Edwin Clarence Eckel.

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than two months old.

(3) Tests. — ^The cement shall be subjected to the following tests:
(a) Blowing test, — Mortar pats of neat cement thoroughly worked

shall be troweled upon carefully cleaned 5-inch by 2J-inch ground-
glass plates. The pats shall be about i inch thick in the center and
worked off to the sharp edges at the four sides. They shall be covered
with a damp cloth and allowed to remain in the air until set, after which
they shall be placed in vapor in a tank in which the water is heated
to a temperature of 130° F. After remaining in the vapor six hours,

* Proposed Canadian standard specifications for Portland cement. Cementt
voL 4, pp. 98-99. May, 1903.



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SPECIFICATIONS FOR PORTLAND CEMENT. 623

including the time of setting in air, they shall be immersed in the hot
water and allowed to remain there for eighteen hours. After removal
from the water the samples shall not be curled up, shall not have fine
hair cracks, nor large expansion cracks, nor shall they be distorted.
If separated from the glass, the samples shall break with a sharp, crisp
ring.

(6) Tensile est (neat cement). — Briquettes made of neat cement
mixed with about 20 per cent of water, by weight, after remaining
one day in air, in a moist atmosphere, shall be immersed in water,
and shall be capable of sustaining a tensile stress of 250 lbs. per square
inch after submersion for two days, 400 lbs. per square inch after sub-
mersion for six days, 500 lbs. per square inch after submersion for
twenty-seven days. The tensile test shall be considered as the aver-
age of the strength of five briquettes, and any cement showing a decrease
in tensile strength on or before the twenty-eighth day shall be rejected.
(Sand and cement.) — ^The sand for standard tests shall be clean quartz,
crushed so that the whole shall pass through a sieve of 400 meshes to
the square inch, but shall be retained on a sieve of 900 meshes per square
inch. The sand and cement shall be thoroughly mixed dry, and then
about 10 per cent of their weight of water shall be added, when the
briquettes are to be formed in suitable molds. After remaining in a
damp chamber for twenty-four hours the briquettes shall be immersed
in water, and briquettes made in the proportion of one of cement to
three of sand, by weight, shall bear a tensile stress of 125 lbs. per square
inch after submersion for six days, and 200 lbs. per square inch after
submersion for twenty-eight days. Sand and cement briquettes shall
not show a decrease in tensile strength at the end of twenty-eight days
or subsequently.

(4) The manufacturer shall, if required, supply chemical analyses
of the cement.

(5) Packing. — ^The cement shall be packed either in stout air- and
water-tight casks, carefully lined with strong brown paper, or in strong
air- and water-tight bags.

(6) The manufacturer shall give a certificate with each shipment
of cement, stating (1) the date of manufacture; (2) the tests and
analyses which have been obtained for the cement in question at the
manufacturer's laboratory; (3) that the cement does not contain any
adulteration.



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624 CEMENTS, LIMES, AND PLASTERS.



Concrete-Steel Engineering Company.*

No cement will be allowed to be used except established brands of
high-grade Portland cement which has been in successful use under
similar conditions to the work proposed for at least three years, and
has been seasoned or subjected to aeration for at least thirty days before
leaving the factory. All cement shall be dry and free from lumps,
and immediately upon receipt shall be stored in a dry, w^ell-covered,
and ventilated place thoroughly protected from the weather. If
required the contractor shall furnish a certified statement of the chem-
ical composition of the cement and of the raw material from which it is
manufactured.

The fineness of the cement shall be such that at least 90 per cent
will pass through a sieve of No. 40 wire, Stubbs gauge, having 10,000
openings per square inch, and at least 75 per cent will pass through a
sieve of No. 45 ware, Stubbs gauge, having 40,000 openings per square
inch.

Samples for testing may be taken from every bag or barrel, but
usually for tests of 100 barrels a sample will be taken from everj^^ tenth .
barrel. The samples will be mixed thoroughly together while dry,
and the mixture be taken as the sample for test.

Teasile tests will be made on specimens prepared and maintained
until tested at a temperature not less than 60® F. Each specimen will
have an area of 1 square inch at the breaking section and after being
allowed to harden in moist air for twenty-four hours will be immersed
and maintained under water until tested.

The sand used in preparing test specimens shall be clean, sharp,
crushed quartz retained on a sieve of 30 meshes per lineal inch, and
passing through a sieve of 20 meshes per linpal inch. In test speci-
mens of one cement and three sand, no more than 12 per cent of water
by weight shall be used. Specimens prepared from a mixture of one
part cement and three parts sand, parts by weight, shall after seven
days develop a tensile strength of not less than 170 lbs. per square inch,
and not less than 240 lbs. per square inch after twenty-eight days.
Cement mixed neat from 20 per cent to 25 per cent of water to form
a stiff paste shall, after 30 minutes, be appreciably indented by the end
of a wire inch -f^ in diameter loaded to weigh J lb. Cement made into



* The specifications from which this section is taken were published in Cement,
vol. 4, pp. 105-108, May, 1903. They are for concrete-steel structures on the
Melan, Thacher, and Von Emperger patents.



