405

B32

RESOLUTIONS

OF THE

ions held at Mil, Dresden, Berlin, and Vienna,

FOR THE

PURPOSE OF ADOPTING UNIFORM METHODS FOR TESTING

CONSTRUCTION MATERIALS WITH REGARD TO

THEIR MECHANICAL PROPERTIES,

J, BAUSCHINGEE,

PROFESSOR IN TH E TECHNICAL H IGH SCHOOL, MUNICH.

TRANSLATED BY

O. M. CARTER,

CAPTAIN, COUPS OK ENGINEERS, U. S. A.,
AND

K. A. GIESELER,

UNITED STATES ASSISTANT ENGINEER.

WASHINGTON:

GOVERNMENT PRINTING OFFICE.

1896.

RESOLUTIONS

OF THE

Cooveofastidtl at Municti, Dresden, Berlin, and Vienna,

FOR THE

PURPOSE OF ADOPTING UNIFORM METHODS FOR TESTING

CONSTRUCTION MATERIALS WITH REGARD TO

THEIR MECHANICAL PROPERTIES,

J, BAUSOHINGEE,

PROFESSOR IN THE TECHNICAL HIGH SCHOOL, MUNICH.

TRANSLATED BY

O. M. CARTER,

CAPTAIN, CORPS OF ENGINEERS, U. S. A.,
AND

E. A. GIESEUER,

UNITED STATES ASSISTANT ENGINEER.

WASHINGTON:

GOVERNMENT PRINTING OFFICE.
189G.

WAK DEPARTMENT
, . . Document No. J.. ,
OJfiwbf the C-kief ef Eh^neers.

UNITED STATES ENGINEER OFFICE,

Savannah, Ga., January 13, 1896.

GENERAL: I have the honor to transmit herewith a translation from
the German of the Resolutions of the Conventions held at Munich,
Dresden, Berlin, and Vienna, for the Purpose of Adopting Uniform
Methods for Testing Construction Materials with Regard to their
Mechanical Properties. The resolutions are of value, and, I think,
should be printed for distribution to the officers of the Corps of
Engineers.

Very respectfully, your obedient servant,

O. M. CARTER,
Captain, Corps of Engineers.
Brig. Gen. WM. P. CRAIGHILL,

Chief of Engineers, U. S. A.

[First indorsement.]

OFFICE CHIEF OF ENGINEERS,

U. S. ARMY,

January 18, 1896.

Respectfully submitted to the Secretary of War, with the recom-
mendation that the work be printed at the Government Printing Office
for the use of the Corps of Engineers, and that 300 copies be obtained
on the usual requisition.

W. P. CRAIGHILL,
Brig. Gen., Chief of Engineers.

[Second indorsement.]

WAR DEPARTMENT,

January 21, 1896.

Approved as recommended by the Chief of Engineers.
By order of the Secretary of War :

JOHN TWEEDALE,

Chief Cleric.

M46822

CONTENTS.

Page-
Introduction _ 7

I. General provisions 11

1. Requirements of testing machines 11

2. Arrangements for mounting test pieces 11

3. Uniform testing machine 11

4. Data concerning machines and methods, to bo given when commu-

nicating results 11

5. Data in regard to test [pieces, to be given when communicating

results , 11,12

6. Limits of exactitude .., 12

7. Influence of time on tests of strength 12

8. Materials should be tested for the class of strains occurring during

actual use 12

9. Impact tests for material subjected to shock when in use 13

10. Standard impact machine 13

II. Tests of wrought iron and steel 16

A. Rails, Nos. 1-6 16

B. Axles, Nos. 1-3 17

C. Tires, Nos. 1-3 17

D. Multiple or piece tests, Nos. 1-3 17

E. Wrought iron for bridges, Nos. 1-3 18

F. Low or mild steel for bridges, Nos. 1-2 18

G. Wrought iron for boiler work, Nos. 1-3 18

II. Low or mild steel for boiler work, Nos. 1-5 18

The place at which, and the manner in which, test pieces should

be cut out of boiler plates 19

I. Wire, Nos. 1-3 20

K. Wire rope, Nos. 1-2 20

L. Measurements to be made in tension tests, Nos. 1-5 21

M. Form of test pieces for tension tests, Nos. 1-7 21

N. Bending tests 23

III. Tests of cast iron, Nos. 1-7 24

IV. Tests of copper, bronze, and other metals 25

V. Tests of wood, Nos. 1-7 26

VI. Tests of shipbuilding materials, Nos. 1-2 28

VII. Tests o f stone 28

A. Stone in general ; resistance to boring or quarrying, Nos. 1-5 28

B. Building stone 30

a. Natural building stone, Nos. 1-11 30

/?. Artificial build ing stone 32

aa. Bricks, Nos. 1-7 32

j8/3. Roofing tiles, Nos. 1-8 34

C. Paving and ballast material, natural and artificial, Nos. 1-11 35

D. Tests of preservatives for natural and artificial stone 36

Page.

VIII. Tests of hydraulic binding media 37

A. General remarks, Nos. 1-2 37

B. Nomenclature, Nos. 1-6 38

C. Tests 38

1. Weight 38

2. Fineness of grain 38

3. Conditions of setting 39

4. Constancy of volume 40

5. Tests of strength 42

6. Adhesive strength 44

7. Density 44

8. Action of sea water on hydraulic binding media 44

New problems 44

INTEODUOTIOISr.

* *
I V

It is universally acknowledged at the present day that tests of mate-
rials of construction with regard to their mechanical properties are com-
parable with one another and give practical results only when they are
made according to uniform methods. The recognition of the necessity
for such uniformity brought about as early as 1876 the adoption of
u Standard rules for furnishing and testing Portland cement" by the
Association of German Portland Cement Manufacturers, also the
"Drafts of specifications for furnishing axles, tires, and rails of iron
and steel" which were recommended in 1879 by the Association of
German Eailway Administrations for adoption by its members. 1

Those first attempts at unifying the methods of testing emanated,
however, from too narrow sources, from manufacturers only on the one
hand and from consumers only on the other, and their suggestions
were naturally governed by their respective interests ; at least this was
asserted to be the case. Each of those agreements, moreover, had the
inconvenience of relating to only a single group of materials; further-
more, they were not confined to methods of testing, but specified con-
ditions to which materials should conform when tested according to
prescribed methods.

The convention held in the autumn of 1884 at Munich, composed of
representatives of all the technical professions, with the aim of unifying
the methods of testing the principal materials of construction, neglect-
ing entirely any classification of those materials, was consequently jus-
tified. That convention succeeded in agreeing upon quite a series of
important questions, while a certain number of others were referred to
a permanent committee, which thoroughly discussed them, first in writ-
ing and then orally, at its two sessions held in Munich on the 21st and
22d of September, 1885, 2 and which finally submitted a report upon the
results of its labors to a second convention, held in Dresden on the 20th
and 21st of September, 1886.

The latter convention accepted almost all of the propositions which

! The properties of iron and steel. Seventh supplementary volume to "Organ fur
die Fortschritte des Eisenbahnwesens." Wiesbaden, 1880.

2 A detailed report 011 the discussions of the Munich convention and the perma-
nent committee appointed by it is contained in No. XIV of "Mittheilungen aus
dem mechanisch-technischen Laboratorium der technischen Hochschule/' Muenchen.
(Munich, Th. Ackcrmann.)

were submitted to it, but charged a second permanent committee with
the study of a series of questions which had not yet been taken hold of or
agreed upon, with instructions to render a report to a third convention,
which was to meet on the 19th and 20th of September, 1890, in Berlin.
At that convention resolutions were adopted with regard to a certain
-number of propositions, while others, together with certain new ques-
tions, wore r&ferrexlto a third permanent committee, charged with pre-
;.. n$ing.a.:?epprt>to a fourth convention, which was to be held at Vienna
oil th'e24th ab4'25th of May, 1893. At that convention an agreeme.it
was reached again 011 only a portion of the proposed resolutions, and
the others were referred, with a great number of new questions, to a
fourth permanent committee, the executive of which was at the same
time charged with the preparation of a memoir containing all of the
resolutions adopted up to that date, as well as all of the questions upon
which no agreement had been reached, in the same way as had been
done for the first two conventions in a pamphlet entitled "Resolutions
of the Conventions held at Munich and Dresden," etc.

The hope expressed in that pamphlet that its publication might aid in
sustaining tbe eiforts already put forth, and at the same time induce those
who, up to that date, had not interested themselves in such questions
to participate in the future, has been fulfilled in a very gratifying way.
Not only has there been an increase in the number of delegates from
countries already represented (Germany, Austria-Hungary, Switzer-
land, Russia), but delegates have come from other countries (France,
America, Norway, Holland, Italy, Spain), so that the conventions have
assumed a truly international character. With the aim of developing
this movement still more it should be remembered that each conference
is a reunion at which all members can exchange freely their opinions
as to the best methods to be employed for testing as to its mechanical
properties a certain material intended for a certain purpose. Votes
and resolutions have no other aim than to bring out the methods of
testing which the majority of the members prefer. In conformity with
the first resolution of the first conference, " deliberations are to be
free and resolutions not obligatory." There is nothing to prevent a
question which has been acted upon in a preceding conference from
being taken up again, discussed, and submitted to a new vote. The
methods of testing can not remain unchangeable; they must progress
with our knowledge of the properties of the materials that we employ,
with the improvements brought about in the production of those
materials, with the employment of new materials, etc. It is then neces-
sary that those who are occupied with tests of construction materials
whether from a scientific point of view or because they are making or
using such materials should meet from time to time to exchange
opinions, to mutually instruct one another, and from such deliberations
to agree upon methods of testing that they judge to be the best, or at
least that the majority among them find to be the most suitable for the
time being.

Present methods of communication Lave so nearly eliminated the
dividing- line between all civilized and manufacturing countries that
the unification of methods of testing will have little value if it is limited
to a few countries. The recognition of the necessity for international
agreement has led the conferences, which were participated in at the
beginning only by Germany and some immediately neighboring coun-
tries, to become more and more international in character.

By a decree of the 9th of November, 1891, the President of the French
Republic created a u Commission des methodes d'essai des materiaux
de construction," whose object, as its name indicates, is the same as
that of the conventions of Munich, Dresden, Berlin, and Vienna, and
their permanent committees. Such national institutions have cer-
tainly two great advantages; they have, at least at home, greater
authority and it is easier for them than for private societies to procure
funds for necessary experimental research. It is evident that they lack
an international character, but that could be obtained by a suitable
agreement between the different national commissions; but then the
advantages before mentioned resulting from the private character of
those conferences would be lost. On the other hand, the advantages
resulting from governmental support could very well be combined with
those inherent in conventions such as have been held up to the present,
if the permanent committees, working in the interval between the ses-
sions of the conventions, were composed as well of representatives of
private industry as of technical government delegates and delegates
from technical associations and societies.

