j •xJOOTj >r| *j ^ o *5 3 S.s-3««j 3 5 >-H a o p-o 5 2.3 2L 3 =•• o I » 3 2. cr < ps -p •"< r- a. ^ m 1 « - c* St g ti- QQ w S g- i T C CO Bt?p &S 1 ,* 3- r .£ K-„.rt o 23 H 30?5 O ? 'T^n p Pon„3 w p CO CJ 4 ( O g O 52 P. ^' o E-ZL 3 y - i^ra So ? IS 9 OB. - PS o uq & =1 o ^ 3 cTO P2^S2 £«> ' ^5 a o >• • 3 c 3 §*».§■ h 2 EC 2 8 5 o cn p 3 c -* s S ^ £ u^ O o w ^ o r> » era- £ MS Xoq cr p 3 0> P CO a cr < 3' o'cq So B.sr O m & P- 3 P- 1 — /. 3 M 3 5" to o I. CO o' F ps U9 3 o en r 1 B o p cV o 3^ CD o CD P 5' o' 3 3 o 3 —1 PX 3 R" BJ 3" pa o 3 Cfl CO. ft „ to CO •" JO ID Ci to Cn 1&. h (0 to h~ CO CO in to o en CO -1 en o o to CO to JO a> CO SI cn ^ o* CO CO t&. ^ CD o b o o o Ol cn o o 4 PS 3 to to to to J - oo pu CO cn en b o o 3 b b o o i? o o o o o ^ p uq v ^ CO iP> "^ h J~* ^ - ^ p ^ in In b SJ CO o o en *. 3 o to CO JO SI cn ID -1 in -4 --J OS b CO o -J o CO o CO o CO to CO ^ J-* >c> 00 o Si 00 Si •-J Id ^» CO cn o Ol o Ci o cn cn • ~^ t~* t_l to CO pl o en to CO * ^ Ci to cn o J!' S| Ol M o p CO to lb. ^r * o ^* I - S| o o >- 01 01 b CO b to Ci o o o o en M to CO i" H J" - J - * CC CO en *. (0 en 00 to bo Ci o o a o M to ib "^r p JO S| 00 r* : o to SI si b til CI o o M to CO ~~^I k v ^ - 09 o> cn SI r OJ ^ >u I* cn p p CI CD H - cn INDEX. Pages. Absorption of carbonic acid and moisture, by limes exposed to the atmosphere, Art. 7, 40, . . . . 2, 20 Acids, action of, on carbonates of lime and magnesia, Art. 15, 25, 5, 11 Adhesiveness of mortars, how estimated, Art. 98 to 101, 55 to 58 Air, deterioration of hydraulic limes by the action of, Art. 40, 20 influence of the contact of, in the manufacture of Pouz- zolana, Art. 69, ....... 36 Arenes, meaning of the term, Art. 59, .... 31 used as a pouzzolana, Art. 59, ..... 31 physical characters of, Art. 60, ..... 32 improved by calcination, Art. 61, .... 32 Argillaceous limestones, kilns for burning, Art. 108 to 121, 62 to 72 B. Bertiiier, M., his method of analyzing limestones, Art. 21, 8 Beton, meaning of the term, Art. 169, .... 106 Bricks, dust of, used as a Pouzzolana, Art. 70, ... 36 number of, stuck together with hydraulic cement and projecting from the 6ide of a wall, Art. 99, . . 56 fragments of, used in making concrete, Art. 170, . 106 Brinel, Mr., his experimental semi-arches, Art. 100, . . 56 C. Calcareous incrustations in using trass, Art. 58, minerals, tests to discover them, Art. 1, 4, 15, Calcination of limestone in the large way, Art. 106, conditions to render it easy, Art. 107, various kilns for, described, Art. 108 to 117, time required for, Art. 115, average quantity of combustibles in, Art. 118, Carbonate of lime, chemical constitution of, Art. 1, of magnesia, value as a cement, Art. 25, 30 1, 2, 5 61 61 72 67 Til 1 11 62 to 142 INDEX. Carbonic acid, of the atmosphere, absorbed by lime, Art. 7, increases the hardness of limes, Art. 204, solidification of mortars attributed to the slow and suc- cessive action of, Art. 205, ...... Cement, hydraulic, improperly called Roman, Art. 42, proof of its excellence, Art. 98 to 103, See Hydraulic Cement. Clays, nature of, Art. Go, . . .... used as pouzzolanas, Art. 66, .... mode of examining and testing qualities of, Art. 67, 68, best kind of, for making artificial lime, Art. 124, Coal, bulk of, used in burning limestone, Art. 118, Composition of mortars, Art. 73 to 90, Concrete, meaning of the term, Art. 169, . materials used in making, Art. 170, principle in fixing proportions for, Art. 171, English mode of preparing, Art. 172, . for foundations of sea-walls, Art. 175 to 182, for foundations of scarp-wall, Art. 183, for pintle blocks, Barbette, Art. 184, for foundations, breast-height walls, Art. 185, for superstructure, sea-wall, Art. 186 to 189, for piers and scarp, Fort Warren, Art. 191, for roofing casemates, Art. 192 to 198, use of shells in, Art. 199, .... foundations in water, Art. 200, economy in using, Art. 202, Pajes. 