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SPECIFICATIONS FOR PORTLAND CEMENT. 625

thin pats on glass plates shall not crack, scale, or warp under the fol-
lowing treatment: Three pats will be made and allowed to harden in
moist air at from 60° to 70° F.; one of these will be placed in fresh water
for twenty-eight days, another will be placed in water which wuU be
raised to the boiling-pgint for six hours and then allowed to cool, and
the third is to be kept in the air of the prevailing outdoor temperature.



British Standard Specifications.*

Quality and preparation. — (1) The cement is to be prepared by
intimately mixing together calcareous and argillaceous materials, burn-
ing them at a clinkering temperature and grinding the resulting clinker.
No addition of any material is to be made after burning, except when
desired by the manufacturer, and if not prohibited in writing by the
consumer, in which case calcium sulphate or water may be used. The
cement, if watered, shall contain not more than 2 per cent of water,
whether that water has been added or has been naturally absorbed from
the air. If calciiun sulphate is used, not more than 2 per cent calcu-
lated as anhydrous calcium sulphate of the weight of the cement shall
be added.

Sampling and preparation for testing and analysis. — (2) As soon
as the cement has been bulked at the maker's works, t or on the works
in connection' with which the material is to be used, at the consumer's
option, samples for testing aire to be taken from each parcel, each sample
consisting of cement from at least twelve different positions in the same
heap, so distributed as to insure, as far as is practicable, a fair average
sample of the whole parcel, all to be mixed together and the sample
for testing to be taken therefrom.

(3) Before gauging the tests, the sample so obtained is to be spread
out for a depth of 3 inches for twenty-four hours, in a temperature of
58° to 64° F.

(4) In all cases where consignments are of 100 tons and upwards
samples selected as above from each consignment, either at the maker's
works or after delivery at the works where the cement is to be used,
are to be sent for expert testing and for chemical analysis. In no
case is cement so tested and analyzed to be accepted or used unless

* British standard specifications for Portland cement. Engineering News,
vol. 53, pp. 227-228. March 2, 1905.

t Should the consumer desire to stipulate for any special quantity, the size of the
heap should be stated.



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626 CEMENTS, LIME5, AND PLASTERS.

previously certified in writing by the consumer to be of satisfactory
quality. Payment for such tests and analyses to be made by the con-
sumer, the manufacturer supplying the cement required for the same
free of charge. When consignments of less than 100 tons have to be
supplied, the maker shall, if required, give certificates for each delivery,
to the effect that such cement complies with the' terms of this standard
specification, with regard to quality, tests, and chemical analyses, no
payment being made by the consumer for such certificate nor for the
making of such tests and analyses.

(5) Should it be deemed more convenient by the consumers that
the samples for testing should be taken at the makers' works before
delivery, the latter are, in that event, to afford full facilities to the inspector
who may be appointed by the consumers to sample the cement as he
may desire at the makers' works, and subsequently to identify each
parcel as it may be dispatched, with that sampled by "him. No parcel
is to be sent away unless a written order has been previously received
by the makers from the said consumer to the effect that the material
in question has been approved.

Fineness and sieves. — (6) The cement shall be ground to comply
with the following degrees of fineness, viz.:

The residue on a sieve 76x76 = 5776 meshes per square inch is not
to exceed 5 per cent.

The residue on a sieve 180X180=32,400 meshes per square inch
is not to exceed 22^ per cent.

The sieves are to be prepared from standard wire; the size of the
wire for the 5776 mesh is to be .0044 inch and for the 32,400 mesh
.0018 inch. The wire shall be woven (not twilled), the cloth being
carefully mounted on the frames without distortion.

Specific gravity. — (7) The specific gravity of the cement shall be not
less than 3.15 when sampled and hermetically sealed at the makers'
works, nor less than 3.10 if sampled after delivery to the consumer.

Chemical composition. — (8) The cement is to comply with the follow-
ing conditions as to its chemical composition. There shall be no excess
of lime, that is to say, the proportion of lime shall be not greater than
is necessary to saturate the silica and alumina present. The percent-
age of insoluble residue shall not exceed 1.5 per cent; that of mag«
nesia shall not exceed 3 per cent, and that of sulphuric anhydride shall
not exceed 2.5 per cent.