To effect those aims the president of the fourth permanent committee
elected by the convention at Vienna was instructed to make every
effort in order that the greatest possible number of technical associa
tions and societies should send delegates who would thus participate
in the labors of the committee.

In the following compendium the resolutions passed so far are printed in ordinary
ronian type; a short statement of the reasons for their adoption is printed in small
roman type, and questions still open to discussion are printed in italics.

UNIFORM METHODS FOR TESTING CONSTRUCTION
MATERIALS WITH REGARD TO THEIR MECHANICAL
PROPERTIES.

I. GENERAL PROVISIONS.

1. All machines for testing materials should be arranged in such a
way that their adjustment can be verified with ease and certainty.

Their construction must be such that with proper handling sudden,
shock-like action of the load is excluded as much as possible. Machines
acting by hydraulic pressure, as well as those acting by means of a
screw, conform to this condition. For practical purposes no separate
attachment making the machine self-acting is required.

2. The arrangement for securing the test piece in the machine must
be such as to allow as much as possible uniform distribution of strain
in the cross section.

To obtain this the following is required:

(a) For pressure tests

(a) One of the two pressure plates must move easily and freely in
all directions.

(I) The pressure surfaces of the test pieces must be as nearly plane
and parallel as possible, and with this object in view should be planed
or turned whenever the material admits of either of those operations.

(/?) For tensile tests

There shall be freedom and ease of movement for adjustment of posi-
tion at commencement of tension. Experience shows that this con-
dition is obtained: In the case of round bars, by means of spherical
bearings; in the case of flat bars, by means of slot and bolt (one slot
and one bolt on each side), or milled ends and corresponding wedges.

Serrated wedges that cut into the test pieces should never be used.

3. It is impossible to recommend for practical use a uniform appara-
tus for tests of strength; it may be stated, however, that a number of
well-known machines are more or less well adapted for their particular
purposes.

4. In communicating results of tests there should be given such data
in regard to the machines and methods employed as are required to
enable one to judge of the value of the tests.

5. Whenever possible, results of tests should be accompanied by
information as to whence the test piece came, by a microscopical or
a chemical examination, or both, by data relating to the manner of
its manufacture, and other known physical, chemical, or technical
properties.

In the case of tests intended mainly for practical purposes it will rarely be prac-
ticable to include sucb complementary information ; still, for the sake of comprehen-
sive results, its acquisition is always desirable, and it should never be neglected in
the case of scientific investigations.

6. Regarding the required degree of exactitude of testing machines
and of the results of tests of materials, the following should be
observed :

(a) To economize time, the limit of exactitude in measuring changes
of force and of form should not be extended beyond the limit of un-
avoidable errors and of imperfection of materials.

(b) In scientific experiments it is obvious that the highest possible
degree of precision should be sought.

(c) In publishing results of tests the degree of precision attained
should be given, or data should be furnished from which an opinion in
regard to it can be formed.

Present experience justifies the following proposition:

(d) In the case of metals when test bars of standard dimensions are
used (such as are described below under II M and under IV) the fol-
lowing degrees of exactitude are sufficient: Strains, at the limit of
rupture, should be measured to tenths of a kilogram per square
millimeter; elongation at rupture should be measured to tenths of 1
per cent; reduction of cross-sectional area should be measured to the
nearest full per cent.

In figures given according to this schedule the last digit is generally
unreliable; consequently it is useless to add any further decimals. In
order to conform as far as practicable to the above degrees of exacti-
tude, length and cross-sectional dimensions should be determined to
tenths of millimeters.

7. According to Fischer and Hartig, time exercises an undoubted
influence on tests ot strength; still other experiments made since then
have demonstrated that there is not at present any sufficient reason to
warrant a demand for any fixed velocity of stretching in testing the
principal materials of construction, viz, iron in all its forms, copper and
bronze (see Bauschinger's experiments in No. 20 of his u Mittheiluugen,
etc.").

8. Materials should be tested for that class of strains to which they
will be statically subjected in actual use.

The quality of a material per se is the sum of its mechanical properties. So long as
we are ignorant of the relations existing between these, and, therefore, are unable
to judge from one or more of them as to the nature of the rest which we are far
from being able to do at present so long will it remain impossible to foretell the
behavior of a material under different conditions of strain, merely from a determi-
nation of one or several of its properties, and so long will it therefore remain
necessary to test materials in regard to the mechanical properties required in actual
use. 1

J For an ample demonstration of this resolution, see "Mittheilungen," etc., No. 14,
pp. 156-160.

9. All materials which will be submitted to shocks when in actual
use should be tested by impact, in order to study fully their qualities.

10. Tests by impact should be made by a standard impact testing-
machine, to be constructed as follows:

(a) It is not considered necessary to prescribe the complete construc-
tion of a standard impact-testing machine, but merely to give accurate
instructions in regard to all of those parts which can possibly exercise
any influence on the results of tests. It is recommended that the
frame of the machine should be made of iron.

It was thought necessary to take into consideration existing apparatus, the essen-
tial parts of most of which conform to the following requirements :

(b) Every standard impact testing machine should be officially
gauged.

It is not impossible that a machine constructed with the greatest care may give
false results on account of unforeseen influences.

(c) Iii accordance with the requirements of German railway admin-
istrations, and considering that impact testing machines should be
housed, the normal weight of hammer should be 1,000 kilograms, 500
kilograms being allowed in exceptional cases.

(d) The hammer may be made of cast iron, of cast or of wrought steel;
its form should be such as to have the center of gravity as low down as
possible. The face of the hammer should be made of wrought steel and
secured by means of dovetail and wedges, ex-
actly centrally to its vertical axis. The fact

that this requirement has been complied with
should be indicated by special marks. The
center of gravity of the hammer must coincide
with the center line of the leads. This line
should be indicated by special marks on the
anvil or the anvil block. '*" Fia

(e) The guided length of hammer should

be more than twice the clear width between guides. The leads should
be made of metal, for instance of railroad iron, the hammer being allowed
but little play between them. Lubrication of the leads with plumbago
is recommended.

(/) Shock machines must be provided with an apparatus allowing
the hammer to be set securely at the desired height. The detaching
apparatus ought not to produce any wedging of the hammer in the
guides; therefore the part carrying the detaching apparatus should be
well guided. The point of suspension should be on the same vertical
as the center of gravity of the hammer, and there should be placed
between the detaching device and the hammer a flexible piece of short
length, for example a chain or a cord. The detaching device officially
prescribed in Eussia and represented by the sketch herewith (fig. 1) is
to be recommended.

(g) With a constant height of fall an automatic detaching device is
recommended.

(7i) The bearings for the test pieces should be attached rigidly to the
anvil block for instance, by the aid of wedges.

The bearing blocks should be made to form as nearly as possible one single mass
with the anvil block.

(i) The weight of the anvil block should be at least equal to ten times
that of the hammer.

Since comparative tests which have been made with a ballistic apparatus and an
ordinary hammer have proved that with an anvil mass four times heavier than the
hammer the results are sufficiently concordant (see Kick on the Law of Proportional
Resistances), one may be sure that with a total anvil mass ten times heavier than
the striking hammer the results will always be comparable with one another.

(k) The foundations should not be elastic; they should be built of
solid masonry and have dimensions determined by the nature of the
ground.

(?) The striking surface of the hammer should always be plane; there-
fore, in testing rails, axles, and tires use should be made of interposed
pieces dressed to the required shape and having plane upper surfaces.
The interposed pieces should be as light as possible.

The same hammer with plane striking surface is recommended in all cases, for the
sake of simplicity of preparation as well as in consideration of the correction of
hammer weight according to o and p.

(m) The results of previous experiments are not conclusive enough
to determine the form of the supports and of the pieces destined to
receive the shock or blow. It is recommended, however, that there
should be given in reports of tests, or when exhibiting tested samples,
exact information regarding the forms employed.

(n) More confidence can be placed in machines whose height of fall
is not greater than 6 meters than in those with a greater height of fall.
It is recommended, therefore, that that height should not be exceeded
in new constructions. Where a stronger blow is desired, a hammer
weighing 1,000 kilograms should be employed.

Machines with a height of fall of 6 meters can bo housed easier and can be con-
structed with more reliability than higher ones. Their parts are also less susceptible
of being disarranged.

(o) The impact work produced by the hammer is the product of its
effective weight by its height of fall. Its total weight should be regu-
lated so that its effective weight amounts to some round figure for
instance, 500 kilograms.

The results are comparable with one another only when the loss of living force due
to friction is eliminated.

(p] To determine the effective weight of the hammer, the following
methods are employed :

(a) A spring balance is placed between the hammer and its lifting
rope, and the effective weight is read during slow descent; there is
thus obtained the weight of the hammer less the friction. The upward
movement furnishes the same weight augmented by the friction.

(ft) The weight of the hammer can be deduced also from the effect
produced, with a given height of fall, on a centrally mounted standard
cylinder, made of best stay-bolt copper, of a shape and weight still to
be determined.

(q) These standard cylinders should also be used to compare impact
machines with one another and to gauge them.

The Mechanical Testing Institute at Charlottenburg has already made such com-
parative tests, and no doubt will willingly take charge of others if it is requested so
to do.

(r) Impact machines which have a work due to friction greater than 2
per cent of their useful work should be rejected.

In order to have conclusive shock tests there should be employed only faultless
machines ; those that are badly constructed or badly kept up must not be used.

(*) The standard impact testing machine is destined principally for
the testing of whole pieces, such as rails, axles, tires, springs, etc.

The testing of pieces specially prepared for shock trials is certainly of great inter-
est, but principally of a scientific one only, and therefore it is not considered, neces-
sary at present to give rules for the construction of a special small impact machine
and for the methods of conducting such tests.

(t) The vertical position of the guides and the proper location of the
hammer between the guides should be rigorously controlled. The ver-
tical projection of the center of gravity of the hammer on the anvil's
surface should be marked on the anvil, and whether the test piece is
properly placed in the vertical of the center of gravity of the hammer,
and whether its placing may not cause pinching or torsional deforma-
tion should be verified previous to every blow.

(u) The work done by a hammer within very wide limits depending
only on the product of its fall by its effective weight, and not on one of
those factors individually, it is recommended that the metric ton should
be taken as the unit and that such an arrangement should be made as
will insure the product always being a multiple of 500. Instead of
graduating the divisions on the scale to meters they will be divided
into metric half tons.

(v) It is recommended that sliding scales should be used in order that
the zero of the graduation may always be set according to the height of
the test piece.