2 128 . 129 21 55 to 59 33 33 34,35 74 69 38 to 50 106 106 107 107 to 114 114 114 116 16, 117 118 118 to 122 123 124 126 109 D. Dolomites, useful as cements, Art. 23, mode of analyzing by hydration, Art. 24, 10 10 E. Desiccation rapid, bad effects of, upon mortars, Art. 88, . 49 Eddystone lighthouse, mortars used in building, Art. 90, . 51 Extinction. See Slaking, Art. 6, 32 to 38, . . 2, 15 to 18 Forge scales, powdered, used as a pouzzolana, Art. 71, . 36 Fossil sands, deposits of, Art. 48, ..... 24 Foundations, use of concrete in, Art. 175 to 185, 200, 109 to 116, 124 G. Girard, M., remarks upon the arenes, Art. 59, Gravel, how the voids in are measured, Art. 76, 77, Low to ascertain proportions in mixing, Art. 79, 31 41,42 42 INDEX. 143 Greywacke, its character as a pouzzolana, Art. 62, Grouting, meaning of the term, Art. 168, Gypsum, for what purpose used, Art. 26, how distinguished, Art. 27, how tested and prepared, Art. 23, 29, Pajes. 32 105 12 12 13 H. Hardness of mortars, variations in, how tested, Art. 104, Heat of the weather injurious to mortars, Art. Hydrate of lime, chemical compound, Art. 7, Hydraulic cement, properties of, Art. 12, mode of testing, Art. 19, stone to be burned with care, Art. 43, precautions in using, Art. 44 to 47, how to restore the quality of damaged, Art. 45, 123, how to preserve, Art. 46, manufacture of, Art. 121, 122, manufacture of, artificial, Art. 124, 125, Hydraulic lime, properties of, Art. 11, mode of testing, Art. 18, remarks upon, Art. 31, 40, . mode of preserving in the large way, Art. 41, manufacture of artificial, Art. 124, 155, 60 49 2 4 7 21 22 23 22J73 23 71 to 73 74, 75 4 6 15,20 20 74,75 I. Immersion, slaking by, Art. 35, 36, ... 16, 17 Ingredients used in making mortars, Art. 30, ... 14 Iron stone, siftings of, used as a pouzzolana, Art. 71, . . 36 Induration of mortars, Art. 203 to 209, . . . 128 to 138 Jaghery, meaning of the term, Art. 144, 92 K. Kendrick, Lieut., experiments with hydraulic mixtures, Art. 208, . . . 132 Kilns, for burning limestone, comprised under two heads, Art. 108, 63 best form of "flame kiln," Art. 109, 111, . . 63,64 mode of charging " flame kiln,'' Art. 110, ... 63 for burning bricks and lime together, Art. 112, . . 64 adapted to the calcination of artificial pouzzolana, Art. 112, 64 temporary, or " field," Art. 113, .... 65 combination of coke-oven wilh lime kiln, Art. 114, . 65 " perpetual," used in Yorkshire, Art. 116, ... 63 144 INDEX. Kilns, conical, Art. 117, .... manner of charging coal kilns, Art. 118, remarks upon, Art. 119, 120, Pages. 68 69 70,71 Lime, one species only of, Art. 2, 1 substances affording, Art. 3, . . . . . 1, 2 properties of pure, Art. 7, ..... 2 classification of limes, Art. 8, .... 3 "poor" lime, Art. 10, 16, 31, . . . . 4,6,14 "fat" lime, Art. 9, 17, 31, 39, . . . 3,6,14,19 " hydraulic" lime, Art. 11, 18, 31,40, 41, . . 3 to 20 relation between the qualities of limes and the chemical constitution of the stones whence they are derived, Art. 22, 9 three modes of slaking, Art. 32, 35, 37, . . 15 to 17 mode of estimating increase in bulk, Art. 33, . . 16 mode of preserving caustic, Art. 39, 41, . . 19,20 when it is better to err from a deficiency rather than from an excess of, Art. 85, ..... 48 bad qualities of fat improved by the use of sugar, Art. 144, 92 how fat lime may acquire hydraulic properties, Art. 37, 17 impotency of fat on quartz, Art. 75, .... 41 Limestones, chemical constitution of, Art. 1, ... 1 many varieties of, furnishing each a different product, Art. 1,2, 1 mode of distinguishing, Art. 4, 15, . . . . 2, 5 mode of analyzing, Art. 21, ..... 8 calcination of, in the large way, Art. 106 to 120, 61 to 73 magnesian, see Dolomites. Lime-water, action in precipitating magnesia, Art. 21, . 9 M. Magnesia, combines with water, though slowly, Art. 23, . 