(w) The determination within a millimeter of the deflection by impact
of test pieces resting on supports from 1 to 1 meters apart, is so far
considered sufficiently exact.

(x) To facilitate comparison of the results, it is recommended that
all particulars of the tests should be given for example, the order in
which the blows of the hammer were given, whether there was any
interruption of the test, and whether the test pieces were reversed or
not, also all the phenomena observed during the test.

(y) The permanent commission should study the new propositions con-
cerning the construction of impact machines and talce especial pains to col-

lect the results of all experiments made in regard to the conduct of impact
tests, in order to utilize them for devising a uniform method of testing.

A drawing of an impact machine designed by Engineer Schmitz of
Vienna and fulfilling all of the above conditions has been referred to
the committee for its further study.

II. TESTS OF WROUGHT IRON 1 AND STEEL.
A. RAILS.

1. Rails, for reasons of safety and in accordance with the resolution
under Heading I, No. 9, should be tested by the shock method by means
of suitable technical devices. (Standard impact machines; see I,
No. 10.)

2. If further information concerning the naiure of the metal is desired
tension tests will be made.

3. Finally, rails should be subjected to transverse tests by a static
load, and in two ways; up to permanent set in order to determine the
elasticity, and by means of heavy loads beyond the limit of elasticity
in order to determine the greatest permanent deflection.

Members of the Munich convention have nearly unanimously recognized that for
rails tension tests alone are not conclusive enough. Professor Tetmajer has given
plain evidence of this in mentioning contradictions which have been found on Fin-
nish, Swiss, and French railways between the results of tension tests and the results
obtained in service. Those contradictions arise from the fact that in the first place
rails in actual service are strained by shock, and in the second place that the tension
test relates only to a small part of the cross section ; there is, therefore, reason for
attaching more importance to shock and transverse tests, provided they are made
with well-designed apparatus, the shock tests especially being made by means of
standard impact testing machines; but as those tests do not furnish as many indica-
tions concerning the nature of the metal as do tension tests, especially when the
latter are supplemented by chemical analysis, there is reason to maintain that ten-
sion tests should be employed as long as their deductions may be useful, which will
probably be the case for a long time.

4. Tension tests should be made on pieces rectangular in section and
taken from the exterior fibers of the rail.

One cause of doubt regarding the results of tension tests arises from the fact that
up to the present the round bars used for the tests were taken from the center of
the head of the rail so that the libers subjected to the greatest strains, that is, the
exterior ones the ones located at the wearing surface and at the seat of the rail
were not submitted to the test. But in the case of cast steel, these are the very
parts containing the dangerous blowholes due to silica, which always gather near
the surface of the ingots. It should be remarked, on the other hand, that in the
interior of ingots of pure manganese steel there is a /one of blowholes which may
have an unfavorable influence on the tension test, but not on the rail itself, and
which may therefore give rise to erroneous conclusions. *

1 The term " wrought iron " is here used as distinguished from " cast iron," and is
intended to comprise "'wrought iron" proper and "mild steel."

2 For details see " Mittheilungen der Eidgenossicheii Festigkeitsaustalt," No. 3,
pp. 42-53.

5. The search for methods of test suitable for determining the wear
on rails and tires resolves itself into a search for methods suitable for
determining the resistance to wear. At all events it is certain

(a) That the resistance to wear can not be determined by an experi-
mental process.

(6) That the test of the resistance to wear should be made under con-
ditions approaching as closely as possible those to which the metal will
be subjected during service.

On account of its difficulty this question is for the present set aside.

6. The investigation relative to the influence of different kinds of
tires on the wear of rails should be considered as a special study per-
taining to the administration of railroads.

B. AXLES.

1. The ends, as well as the bodies, of axles should be subjected to
shock tests.

2. When further information regarding the nature of a material is
desired tension tests should also be made.

3. Axles need not be subjected to transverse tests.

C. TIKES.

1. Tires should be submitted to shock tests in the same manner as
axles and rails.

2. Tension tests should be made if, as above, further information in
regard to the nature of the material is desired.

3. The hammering test is not necessary.

D. MULTIPLE OR PIECE TESTS.

1. There should be collected as much information as possible for the
purpose of devising standard rules for multiple or piece tests (test of each
piece in a lot).

2. In deciding upon standard rules for impact testing machines and
machines for tests of strength there should be kept in view the possibility
of making multiple or piece tests.

3. Not only axles should be thought of in this connection, but all con-
struction material of steel and iron.

The multiple or piece test, whicli consists in testing rapidly by a single shock, for
example, each piece of a lot, in such a way as not to injure it, certainly offers more
of a guaranty than that which consists in testing so many per cent of the pieces of
a lot. It has been adopted for a long time for springs, chains, pipes, steam pipes,
boiler tubes, etc. It has given good results in Austria, where it has been used in a
number of cases for axles. It must, however, be recognized that that method otters
great difficulties for the buyer as well as for the seller, but those difficulties can be
overcome by the study and adoption in practice of a well-suited mode of test. The
only experience available so far in regard to multiple testa has been gathered at
Witkowitz, with axles only, and has lately led to abandoning this method of test.
It is desired, however, that more experience should be gathered.
10389 2

E. WROUGHT IKON FOR BRIDGES.

1. Wrought iron entering into the construction of bridges should be
submitted to tension tests, and also

2. To bending tests, both hot and cold, over a mandril 25 mm. in
diameter, by means of a slowly working mechanical contrivance.

The exact conditions that this contrivance should fulfill are given
hereafter under N.

3. Those two tests being sufficient, there is no necessity of making
tests for flattening and rupture.

F. Low OR MILD STEEL FOR BRIDGES.

1. Low steel entering into the construction of bridges should be
submitted, like wrought iron, to tension tests.

2. It should also be submitted to bending tests, both hot and cold,
over a mandril 25 mm. in diameter, by means of a slowly working
mechanical contrivance.

G. WROUGHT IRON FOR BOILER WORK.

1. The portions of boilers composed of wrought iron should be sub-
mitted to the following tests:

(a) For plates:

(1) Tension test.

(2) Bending test.

(3) Forging and punching test.
(&) For angle irons:

(1) Tension test.

(2) Bending test.

(3) Forging and punching test.
(c) For rivet iron :

(1) Tension test.

(2) Forging and bending test.

2. The welding test for angle iron is not absolutely necessary, but it
is desirable.

3. Hot shortness (rupture while hot), which would be shown by it,
is also demonstrated by the hot bending test.

H. Low OR MILD STEEL FOR BOILER WORK.

Wherever bars and plates of mild steel (Bessemer, Martin, or Thomas)
take the place of wrought iron in the construction of boilers they
should be submitted to the following tests :

1. Tension tests.

2. Gold and red-hot bending tests. The edges of test pieces should
be chamfered ; if plates are more than 6 mm. thick, the bending should
be done around a mandrel 25 mm. in diameter, by means of a slowly
working mechanical contrivance, and up to the limit of a given angle.

This test furnishes ail example of how the material will behave when Avorked
into a boiler. A mandrel 25 mm. in diameter is handy, and conforms to the direction
most commonly followed at present.

3. Beudiiig tests after tempering. The test pieces, which are cham-
feied along their edges, should be heated uniformly throughout their
entire length to a cherry red (550 to 650 C.), then quenched in water
of about 25 C., and then bent according to the instructions given
under 2, above.

Experience has shown that there should be employed for boilers onry such mild
steel as is but little hardened by quenching and readily worked after it. Mild
steel, having a resistance of from 38 to 42 kilograms per square millimeter, and 20
per cent elongation, generally fulfills this condition, but it is, however, prudent to
submit it to the above bending tests after having tempered it.

4. Forging tests that is to say, flattening out while red hot. The
test for punching is useless, because the punching of holes in plates of
mild steel should be avoided, on account of the resulting fissures.

5. It is recommended that those establishments which employ mild
steel in practice should make also tests for its welding properties.

Against the general introduction of the welding test there may be urged above all
its difficulty, the dependence of its success upon the skill and experience of the
workmen, and finally the fact that, while rnild steel can be welded, riveting is safer.
It is true that corrugated and rolled plates of the Fox patent, fire tubes and gas
tubes of mild steel, are welded, but all of those pieces are tested individually (multi-
ple test). Again, weldable mild steel either can not be tempered at all, or at least
not readily tempered, and is less sensitive to temperature, but all of this is deter-
mined already by the bending test when tempered.

Tests of plates of annealed mild steel are unnecessary. The following are the
reasons against such tests : On account of the cost, plate iron is not always annealed.
Only in the case of small diameters is rolling done Avhilo hot. In hand Hanging the
plates are heated only locally. Pitted heads are no longer annealed, because annealing
distorts them. The presence of strains in the metal can not be determined by that test.

During the process of annealing it is not only difficult to determine the tempera-
ture, which is of so much importance, but also the time of its action. Measure-
ments of temperature would complicate tests A^ery much. Finally, the real issue
always is to determine the nature of the material in the condition that it is delivered.

In favor of tests after annealing, there may he mentioned, firstly, on account of
interior strains which exist in plates of mild steel, comparative results can be obtained
only when they are annealed ; secondly, the . same material when rolled into plates
of different thicknesses gives different results, and, finally, comparative tests made
of annealed plates and of plates not annealed permit a study to be made of the
defects that result from a lack of care in their manufacture.

The following should be observed in regard to

THE PLACE AT WHICH AND THE MANNEK IN WHICH TEST
PIECES SHOULD BE CUT OUT OF BOILEE PLATES,

notably in the case of plates that have already seen service :

A. PLANE PLATES, NOT WORKED.

In the case of plates with trimmed edges test strips for longitudinal and
trans verse bars will be taken from the edges,and in the case of untrimmed
plates at least 30 mm. inside of the edges. The cutting of the strips may

be done either by means of shears or by sawing. Test strips cut from
bridge plates by means of shears must be straightened out cold under
pressure, or with wooden, copper, or leaden hammers; before dressing
them for tensile tests 5 mm. must be planed off on each side to remove
the traces of the shear cut; test strips cut from boiler plates by means
of shears will be treated in the same way. They will be annealed only
when especially desired.

U. PLATES WORKED ENTIRELY OR PARTIALLY, AND PLATES THAT HAVE BEEN

ALREADY IN USE.

(1) When the properties of the plate, before it was worked, are to be determined.

In this case, pieces out of which the test strips are to be cut should
be taken from the parts having uniform thickness and, as far as pos-
sible, plane surfaces.

If only a curved piece of plate can be obtained, then this will be
prepared by drilling and chiselling, or by means of the circular saw;
the test strips will be cut out of this piece in the same manner. From
plane pieces of plate, the test strips may be cut by means of shears, and
will then be treated as described above.

The curved test strips will be cautiously straightened under pressure,
or with wooden, copper, or leaden hammers, or with iron hammers by
interposing pieces of wood.

(2) When the mechanical properties of the plate, after having been worked, are
to be determined.

In this case it is impossible to give general rules either for the place
from which or for the manner in which the test strips are to be cut.
The principles according to which test pieces are cut out in the above-
described cases will be considered as much as practicable.

J. WIRE.
Wire should be subjected

1. To the tensile test.

2. To the torsion test, by means of machines excluding arbitrary
working.

3. To the bending test, by repeated bending to and fro with machinery
around a mandrel of 5 mm. diameter.

The use of a mandrel with a given diameter suppresses the bad method of clamping
wire and bending it to and fro in a vise with sharp edged jaws.

The permanent committee has been requested to submit a report at the
next convention on a new apparatus used in America for testing wire and
described by Mr. Henning, of New York, at tJtc conference of Vienna.

K. WIRE EOPE.

Wire rope should be tested

1. By tension.

2. By shock or impact, longitudinally.

The bending test is valuable only when it is of long duration, but that is difficult
to obtain in practice, and is, moreover, snperiluons, since each wire in the rope has
already been tested by bending.

L. MEASUREMENTS TO BE MADE DURING TENSION TESTS.

1. During tension tests there should be measured
(a) The tensile strength.

(/>) The reduction of cross section at the point of rupture.

(d) The limit of elasticity or of proportional elongation.

2. It is recommended that there should be obtained as many individ-
ual results as possible for the construction of the work diagram, unless
the same is traced by special apparatus.

3. In obtaining the diagram, special importance must be attached to
the determination of the velocity with which it was traced.

4. In obtaining work diagrams the five following points should be
determined as exactly as possible :

(a) Limit of proportional elongation, or of elasticity.

(b) Yield point.

(d) Maximum load (fall of lever).

(e) Limit of rupture.

5. The area of the diagram must be calculated up to the limit of
rupture.

Practically, only that work is of importance which is done by the entire bar up
to the beginning of contraction. From that instant the principal work is done by
the contracting portion only ; but in the case of most materials of construction such
work is inconsiderable, so that no appreciable error is caused by determining the
area of diagram to the point of rupture. It appears, therefore, advisable to continue
this for the present, all the more as it is difficult to determine the moment of maxi-
mum load. Besides, it is desirable to take account of the portion of the diagram
corresponding to the event of contraction, because there may be relations between
the local elongation produced after the commencement of contraction and the work
required for it.

M. FORM OF TEST PIECES FOR TENSION TESTS.

1. Round bars for tests will be made in four types, viz, with diame-
ters respectively of 10, 15, 20, and 23 mm., according to the require-
ments and possibilities. The length of the cylindrical part, the
so called "actual length," should at each end exceed by at least 10 mm.
the "test length," viz, the length on which the elongation is to be
measured. In order that the percentage of elongation may be inde-
pendent of the form and dimensions of the cross section, the test length,
?, should be made proportional to the square root of the cross-sectional
area, /. On the basis of the internationally adopted bar of 20 mm.
diameter, 200 mm. test, and 220 mm. actual length, this renders

I = 11.3 Vf~

The elongation should be measured on two diametrically opposite
sides of the bar, on each of the broken sections from the initial points
of the test length to the point of rupture and the mean taken of each
pair of measurements.

When rupture takes place outside the middle third of the test length,
that test should be rejected, or a process like the following must be
applied, which, however, presupposes that there is marked on the bar
not only its actual and its test length, but also a graduation to centi-
meters :

Let us suppose that in the case of the bar shown in fig. 2 the rupture
occurs between the fourth and the fifth graduation lines; then starting
from the point of rupture, the graduation lines are marked as shown in
the figure. To the left we now measure from 1 to 5 or from 1 to 10, accord-
ing to whether the elongation of 10 cm. or of 20 cm. is to be determined;
in each case the length 0-b and b-1 must also be measured. To the
right we can only measure from to 3, and to this has to be added the
piece corresponding to the missing one on the left side that is, 3-5 if
the elongation of 10 cm., and 3-10 if the elongation of 20 cm. is to be

IS 14 13 12 II 10 9 8 7 6 S 4 3 2 I

19 IB 17 16 15 14 13 12 II 10 9 6 7 65 432 I

FlO. 2.

determined. In this way the measurement of the bar is accomplished
very nearly as if the rupture had taken place in the middle of the
specimen. The above-mentioned graduation and the method of meas-
urement herein described must both be made on the two opposite sides
of the bar.

2. The actual and the test length of bars with rectangular section
depends on the area of the transverse section and should be computed,
as in the case of round bars, according to the formula:

Test length=Z=11.3 Vf

Likewise, the graduation of the bars and the method of measuring the
elongation after rupture is the same here as in the case of round bars.
It is recommended that the elongation of bars with rectangular section
should be measured on the two narrow sides as well as on one of the
wide sides, and that there should be given separately the mean of the
first two measurements and the result of the last- mentioned one.

3. If the width and thickness of the test pieces with rectangular sec-
tion can be chosen at will, there should be given for the width 30 mm.
and for the thickness 10 mm., and we should consider in general a sec-
tion of 30 bv 10 mm. as normal.

In the place of the old width of bars of 50 mm. the width of 30 mm. will be exclu-
sively adopted, principally 011 account of the small testing machines used in smelt-
ing works, the power of which in most cases does not exceed 50 tons.

4. When thickness of material is given, as in the case of plates, then
for a thickness not exceeding 24 mm. there will be adopted for the test
pieces a width of 30 mm. From 25 mm. upward in thickness, thickness
will be taken as width, and there will be given to the test piece a thick-
ness of 10 mm.

In order not to lose in the last-named case the skin of the metal,
additional thickness will be given at the ends for the formation of the
bar heads for mounting.

When the machines are not powerful enough, the above limits of 24
and 25 mm. may be replaced in exceptional cases by the limits of 16 and
17 mm.

5. In flat iron, angle iron, T iron, channel iron, I beams, etc., test
pieces of 30 mm. in width as the maximum will be cut in the direction
of the length. In the case of great width of the flat iron, or of the

100 t

FIG. 3.

legs of the angle iron, or of the flanges and webs of I beams and chan-
nel irons, test bars will be cut out in successive lengths, as shown in
fig. 3, so that the entire cross section may be considered in the test.

G. The skin of the metal resulting from rolling must invariably be
preserved on the test pieces.

M". BENDma TESTS.

1. The slow- working mechanical contrivance by means of which bend-
ing tests will be made (see above, under Heading E) should fulfill the
following conditions:

It may either act by central pressure between two supports or by
lateral pressure on one of the ends of the specimen, the other being
held by the clamp. The apparatus should be simple and capable of
working rapidly. The part w,here the most strain takes place in the
test specimen should be clearly visible. The bending should take
place in a continuous way, and when it is done around a mandrel the
diameter of such mandrel should be as small as possible.

The test piece should have a rectangular section, the width of which
should be to the thickness as 3 to 1. The edges should be slightly

rounded off. For rivet iron and square iron the cross section will
remain unchanged.

The red-hot test should be made as quickly as possible. In cold-
bending tests the rapidity is not important.

The angle of bending is not in itself sufficient to determine the defor-
mation of the test piece. One must also take into account the radius
of curvature on the convex side, which may be determined either directly
by means of templets or indirectly by measuring the elongation on the
tension face.

The permanent committee has been requested to devise the most suitable
and simple method of measurement. It has also been requested to study
the question of bending tests with injured specimens.

The permanent committee has, besides, been instructed to make an inves-
tigation into the causes of irregularities in the behavior of mild steel,
which often manifest themselves by unforeseen ruptures, etc., although
samples taken from the ends of ruptured bars, on being subjected to an
examination of quality, are found to be perfectly normal. Administration
authorities, etc., are requested, when a case presents itself, to place the
material at the disposal of the committee, in order that, together with an
exhaustive examination, its chemical composition may also be considered.

III. TESTS OF OAST IEOK

1. Test pieces of cast iron should have the form of prismatic bars of
110 cm. actual and 100 cm. test length and a cross section 3 cm. square.
They should be provided with an extension 25 by 25 mm. in cross sec-
tion, from which there can be cut, if it is deemed necessary, cubes 25
mm. high for compression tests.

Greater dimensions would be preferable for transverse as well as for tension tests,
but for the sake of conforming to Wacliler's fundamental experiments the dimen-
sions adopted by him have been retained.

2. The test pieces should be cast in a mold inclined 10 cm. per meter.

Wachlers test bars were cast vertical (it is not stated whether from the top or
bottom), but it has been noticed with some kinds of cast iron that castings become
too cold when they are cast from the bottom, and there is lacking experience in cast-
ing them from the top. The manner of casting also depends on the nature of the
cast iron, on the skill of the molders, foundry men, etc.

3. The height of pressure, measured by the height of the runner
stick, will be 20 cm.

4. Casting is done in dry sand molds.

5. There will be determined by the test

(a) The resistance to flexure up to the point of rupture and the cor-
responding work on three pieces.

(b) The tensile strength of round bars 20 mm. in diameter and 200
mm. in test length, made out of the broken parts obtained from the
test under a, two to be made out of each of the three bars tested there.

(c) The compressive strength of cubes 3 cm. (2.5 cm.) length of edge,
also made out of the broken parts obtained from the test under a, two

to be made and tested out of each of the three bars tested there. The
pressure will be applied in the direction of the length of the original
test piece.

G. The faces of the test pieces for flexure and for compression will
retain the skin, as coming from the mold.

7. Special castings, such as supports of bridges, pipe, etc., will be
submitted to special tests conforming to the use to which they are to
be put.

IV. TESTS OF COPPER, BRONZE, A^D OTHER METALS.

1. COPPER.

To determine the quality of copper in plates, sheets, bars, and wire,
the following tests are deemed necessary:

A. Copper in plates, in sheets, and in bars:

(1) Tension test.

(2) Cold bending test.

(3) Hot bending test.

B. Copper wire :

(1) Tension test.

(2) Bending test.

(3) Torsion or twisting test.

CONDITION OF THE MATERIAL.

The tests will be made in the condition in which the material is deliv-
ered, or, if desired, those under A will also be made in its soft condition.
To determine the properties of the material in its natural state, it is
necessary to reduce the test specimen to the soft condition. For this
purpose the test pieces, after having been cut out, but before their final
shaping, will be heated in the furnace at a temperature of 600 to
700 C., but not beyond this, then cooled in the air until they are a dull
red, and finally plunged in water at a temperature of 15 C.