10 how separated from lime, in an acid solution, Art. 25, 11 Magnesian limestones, see Dolomites. Manganese, oxide of, opinions as to the virtues of hydraulic lime, depending on the presence of, Art. 208, . . 131 Manipulation of mortars, Art. 88, 89, 163, ... 49, 102 Marble, chemical constitution of, Art. 5, 2 Masonry, precautions respecting soaking materials used in, Art. 168, ... 105 Minion, meaning of the term, Art. 71, 36 used as a pouzzolana, ....... 36 Molasses, used to improve the qualities of rich lime, Art. 144, 92 Mortars, ingredients of, Art. 30, 14 choice of mode of slaking lime for, Art. 38, . . 18 INDEX. 145 Fa?es. Mortars, remarks upon, Art. 73, 74, . . . . 38 general principle in the composition of, Art. 75, . 39 minimum of cementing matter required in, Art. 76, . 41 mode of measuring voids in sands for, Art. 76, 77, 41, 42 mode of measuring ingredients of, Art. 80, • • 44 best proportion of cementing matter in, Art. 83, 84, 46, 47 manipulation or manufacture of, Art. 88, 89, 163, 49, 102 used by Smeaton, Art. 90, 51 classification of, Art. 127, 78 for " pointing," Art. 131 to 137, . . . 82 to 87 for " stucco," Art. 138 to 149, . . . . 87 to 95 " ordinary " (fat lime and sand), Art. 150 to 154, 95, 96 implements used at Fort Warren in making, Art. 155, 97 machines for making, described, Art. 156, 157, 97 to 100 at Fort Warren, mode of slaking the lime for, Art. 153, 99 for stone masonry, Art. 160, ..... 101 102 103 104 104 105 for brick masonry, Art. 162, .... manipulation of, Art. 163, ..... cost of, Art. 164, ....... implements for carrying, Art. 165, quantity of, in cubic yards of masonry, Art. 167, application of, Art. 163, ..... solidification of, Art. 203 to 209, . . .128 to 138 Muriatic acid, action of, on limestones, Art. 4, 15, . . 2, 5 N. Nitric acid, action of, on limestones, Art. 4, 15, . . . 2, 5 O. Oxide of calcium, chemical name of lime, Art. 2, . . 1 Oxide of manganese, see Manganese. Parker's hydraulic cement, improperly termed Roman, Art. 42, 21 Pasley, Gen., his modes of determining the strength of mor- tars and cements, Art. 93 to 103, . . . 52 to 59 his process of making artificial cement in the large way, Art. 125, ........ 75 Paste, volume yielded by pure quick lime, Art. 6, . . 2 consistence of, in fixing proportions of ingredients in mortars, Art. 80, .... ... 45 Petot, M., theory of solidification of ordinary mortars, Art. 205, 129 Piers, concrete used in constructing, Art. 191, . . . 118 Pise, arenes used as, Art. 59, ...... 31 Plastering, see Stucco. 13 146 INDEX. Plaster of Paris, see Gypsum. Pointing, definition of, reasons for, Art. 131, mortar for, requisites of, Art. 132, ingredients with their proportions of, Art. 133, 134, preparation and application of, Art. 135 to 137, . Pouzzolanas. meaning of the term, Art. 54, chemical constitution of, Art. 55, not injured by exposure, Art. 55, distinguished into natural and artificial, Art. 56, pouzzolana proper, Art. 57, .... substances comprised under the name of artificial, Art. 04, experiments with clays for making, Art. 67, 68, . influence of the contact of air in the manufacture of, Art. 69, rule in the use of, Art. 85, manufacture of artificial, Art. 126, induration of, mixed with fat lime, Art. 206, Prinsep, Mr., his method of analyzing dolomites, Art. 24, Pumps, use of, in the process of immersing beton, Art. 200, Paget. 82 83 83 84,85 28 29 29 29 29 33 34,35 36 48 76 130 10 125 Q. Quartz, impotency of caustic lime on, Art. 75, Quick lime, how preserved in the large way, Art. 41, 41 20 R. Rammers, used in "laying" concrete, Art. 181, 191, 112,118 Resistance of mortars, how estimated, Art. 92 to 104, 52 to 60 Roman cement, name applied to English, Art. 42, . . 21 Rueble masonry, cost of, at Fort Warren, Art. 202, . . 127 S. Sands, different kinds of, how produced, Art. 48, . . 24 classification of, Art. 49, ...... 