CUTTING OF THE TEST PIECES.

The test pieces must be cut out cold by means of a saw, file, or
machine tool, special care being taken that no subsequent straighten-
ing is required. When it does become necessary, straightening must
be done cautiously and, as far as possible, by means of copper hammers
or wooden mallets. If the test is to be made in the soft condition of
the material, then the test pieces, as cut out roughly, may be heated
for the purpose of straightening. In this case, however, they must be
heated once more in order to reduce them to the soft condition.

FORM AND FINISH OF THE TEST PIECES.

The test length I of test bars will be determined, as in the case of
wrought iron and steel (see II, M 1), according to the formula

1 = 11.3 VJ,
wherein / is the cross- sectional area of the bar.

Iii the case of copper, the finishing of the test pieces has an exceed-
ingly great influence on the results of tests; therefore, the utmost
caution should be exercised in shaping test pieces into their final form,
special care being taken never to withdraw the cutting tool within the
limit of the test length, and also to cut only thin shavings toward the
end. The test pieces will be dressed in the direction of their length
and polished with emery. The sharp edges of the test pieces used for
transverse tests will be rounded with a file.

It is recommended also to give a round of 1 mm. radius to the edges
of the flat bars used for tension tests.

EXECUTION OF TESTS.

Tension tests, and the measuring of elongation, will be done as in
the case of iron and steel.

The cold bending test should be made over a mandrel with a diameter
equal to the thickness of the plate, of the sheet, of the bar, or of the
wire. It must not be made at a temperature below 10 0. In the case
of plates, sheets, and bars, those specimens that stood bending around
a mandrel up to 180 are then pressed together until the inner faces
come into close contact. The bending tests of wire will conform to
those prescribed for steel and iron wire.

The hot bending test will be made on bars brought to a cherry red
in a furnace. Those pieces will be bent until rents are produced or
until the interior faces touch. Torsion tests of wire will conform to
those prescribed for iron and steel wire.

2. METALS AND ALLOYS.

To determine the quality of the metals and alloys employed in the
construction of machines and railroads, in architecture, and shipbuild-
ing, the following tests should be made:

1. Tension tests.

2. Compression tests.

3. Transverse tests.

4. Hot and cold bending tests.

The tests will conform to those prescribed for cast iron or those pre-
scribed for copper according to the properties of the material to be
tested. In the first case, tests 1 to 3 are recommended; in the second
case, tests 2 to 4.

The permanent committee was directed to investigate the upsetting test
and to suggest rules for it, not only in the case of copper , brass, and other
metals, but also in the case of iron and steel.

V. TESTS OF WOOD.

1. In order to judge technically of the qualities of wood, as much as
possible of the following information should be procured : Statement of
the place of growth, whether the tree stood isolated or in a crowded

forest, and from what part of the tree the test piece was taken. Finally,
a statement of the age and the time of cutting.

2. On account of the great difference existing between individuals
and between the different parts of the same tree, three samples at least
are necessary to render an opinion.

;>. The outward appearance of each sample should be described as
follows:

A. For the longitudinal section, or, better still, for surface of natural
split, state

(<() Whether the fibers run straight or not.

(b) Whether there are knots ; if so, their nature.

B. For the transverse section

(-) The mean width of the annual layers in millimeters.
(ft) The increase or decrease of width of annual rings in a radial
direction.
(;/) The form of annual rings, whether circular or eccentric.

(d) For trees with needle shaped leaves the approximate relation
between the part of the tree coming from the spring growth and the
part coming from the autumn growth, as apparent from the average of
annual layers.

4. There will be given for each specimen the specific weight not only
in the accidental condition of moisture existing during the test, but
also when air-dried that is, after having been dried at a temperature
of 101 to 105 0. There will likewise be determined the percentage
of moisture of each sample at the time of test, as compared with the
state of air- dry ness. (See above.)

5. The pressure test and the transverse test serve as a criterion of
the strength and the quality of the wood.

(a) The test of compression should be made on prisms 15 cm. long
and with a cross-section 10 cm. square, the test pieces to be mounted
centrally, the two end surfaces exposed to pressure being parallel.

(b) The transverse test will be made on prismatic bars 100 cm. long,
with a square section of 10 cm. by 10 cm. and a clear length of 150 cm.
between the points of support. In order not to injure the test piece
while making the test, there will be placed on it, at the point at which
the load is applied, a rider 2 cm. thick and 20 cm. long, and it will be
protected by still other means if deemed necessary. The flexure will
be pushed to rupture. The rupture of a few fibers or splinters will
not be considered as rupture of the piece.

(c) The strain at the moment of rupture should be calculated by
means of the formula used for flexure, the supposition being that it
holds good up to rupture.

(d) The quality is determined by the work corresponding to the flex-
ure of the specimen of the dimensions before given, the work being

rated by a flexure diagram pushed or carried to the maximum value of
the effort of Hexure.

G. In order to obtain a correct mean for an entire trunk, the various
layers of which are different in character, there should be taken for the
pressure test as well as for the transverse test at least two specimens
from the heart and two specimens from the outer part of the tree, the
outer edges of the latter two being situated in the circumference of
the trunk.

7. The report of transverse tests should be completed by sketches
indicating for each test piece the position of the annual layers with
reference to the direction of the force acting on the piece. Sap wood
will be bent in the direction of the radius, from the center toward the
outside.

YI. TESTS OF SHIPBUILDING MATERIAL.

1. Shipbuilding materials of wrought iron, such as plates, angle, bar,
shape, and rivet iron, should be submitted to the following tests:

(a) Tension test.

(b) Cold bending test.

2. Shipbuilding materials of mild steel, such as plates, angle, bar,
shape, and rivet iron, 'should be submitted to the following tests:

(a) Tension test.

(6) Cold bending test.

(d) Tempering test and bending after tempering.

(e) It is recommended that those who employ mild steel in practice
should examine it witli regard to its welding properties.

Tension tests should be made on bars of standard dimensions cut
from the material just as it is delivered. The strips for bending tests
will be prepared in precisely the same way as described for testing of
boiler plates (see above under II, G- and H). The tempering test and
bending test after tempering will be made as in the case of boiler
plates, with this exception: The bending of the strips by a slow-
working mechanical contrivance will be done around an inner radius,
the size of which depends on the thickness of the plate.

VII. TESTS OF STONE.
A. STONE IN GENERAL.

Stone will be tested according to uniform principles from the point
of view of its resistance to boring and to quarrying.
1. Methods of testing:
The tests of resistance to boring will be made

(a) Either by means of. a jumper drill, or,

(b) l>y means of a rotary boring machine.

If the former is to be employed, it is recommended to take the one
used by the Saxon mining engineer Hausse, in Zankerrode, for testing
the resistance of stone to boring. It is described in the ki Deutsche

Berg- und Hiittenmaimische Zeituug," 1882, Nos. 33 and 34. With this
machine or some similar one, or by means of a rotary boring machine,
the work required for the drilling of a hole of given dimensions is
determined in meter-kilograms.

2. Determination of the most favorable conditions for work before
undertaking resistance tests:

In the case of any given kind of stone, the minimum amount of work
required for a drill hole of given diameter is largely influenced by

(d) The moment of drop of the drill, or, in the case of the rotary bor-
ing machine, the amount of vertical pressure acting on the boring
tool, and its rotating velocity; again,

(b) The shape and cutting angle of the drill or of the teeth of the
borer, and

Preliminary tests are therefore recommended for determining the
most suitable combinations. As a basis of those preliminary tests it
may be assumed that for a hole 25 mm. in diameter bored by impact
the most favorable moment of drop is comprised between G and 9
meter-kilograms, and that for the rotary boring machine the pressure
should probably vary between 30 and 130 atmospheres; also, that in
boring by impact the cutting angle should vary between 70 and 110
and the drill should be turned from one-thirtieth to one- sixth of the
entire circumference at each blow; finally, that for the rotary boring
machines at present in use the most favorable diameter of bore proba-
bly varies between 40 and 80 mm.

3. Special uniform directions :

After the most suitable methods of test of a given kind of stone have
been determined by means of the above preliminary tests, then the
diameter of drill hqle for drilling by impact shall be fixed at 25 mm.,
corresponding to the mean diameter of the one-man drill hole. In order,
however, to determine whether the amount of work required per unit
of drill-hole space is dependent on the diameter of the hole, there shall
also be employed larger diameters. It is recommended to use as such
35, 45, and G5 mm., corresponding to the mean diameters of the two-
man, three-man, and machine drill holes. After having determined
empirically the most favorable moment of drop for a hole of 25 mm.,
there will be applied the law of proportional resistance to find those
which correspond to the above greater diameters of drill holes.

For rotary borings no uniform diameter can be recommended for the
holes on account of the varieties of the existing boring machines.
However, it should be sought to approach as near as possible the
diameters of 45 and 05 mm., recommended for drilling by impact.

4. Other tests:

For the purposes of information, it is desirable that the rocks sub-
jected to the test of resistance to boring should also be submitted to
tests of compression, elasticity, and shearing.

5. Table of borings:

The following form should be employed uniformly to record the results
of the tests :

STANDARD RECORD BLANK FOR BORING.

1. Description of rock from a geological and mineralogical point

of view.

2. Miner's classification (bard, very hard, extremely hard).

3. Texture (for instance, coarse grained, fine grained, layers par-

allel, perpendicular, or oblique to axis of hole bored).

4. Specific gravity of rock.

5. .Diameter of drill hole when drilling by impact.

C. The diameter of hole and core in the case of a rotary boring
machine.

7. Straight or curved edge drills in drilling by impact.

8. Cutting angle when drilling by impact.

9. Number of blows in one revolution of drill when drilling by

impact.

10. Falling weight when drilling by impact.

11. Mean height of drop when drilling by impact.

12. Number of blows that were inquired to obtain observed depth

of drill hole.

13. Number and form of cutting teeth in the rotary drill.

14. Statement of pressure and of velocity with which the rotary

machines were worked.

15. Depth of drill hole.

10. Calculated or indicated drill work done, in meter-kilograms,
per cubic centimeter of drill-hole space. (In the case of
rotary boring only the annular space will be counted.)

B. BUILDING STONE.

a. NATURAL BUILDING STONE.

1. Besides the petrographic and geologic designation of the stone
there must be named the quarry as well as the bench Avhence the speci-
men comes. There must also be given the date of their quarrying and
consequently of their storage in the depot. In the case of great damp-
ness of the quarry, the quarrying should be done in the dry season.

As it is sometimes difficult for those who make the tests to verify the
exactitude of the statements made by the owners of the samples in
regard to their mineralogical designation, it is recommended that this
test, unless expressly demanded, be left out entirely and a statement
to this effect made in the certificate of test. On the other hand, it is
well to correct striking errors in the designation of rocks by notifying
the interested parties in regard to them.

Likewise there may be omitted in certain cases the verification of the
statements as to the quarry and the bench from which the sample has

been taken, the certificate of test with reference to these points then
being worded about as follows: "Said to be taken from - - quarry
and bench."

2. It is recommended that those who are in charge of the tests should
inform themselves before making them as to the use to which the appli-
cant desires to put the materials (building stone, freestone, flagging,
ballasting, paving), and to base tests on that information and not on
the wording of the order.

3. Stone to be used for freestone for structures or substructures should
be tested for compression in the form of cubes with planed faces. These
cubes should be placed between compression plates without any inter-
posed material. One of those plates should move easily in every
direction.

According to the use to which the material will be put, the resistance
to compression will be tested normally or parallel to the bed, or in both
directions. Tests will be made on at least three samples for each
direction.

The samples should be made as large as the strength of the material
and the maximum power of the testing engine may permit, 10 cm. length
of edges being, however, sufficient for stones of inferior strength.

4. There should be measured during the tests, if possible at regular
intervals of pressure, the corresponding loss of height of the test
pieces, in order to be able to draw the diagram of work. There will be
made also in a similar way tension and transverse tests.

5. Before use, the test pieces should be dried in a temperature of 30
G. until their weight is constant.

G. There will be determined always the specific gravity (weight of
unit of volume), and that after drying at 30 C.

7. The test of frost resistance will be made on specimens of uniform
dimensions, as the absorption of water and the action of frost depend
upon the extent of the surface. In view of the dimensions of cement
test pieces, a cube 7 cm. in length of edge is selected here. Only iu
the case of very hard stone, smaller dimensions may be admitted as an
exception; however, in cases of this kind there is very rarely any doubt
about the resistance of the stone against frost.

8. The frost test comprises :

(a) The determination of compressive strength in a water- saturated
state and its comparison with the same strength when dry.

(b) The determination of the compressive strength of the stone redried
after 25 successive freezings and thawings, and the comparison of that
strength with the compressive strength when dry.

(c) The determination of the loss of weight resulting from 25 freezings,
keeping account of the fragments mechanically separated by the frost
and of the substances soluble in a given quantity of water.

(d) The examination of the frozen stone by means of a magnifying
glass, especially to ascertain whether there are produced fissures or
splinters.

0. For the freezing test there will be employed:

For compression tests in a dry state specimens, 3 of which are per-
pendicular and 3 parallel to the bed, unless indeed those tests have
already been made (see above under No. 3). On account of the law of
proportional resistance, test pieces with a greater length of edge than
7 cm. may be used.

For compression tests in a water- saturated state, but not frozen, 6
specimens, 3 of which will be crushed perpendicular and 3 parallel to
the bed.

For freezing tests, 6 specimens, 3 of which will finally be crushed
parallel and 3 perpendicular to the bed.

10. In the execution of frost tests the following details should be
taken into account:

(a) For absorption of water the cubes will first be immersed to a depth
of 2 cm., and then gradually submerged completely.

(b) There will be used for this immersion distilled Avater at a temper-
ature of from 15o to 20 0.

(d) The duration of exposure to cold will be four hours each time.
The test pieces will be thus exposed when completely saturated with
water.

11. The stone having been subjected to the frost test, no additional
test of its weather- wearing qualities is required; but it is desirable to
carefully observe phenomena of this kind occurring in nature, and to
collect experiences made on material in actual service. There should
be observed especially the influence of

(a) The sun, with respect to splitting and cracking.

(b) The air, with respect to the carbonic acid it contains.

(d) Temperature.

p. ARTIFICIAL BUILDING STONE.

a a. BRICKS.

1. For testing a lot of bricks, the least-burned ones should always
be selected.

2. The bricks will be tested for compression in pieces of approxi-
mately cubical shape, obtained by superposing two half bricks and
binding them together by a thin bed of mortar of pure Portland cement.
The pressure surfaces will be smoothed by a similar layer of the same
mortar. At least G specimens will be tested.

3. The specific gravity of the bricks will also be determined.

4. To verify the uniformity of the material the degree of the porosity

of the bricks will be determined. For this purpose they are first dried
and then immersed in water until saturated. Ten pieces are thus com-
pletely dried on a plate of iron and weighed. They are then placed in
water for 24 hours, the water not reaching above half the thickness of
the bricks j after that they are completely submerged for another 24
hours; then, after the surfaces have been wiped, they are weighed
again. There is thus obtained the mean quantity of water absorbed.
The absorption should always be calculated in volume, but there will
be indicated also the per cent in weight of water absorbed.

5. The test of frost resistance will be made in the following ufanner :
(a) Five of the preceding bricks saturated with water will be tested

in that condition for compressive resistance.

(6) The five others will be placed for 4 hours in a refrigerator, the
temperature of which is at least 15 0. They are then taken out and
thawed in water at 20 0. The parts that spontaneously break off
will remain in the thawing vase until the end of the operation. The
freezing is repeated 25 times. The detached particles are dried and
weighed, and the weight obtained is compared with the original weight
of the brick, which latter will finally be examined under a magnifying
glass to ascertain whether there are any fissures or splinters.

(c) After freezing the bricks a compression test will be made. For
this purpose they will be dried. The result will be compared with that
of the compression test made on dried bricks. (See above under No. 2.)

(d) The experimental freezing of bricks does not permit us to judge
absolutely of their resistance to freezing. The value of those experi-
ments is only relative, because they only permit us to recognize the
bricks most destructible by frost.

6. To test bricks with regard to their containing soluble salts, five of
the least-burned ones of the lot which have not yet been in contact
with water are selected. Only the interior is utilized, for which pur-
pose the bricks are split in three directions and the interior edge
chipped off from each of the eight pieces thus obtained. These edges
are pulverized fine enough to pass through a screen of 900 meshes per
square centimeter ; then the fine dust is removed by means of a sieve
of 4,900 l meshes to the square centimeter, and the remaining materials
are used for the test. Of this there will be taken 25 grams, which will
be mixed with 250 cubic cm. of distilled water. This will be boiled for
an hour, replacing from time to time the evaporated water. Then it
will be filtered and washed. The quantity of soluble salts contained
in the brick will then be determined by evaporating the solution and
glowing the residue. The quantity of soluble salts will be indicated in
per cent of weight of the brick.

The salts thus obtained should be submitted to a quantitative
analysis.

1 These are the same sieves as those employed for cement tests. (See below under
VIII, C 2.)

10389 3

7. The tests as to the contents of carbonate of lime, pyrites, selenite,
and other similar materials, should first be made on the uuburnt clay.
For that purpose there will be furnished two bricks not burned. These
bricks will be soaked in water and the coarse parts removed by passing
through a screen of 400 meshes per square centimeter (about one-third
of a millimeter clear width of meshes). The sand thus obtained will be
'examined as to its mineralogical components by means of a magnifying
glass and by treating it with muriatic acid. If impurities are found in
it, such as carbonate of lime, pyrites, selenite, etc., samples of the burnt
bricks for instance, the remnants of the test for soluble salts will be
tested in Papiii's digester as to the possible injurious influence of such
impurities. They will be placed in Papin's digester in such a manner
as not to come in contact with the water, but only with the steam ; the
pressure of that steam should be one-quarter of an atmosphere and the
test should last three hours. There will then be determined, by exami-
nation with a magnifying glass, whether any splintering has taken
place.

ft ROOFING TILES.

1. When roofing tiles are to be tested, the information concerning
them should comprise maximum and minimum dimensions.

2. To determine its specific weight, the material will be pulverized,
that portion of the powder being used which has passed through a sieve
of 900 meshes per square centimeter and has been retained by a sieve
of 4,900 meshes to the square centimeter. This determination will be
made by means of a volumenometer.

3. The weight per unit of volume of the solid fragment will be deter-
mined by the hydrostatic method that is, by measuring the volume of
water displaced by the saturated fragment. Where considerable loss
is apt to be caused through lixiviation, the weight will be determined
by means of the volumenometer, the test pieces being coated with
paraffin.

4. Examination of the capacity for absorption,

5. Determination of the salts soluble in water, and

G. Examination in regard to injurious admixtures, such as slakable
lime, etc., will be made in a similar way to the case of tiles and bricks.
(See above under a a, Nos. 4, 6, and 7.)

7. Examination of the capacity for absorption of the surface of the
tile and of its permeability will be made as follows :

Fragments will be selected of such dimensions that they can absorb
from 20 to 25 cubic cm. of water. Those fragments will be dried, and
their edges will be coated with wax. Finally, there will be affixed on
one of their surfaces, by means of wax, cylindrical tubes of 10 square
cm. cross section.

The following observations are then made:

(a) The 'time necessary for the absorption of 10 cubic cm. of water
introduced into each tube by means of a little pipe.

(&) The time necessary to produce sweat on the lower surface of the
fragment after a new introduction of 10 to 15 cubic cin. of water.

(c) The time necessary for the formation of drops on the lower face
after a new introduction of 10 cubic cm. of water, and the quantity of
water collected in case of permeability in a vessel placed under the
fragment.

8. To determine the transverse strength of roofing tiles, two bands of
Portland cement, 1 cm. in width and 20 cm. apart, will be run across
the lower face. A similar band will be run across the upper surface
of the tile, mid way between the two lower ones. The latter will serve
as supports of the tile during the test, while the upper band will receive
the load.

C. PAVING AND BALLAST MATERIAL, NATURAL AND ARTIFICIAL.

1. Information regarding the petrographic and geologic nature of the
material, its origin, etc.

2. Information concerning the use to which it is to be put, the same
as for natural building stone. (See above under B, a.)

3. Determination of the specific weight of the samples.

4. All road-making materials that will be exposed to frost when in
actual use should be subjected to frost tests, according to the rules
given for natural building stone. (See above under B, a, Nos. 7 to 10.)

5. The best test for sidewalk stones consists in determining their
resistance to wear. For this test it is recommended to employ the
process published by Professor Bauschinger in No. XI of his* Mit-
theilungen.

For burnt stone the regularity of wear from the outer skin toward
the interior should be determined by repeated tests on the same sam-
ple. Those tests must not be confined to a single sample of the material
to be tested ; in fact it is necessary to select for testing from the
entire lot samples of the least, of medium, and of the best quality it
contains.

6. The value of paving materials, enrockment or macadam, can be
determined conclusively only by the construction of trial roads, sub-
jected to a traffic, in kind and weight as uniform as possible, per meter
of width. It is highly desirable that as many as possible of such trial
roads should be constructed, all according to a uniform plan. In refer-
ence to this question, special attention is invited to the publication by
Professor Dietrich on "Materials of construction for stone roads."