24 choice of, for mortars, Art. 50, 25 injured by the presence of earthy matters, Art. 51, . 25 mode of cleaning, in the large way, Art. 52, . . 27 use of, in mortars, Art. 53, ...... 23 that they are inert substances, Art. 75, ... 41 how the voids of are determined, Art. 76, 77, . 41, 42 specific gravity of quartzose, Art. 77, .... 42 object of mixing, Art. 79, 82, . . . . 42 to 46 proportions of, to be used with the different limes, Art. 83 to 87, 46 to 48 employed at Fort Warren, Art. 128, .... 78 vessel there used, for determining voids, Art. 129, . 80 proportion of, in pointing mortar, Art. 133, 134, . 83 INDEX. 147 Pages. Sands, proportion of, in stucco, Art. 145, .... 92 proportion of, in stone and brick mortar, Art. 160, 161, 101 Sea water, employment of, injurious in slaking lime, Art. 38, 19 "Set" or "setting," definition of, Art. 13, ... 5 quickness of set, indication of the goodness of a ce- ment, Art. 19, 8 Shells, afford lime after calcination, Art. 3, ... 2 employed in making beton, Art. 199, . . . 123 Shrinkage of lime, reason for using sands, Art. 53, . . 23 reason for increasing proportion of cementing matter, Art. 83, 46 Silica, its efficacy in a limestone, Art. 22, 208, . . 10, 132 Slag (foundry), used as a pouzzolana in constructing docks at Sunderland, Art. 72, ...... 37 Slaking of lime, defined, Art. 6, ..... . 2 ordinary process of, Art. 32, 34, .... 15, 16 expansion of bulk in, how ascertained, Art. 33, . 16 second process of, Art. 35, 36, ..... 16 third process of, Art. 37, 33, 17 choice of the process of, Art. 38, .... 18 Sheaton, his mode of using pouzzolanas, Art. 85, . . 48 twenty different mortars used by, Art. 90, ... 51 his remark that the hydraulic property of lime was due to the presence of clay r , Art. 208, Smith, Capt., mode of determining voids, Art. 77, Solidification of mortars, theory of, Art. 203 to 209 Solubility of fat lime in water, Art. 9, Stone, its adherence to hydraulic cement, Art. 103, Strength, comparative, of mortars, how estimated, Art. 92 to 104, Stucco, implements used in laying on, Art. 140, . mortar for interior, Art. 141, application of interior, Art. 142, 143, ... 89, 90 the employment of sugar or molasses advantageous when buildings are to be stuccoed with fat lime, Art. 144, for outside work at Fort Warren, Art. 145, mode of preparing surface for, Art. 146, application of exterior, Art. 147, 148, on a surface of concrete, Art. 149, .... Sugar, used to improve the bad qualities of fat limes, Art. 144, 92 Sulphate of lime, or plaster of Paris, not acted upon by acids, Art. 27, 12 123 131 42 to 133 4 59 52 to 60 88 Tar, coal, used to protect temporarily the concrete roofings at Fort Warren, Art. 197, 122 Trass or terras, composition and properties of, Art. 58, . 30 1/ / 148 INDEX. Fajes. Theory of the solidification of mortars, Art. 203 to 209, 128 to 338 Tiles, fragments of, used as an ingredient in making con- crete, Art. 170, 107 Tile dust, used as a pouzzolana, Art. 70, .... 36 Treussart, Gen., mode of estimating the resistance of mor- tars, Art. 94, 95, 53, 54 Totten, Col., mode of estimating the comparative hardness of mortars, Art. 104, 60 V. Vapor, a current of aqueous, facilitates the reduction of lime- stone into lime, Art. 107, ..... 62 Vicat, M., table showing the different rates of expansion of the fat and hydraulic limes in slaking, Art. 38, . 18 \.MV Far Ian. B-LrffoT-3 ^ Los Xit?.-. Ba F '" • <■■> kl I ■:/"■■ m TCThsluri k, • 20 1 ee n n n n n o n n r c r n n n n n n n n n n n c r ii n— n- & ci d| n n n d r r r n r c n r n c r n n ri ////■ calcining slay Implements used by stone cutter in prepari I Implements used by pointing ^ i II, rl.,r Cai I THE LIBRARY UNIVERSITY OF CALIFORNIA Santa Barbara THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW. 707 s Series 9482 .^SOUTHERN REGIONAL LIBRARY | A 000 582 130 1 4