7. In order to determine the quality of new paving materials more
rapidly than is possible by their introduction into trial roads, and also
in order to obviate the necessity of constructing a separate trial road
for each new material, a more rapid process for testing stone is
required. Materials for pavement and broken-stone roads being sub-
jected at once to wear and to breakage, it is recommended to test them
in revolving drums such as have been used for a long time in France,

and are described in the above-mentioned publication of Professor
Dietrich; but with a view of augmenting the intensity of the shock, the
dimensions of those drums should be increased, giving them a diameter
of 30 cm. and a height of 50 cm. The velocity of rotation should also
be increased.

It should be remarked here that the preparation of the broken -stone
samples must not be left to the applicant, but for the sake of uniformity
should be done by those making the tests.

On account of the perpetually changing conditions of the drill the
above test is preferable to the drilling test, and pains should be taken
in practice to compare its results with the results obtained by the con-
struction of trial roads.

8. Besides this drum test, compression tests should also be made,
notably on enrockment materials, which are always exposed to crushing.
This test will be made on cubical specimens having a uniform length of
side of from 5 to 7 cm.

9. Paving stones should be tested with regard to the tendency to
wear smooth.

10. For paving and enrockment materials it likewise appears neces-
sary to select samples for test from the worst, the mean, and the best
of the lot, as for those materials homogeneousness of grain is almost
the principal factor.

11. Tests of asphalt can be made exhaustively only by the construc-
tion of trial roads. To be able to give a suitable opinion of the results
of that test it is necessary

(a) To determine the quantity and the quality of bitumen contained
in the asphaltum, whether natural or artificial.

(6) To determine physically and chemically the residue.

(c) To make tests of specimens of the same specific density as the
street material employed, by means of Yicat's standard needle of 1
square cm. circular cross section.

(d) To determine the wear of such pieces by abrasion.

(e) To determine the resistance to frost of those specimens.

D. TESTS OF PRESERVATIVES FOR NATURAL AND ARTIFICIAL

STONE.

1. The tests of natural and artificial building stone from the point of
view of their preservation should be made by tension.

All results obtained up to the present from the testing of preservatives agree in
demonstrating that they always tend to produce an increase of strength, or, at any
rate, a diminution of the loss of strength caused by saturation and repeated freezing.
As all materials used for preservation form surface coatings and do not fully per-
meate the stone, it appears proper to employ for the tensile tests test pieces of small
cross-sectional area. Great size of surface as compared with volume will make the
action of preservatives more pronounced and is, therefore, an additional reason for
the above form of test pieces.

2. The normal German standard of 5 cm. of minimum cross section
will be adopted for the test pieces.

All natural building stones which are in need of preservatives being soft, there is
no difficulty in giving them the standard form. For shaping artificial stone the
German pattern can be used.

The German testing machine is directly adapted for the tension testa.

3. Three specimens are sufficient for each series of tests. Where
important anomalies are found five additional specimens will be tested.

4. The method of testing- the resistance to frost prescribed for nat-
ural and artificial stone under No. VII, B a and No. VII, B ft will also
be applied to the testing of preservatives. Besides that, tests are
recommended for the purpose of determining the durability of the pre-
servative effect. In practice it may be sufficient to repeat the above
tests after one, three, and five years.

5. There may exist preservatives the action of which consists not so
much in increasing the strength of the stone as in protecting it against
atmospheric destructive agents through obstruction of the surface pores.
In these cases the apparent porosity should be determined by measur-
ing the capacity of absorption of uniform test pieces, in percentages of
their weight, before and after having been treated with the preservative.

6. The application of the preservative material to the test pieces
should conform to the method in which that product is used in prac-
tice. It is recommended that the treatment should vary according to
the nature of the preservative, as the method of its use may also exer-
cise a considerable influence on its action.

VIII. TESTS OF HYDRAULIC BINDING MEDIA.

A. GENERAL REMARKS.

1. When it is a question of binding media intended for a given pur-
pose, the test should be made with respect to such purpose as well as
with respect to the available materials used in mixing (such as sand,
gravel, slag, etc.). Those tests must not be replaced by those known
under the name of "standard tests."

Sewer pipes and covers should be tested according to the methods
of Professor Bauschinger. (See Mittheilungen aus dein mech. tech.
Laboratorium der tech. Hochschule in Miinchen, Heft VII.)

2. The tensile and compressive strength as derived at present from
standard tests does not by itself furnish conclusive evidence in regard
to the durability of structures. This is influenced to a very great
extent by other important factors, such as resistance to weather,
impermeability to water, adhesive strength, and constancy of volume.
It being impossible to fully utilize the strength so far already obtained
for cement mortars, it does not appear necessary to seek to increase it.

B. NOMENCLATURE.

1. Hydraulic limes are products obtained by the calcination of lime-
stones containing more or less clay or silicic acid, and which, sprinkled
with water, are slaked entirely or partially into powder. According
to local cireumstances, the lime is delivered in commerce in the form of
lumps, or, hydrated, in the form of powder.

2. Roman cements are products obtained by the calcination, below
the verge of vitrification, of marl containing much clay. They do not
slake when sprinkled with water, and it is necessary to employ mechan-
ical means to reduce them to powder.

3. Portland cements are products obtained from the calcination, up to
the verge of vitrification, of natural marl, or of artificial mixtures of
substances containing clay and lime. They are reduced to powder by
grinding, and contain at least 1.7 parts, by weight, of lime for 1 part of
the material which gives to tbe lime its hydraulic property. To regu-
late certain properties of technical importance, there may be added
foreign material up to 2 per cent of the weight without this addition
necessitating any change of name.

4. Hydraulic admixtures are natural or artificial materials which
generally do not harden under water when alone, but only when mixed
with caustic limes. Such are Pozzuolana, Santorin earth, trass obtained
from certain volcanic tufa, furnace slag, burnt clay, etc.

5. Pozzuolana cements are products obtained by intimately mixing
powdered hydrates of lime with hydraulic mixtures, ground to the fine-
ness of dust.

6. Mixed cements are products obtained by intimately mixing manu-
factured cements with suitable admixtures. Such binding media should
be formally designated as mixed cements, with an indication of the
materials entering into their composition.

O. TESTS.

1. Weight.

(a] The determination of the specific weight of hydraulic binding
media that is to say, of their grains will be made uniformly by means
of the so-called volumenometer.

(b) For the determination of volume weight (or apparent density) of
a hydraulic binding medium there will be used a standard cylindrical
vase of the capacity of one liter and 10 cm. in height, into which the
material will be passed, as follows :

(a) Passed in mechanically through a sieve by means of a Tetmajer
apparatus.

(/?) Shaken in mechanically by means of a Tetmajer apparatus.

(y) Poured in by hand, making use of a funnel apparatus for filling,
and of the standard liter vase.

2. Fineness of grain. The fineness of grinding in hydraulic binding
media will be determined by means of screens from 900 to 4,900 meshes
per square centimeter for Portland cement, and from 900 to 2,500

meshes per square centimeter for the other hydraulic binding media,
the quantity to be employed for each test being 100 grams. The wire
of the screens should have the following dimensions:

For screens of 4,900 meshes, 2,500 meshes, and 900 meshes per square
centimeter, the diameter of wire will be respectively 0.05, 0.07, and
0.1 mm. It is recommended always to employ screens from the same
makers.

3. Conditions of setting.

a. FOR ALL HYDRAULIC BINDING MEDIA EXCEPT POZZUOLANA (TRASS).

(a) The study of the conditions of setting should always be made at
a temperature of from 15 to 18 0.

(b) The investigations should be made on a paste of normal consist-
ency. To determine that consistency there will be used the standard
needle combined with the consistency measure, which is composed of a
rod 1 cm. in diameter, with a weight of 300 grams, and a cylindrical
box 8 cm. in diameter and 4 cm. high, made out of a substance imper-
meable to water and a nonconductor of heat (preferably hard rubber).

To determine the normal consistency there should be mixed 400 grams
of the hydraulic binding medium with a certain quantity of water, so as
to form a thick paste, which will be worked by means of a spatula in
the form of a spoon for exactly 3 minutes for the slow-setting cements
and for 1 minute for the rapid-setting cements. This paste is then
placed into the box without shaking, and after smoothing the surface
the rod is cautiously rested on it and allowed to sink into the paste.
The consistency of the paste will be considered a standard one if the
progress of the rod is arrested at a height of 6 mm. above the bottom of
the box.

(c) The conditions of set will be determined by a standard needle
weighing 300 grams and having a circular section of 1 square mm., and
with the same box as above.

Four hundred grams of the binding medium to be tested are mixed
to a paste with the quantity of water previously determined, as shown
under &, the duration of working the paste being (as under b) 3 minutes
for slow-setting and 1 minute for quick-setting binding media; then the
paste is filled into the box as above.

Hardening has commenced when the needle can no longer completely
penetrate the material. For rapid-setting material the commencement
of hardening can also be determined by means of the thermometer.

To determine the duration of set the box will be turned over. All
hydraulic binding media may be considered as having set when the
standard needle no longer leaves any imprint on the cake of mortar.
The time necessary to obtain that result is termed the " duration of
set."

The designation of hydraulic binding media as quick or slow setting
is governed by the commencement of hardening.

(d) The following test maybe made preliminary to the determination

of the duration of set. There are mixed 100 grams of the cement to
be tested with the water necessary to form a paste of normal con-
sistency, which is worked for 3 minutes or 1 minute, according to
\vhether the material is slow setting or quick setting, and then spread
on a glass plate in a cake about 2 cm. thick. This cake may be con-
sidered as set as soon as it resists a slight pressure of the finger nail.

(e) Besides testing the conditions of set with pastes of standard
consistency, it is desirable that they should also be tested with paste
prepared with greater quantities of water.

/?. FOR POZZUOLANA (TRASS).

Pozzuolana reduced to fine powder and dried at a temperature
between 100 and 110 C. is tested from the point of view of the loss of
water of crystallization by calcination, and from the point of view of
the commencement of hardening under' water, by means of a normal
needle of 300 grams with a circular section of 1 square millimeter.
(See above under a c.) This last test is made as far as possible at the
temperature of 15 C.; at any rate a record of the temperature will be
kept, the mixture used for the test being 2 parts by weight of Pozzuo-
lana, 1 part by weight of hydrate of lime in powder, and 1 part by
weight of water. This mortar, filled into the box and smoothed off,
will be immediately submerged in water and tested after two, three,
four, and five days to determine the weight under which the above
standard needle will completely penetrate it, the box used not being
higher than 4 cm.

4. Constancy of volume.

(tv) Portland cement.

(a) To determine rapidly the constancy of volume of Portland cement
when hardening in water or under conditions preventing it from
becoming dry the following test is recommended:

The cement is mixed with water to a paste of standard consistency
and then spread on a plane thin glass plate so as to form cakes of from
8 to 10 cm. in diameter and about 2 cm. thick. Two of those cakes,
which must be protected against desiccation to avoid cracking, are
placed after 24 hours, but under no circumstances before they have
set, on a metallic plate, plane side down, and submitted to a tempera-
ture from 110 to 120 0. until evaporation ceases (but at least for 1
hour).

If after that operation the cakes show neither warping nor cracks
on the edges, the cement may be considered as possessing constancy
of volume ; otherwise recourse must be had to the cake test on glass
plates, which is at present universally employed and considered
decisive.

The presence of more than 3 per cent of anhydrous sulphate of lime
(or the corresponding portion of unburnt gypsum) will prevent the
above-described test from being conclusive.

(b) The decisive test for constancy of volume is that of the cakes
on glass plates. It is made in the following manner:

One hundred grams of the cement to be tested are mixed with water
to a paste of standard consistency and then spread on a plane glass
plate into a cake 2 cm. thick. Two cakes thus obtained, and protected
against desiccation to avoid cracking, are placed in water after 24 hours,
but certainly not before having set. The cement tested may be con-
sidered as possessing constancy of volume if at the end of 28 days the
cakes do not show any warping or cracks on their edges.

(c) The boiling test may undoubtedly be considered as the most con-
clusive and rapid test for the determination of constancy of volume of
Portland cement, of slag cement, and of trass.

The boiling test, as described below, has been referred to the subcom
mitteefor examination and report.

Fifty grams of the cement to be tested are mixed to approximately
standard consistency that is, with 13 to 15 grams of water and after
having been worked for 1 minute are spread on a glass plate into a cake
1 cm. thick in the middle and thinning out toward the edges. This cake is
kept for 24 hours in a covered receptacle, saturated with steam, then placed,
either after having been detached from the glass plate or together with it,
into a bath of cold water, which is slowly brought to the boiling point that
is, say, in about 10 minutes the lid being kept on in order to reduce evapo-
ration. The cakes should be entirely submergedin the boiling water; ichen
any water has to be added, this should be done in small quantities, so that
the boiling point is quickly restored.

It is, moreover, recommended to the permanent committee to consider
also the mixtures of cement and sand in their investigations of methods for
determining constancy of volume.

From the experiments of Professor Bauschinger it was found that cements which
had given favorable results by the "standard-cake test" (see above under b) not
only after 28 days but also after six months and a year would fail when mixed in
thti proportion of 1 to 3 and formed into prisms of 5 square cm. cross section and 12
cm. length ; expansion was perceptible after six months in Bauschinger's apparatus
and after a longer period also with the naked eye.

(#) Hydraulic limes and Koman cements:

(a) For those materials the cake test under water, described before
under a, b is recommended.

(b) The study of the boiling test (see under a, c) has been assigned to the
permanent committee.

(y) Pozzuolana (trass).

(a) For these the following method is recommended: A mixture of 2
parts by weight of Pozzuolana (trass), 1 part by weight of hydrate of
lime in powder, and 1 part by weight of water is placed into a strong
metallic box (say of galvanized iron) open at the top, slightly conical
in shape, from 3 to 4 cm. in height and from 6 to. 8 cm. in diameter on
top; after the mixture has been leveled off, the box containing it is
immediately placed into a receptacle full of water, so that the upper
edge of the box is submerged to a depth of 2 cm. The hardening

mortar should neither rise above the edges of the box nor should it
swell in the middle, arch-like. The bottom of the box should be solid,
in order that the mortar may expand upward only.

(b) The boiling test may undoubtedly be considered the most reliable
and the most rapid test for determining constancy of volume, even
when the material is trass (see above under a c).

5. Tests of strength.

(a) For all hydraulic binding media with the exception of Pozzuo-
lana:

(a) The tests of strength will be made on a mixture of 1 part by
weight of the binding medium with 3 parts of sand. It is desirable,
however, that tests should also be made with greater admixtures of
sand.

(b) The sand employed should be standard sand obtained from quartz
sand> as nearly pure as possible.

The official standard that is to say, the sand to which all compari-
sons are referred is Freienwalde sand which passes through a sieve of
60 meshes and is held by one of 120 meshes per square centimeter.

For other countries outside of Prussia it is optional to procure their
own standard sand, selecting it, however, if possible, so that its influ-
ence on the strength of mortar is the same as that of the standard
Freienwalde sand. Where that is impossible, judicious coefficients of
comparison should be determined.

(c) The wire diameters of the above sieves should be as follows:
Screen of 60 meshes, 0.38 mm. in diameter; screens of 120 meshes,
0.32 mm. in diameter.

(d) The volumetric weigh t^of the standard sand will be determined
by means of the standard liter into which the sand is passed from the
sieves.

(e) The decisive test of strength is the compression test. It is made
on cubes 5 square cm. in section.

(/) The ordinary test of quality (the test controlling the delivery of
materials) is the tension test made by means of the standard German
apparatus on test specimens of German standard form with a cross
section of 5 square cm.

(g) The determination of standard consistency of mortar and the search
for a suitable mechanical method of malting test pieces^ especially with a
view of obtaining equal density of the test pieces for tension and compres-
sion^ remains referred to the permanent committee.

For the present, test pieces for tension and compression may be made
by hand, but as far as possible of the same degree of density.

(h) To determine resistance to tension and compression, six test
pieces of equal age are required for each series. The arithmetical
mean of the four highest values obtained will be considered as conclu-
sive.

(i) All test pieces must be kept for the first 24 hours in a receptacle
saturated with steam j after that, and up to the time of testing, they

will be kept submerged in water, the temperature of which ranges
from 15 to 18 0., and which will be renewed every 7 days.

(A*) The 28-day test is considered conclusive for all binding media.

To judge of the quality in a shorter time there may be determined in
the case of Portland cement the strength of a mixture of 1 to 3 after 7
days.

Concerning the determination of quality in a yet shorter time, viz,
in 3 days, the convention of Vienna has decided upon the following:

The tests of neat cement (Portland cement and slag cement) are not
sufficient of themselves to give exact information concerning those
products.

The test pieces obtained by the use of normal sand in a proportion,
of 1 to 3 do not offer , it is true, a basis sufficiently certain for judging
of the exact value of Portland and slag cements, but they allow the
formation of an approximate opinion on the quality of those materials,
and for this reason the introduction of the 3-day test is recommended.

In this connection the convention recommends that there should be
employed for the manufacture of test pieces only such machines as will
allow the making of tension and compression specimens as nearly
simultaneously as possible and with the standard amount of ramming.

The standard sand employed must, of course, be pure quartz sand.

For the determination of compressive strength there should be
employed machines of precision.

The permanent committee remains charged with the elaboration and sub-
mittal of short-time tests of quality for the other hydraulic binding media,
special attention to be paid to chemical analysis. Consideration of the
needle test iy this connection (determination of the weight under ivhich a,
needle or a piston will penetrate to a given depth into the binding medium
when in the process of hardening) as well as of the influence of warm baths
on the acceleration of hardening will also be given.

(ft) The tests of strength of mortar from Pozzuolana (trass) should
be made uniformly on a mixture of 2 parts by weight of the Pozzuolana,
1 part of hydrate of lime in powder, 3 parts of standard sand, and 1 part
of water. The manipulation should be the same as for cement, notably
as far as the preservation for 24 hours in air in a room saturated with
humidity before immersion under water is concerned. For certain
special uses the samples may be immersed immediately after their
preparation. In such cases the quantity of water entering into the
composition of the mortar should be increased by one tenth. Observa-
tion of the temperature conditions is of the greatest importance for all
Pozzuolana mortars ; if at all possible there should be employed water at
a temperature of from 15 to 18 C. for the preparation and immersion
of the test pieces. There should be employed for the test of Pozzuolana
mortars only the pure lime coming from marble, since the strength of
the mortar depends a great deal upon the lime.

Where the managers of works of construction produce their Pozzuo-
lana (trass) themselves from tufa, the rock from which the samples for

testing are to be taken will be powdered sufficiently fine to allow 75 per
cent of it to pass through a sieve of 900 meshes, and 50 per cent to pass
through a sieve of 4,900 meshes to the square centimeter, the thickness
of wire being as given above.

During the process of powdering coarse particles must not be thrown
out, but the process must be continued until the entire quantity has
been reduced to the requisite degree of fineness.

6. Adhesive strength. The devising of satisfactory methods of test, in
which will be employed as far as possible the normal German apparatus
for tests of tensile strength, remains referred to the permanent committee.

7. Density. This may be determined either by means of the well-
known mortar volumenometer or by a calculation according to StahPs
method. (See for a description of that method No. 14 of Mittheilungen
aus dem mech. tech. Lab., etc., pp. 252-270.)

8. Action of sea water on hydraulic binding media. In consequence
of a paper read by Professor Debray at the Berlin convention the per-
manent committee was instructed :

To study the action of sea water on hydraulic binding media.

When the report on this subject was submitted to the Vienna con-
vention opinions were found to differ, even in regard to the form of the
test pieces and the methods of test. The question was, therefore, once
more referred to the subcommittee, which was instructed to adopt its
own methods of test and to take into consideration also very poor mixtures
with fine sand.

Besides the old questions indicated herein by italic characters as
having been sent back to the fourth permanent committee by the con-
vention of Vienna, the following questions were also submitted to it:

Determination of the methods of testing materials of construction, nota-
bly iron, with respect to its behavior when exposed to exceptionally low
temperatures.

Determination of the influence of fecal matter on hydraulic binding
media.

Study of abnormal behavior of cements, notably concerning time of set.

Whereas the unification of methods of testing is of great technical and
commercial importance, not only for materials of construction in the Strictest
sense of the word, but also for other raw materials and manufactured prod-
ucts; and

Whereas it is hardly practicable to strictly define the limit of the expres-
sion "materials of construction;" and

Whereas several of the institutes and experts who have taken part at the
convention possess great experience, not only in testing materials of con-
struction, but also concerning technical researches on textile fabrics, paper,
tc., now,

Be it resolved, that the permanent committee is instructed to consider
whether and in what manner the future conventions can arrive at an agree-
ment on uniform methods of testing substances and products of technical
importance.

* ctmpniet

Binder
Gaylord Bros.. Inc.

Stockton, Calif.
T. M. Reg. U.S. Pat. Off.

TA4o<=>

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