Tensile tests. — (9) The quantity of water used in gauging shall be
appropriate to the quality of the cement, and shall be so proportioned
that when the cement is gauged it shall form a smooth, easily worked



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SPECIFICATIONS FOR PORTlJVND CEMENT. 627

paste that will leave the trowel cleanly in a compact mass. Fresh
water is to be used for gauging, the temperature thereof, and of the test-
room at the time the said operations are performed, being from 58° to
64° F.

The cement gauged as above is to be filled, without mechanical ram-
ming, into molds; each mold resting upon an iron plate until the cement
has set. When the cement has set sufficiently to enable the mold to be
removed without injury to the briquette, such removal is to be efifected.
The said briquettes shall be kept in a damp atmosphere and placed in
fresh water twenty-four hours after gauging and kept there until broken,
the water in which the test briquettes are submerged being renewed
every seven days and the temperature thereof maintained between 58°
and 64? F.

Neat tests. — (10) Briquettes of neat cement are to be gauged for
breaking at seven and twenty-eight day^, respectively, six briquettes
for each period. The average tensile strength of the six briquettes
shall be taken as the accepted tensile strength for each period. For
breaking, the briquette is to be held in strong metal jaws, the briquettes
being slightly greased where gripped lj>y the jaws. The load must
then be steadily and uniformly applied, starting from zero, increasing
at the rate of 100 lbs. in twelve seconds. The briquettes are to bear
on the average not less than the following tensile stresses before breaking:

7 days from gauging 400 lbs. per square inch of section.

28 days from gauging 500 lbs. per square inch of section.

The increase from seven to twenty-eight days shall not be less
than:

25% when the 7-day test falls between 400 to 450 lbs. per square inch.

20% when the 7-day test falls between 450 to 500 lbs. per square inch.

15% when the 7-day test falls between 500 to 550 lbs. per square inch.

10% when the 7-day test falls between 550 lbs. per square inch or
upwards.

Sand tests. — (11) The cement shall also be tested by means of
briquettes prepared from one part of cement to three parts by weight
of dry standard sand, the said briquettes being of the shape described
for the neat-cement tests; the mode of gauging, filling the molds, and
breaking the briquettes is also to be similar. The proportion of water
used shall be such that the mixture is thoroughly wetted, and there
shall be no superfluous water when the briquettes are formed. The
cement and sand briquettes are to bear the following tensile stresses:

7 days from gauging 120 lbs. per square inch of section.

28 days from gauging 225 lbs. per square inch of section.



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628 CEMENTS, LIMES, AND PLASTERS.

The increase from seven to twenty-eight days shall not be less than

20 per cent.

The standard sand referred to above is to be obtained from Leighton
Buzzard. It must be thoroughly washed, dried, and pass through a
sieve of 20X20 meshes per square inch, and must be retained on a sieve
of 30X30 meshes per square inch, the wires of the sieve being .0164-iiich
and .0108-inch respectively.

Setting-time. — (12) There shall be three distinct gradations of set-
ting-time, which shall be designated as "quick'', "medium", and "slow ".*

Quick, — ^The setting-time shall not be less than ten minutes or more
than thirty minutes.

Medium. — ^The setting-time shall not be less than half an hour or
more than two hours.

Slow. — ^The setting-time shall not be less than two hours or more
than five hours.*

The temperature of the air in the test^room at the time of gauging
and of the water used is to be between 58° and 64° F.

The cement shall be considered as "?et" when a needle having a
flat end -f^ inch square, weighing in all 2i lbs., fails to make an im-
pression when its point is applied gently to the surface.

Soundness. — (13) The cement shall be tested by the Le Chatelier
method, and is in no case to show a greater expansion than 12 milli-
meters after twenty-four hours' aeration and 6 millimeters after 7 dsLVs'
aeration.

Note. — ^The apparatus for conducting the Le Chatelier test consists
of a small split cylinder of spring brass or other suitable metal of 0.5
millimeter (.0197 in.) in thickness, 30 millimeters (1.1875 inches) inter-
nal diameter, and 30 millimeters high, forming the mold, to which on
either side of the split arc attached two indicators 165 millimeters (6.5
inches) long from the center of the cylinder, with pointed ends.

In conducting the test the mold is to be placed upon a small piece
of glass and filled with cement gauged in the usual way, care being taken
to keep the edges of the molds gently together while this operation is
being performed. The mold is then covered with another glass plate,
a small weight is placed on this, and the mold is immediately placed
in water at 58"^ to 64® F. and left there for twenty-four hours.

The distance separating the indicator points is then measured and
the mold placed in cold water, which is brought to the boiling-point in
, . — ■«

* When a specially slow^setting cement is required the minimum time of
setting shall be specified.



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SPECIFICATIONS FOR .PORTLAND CEMENT. 629

15 to 30 minutes and kept boiling for six hours. After cooling, the
distance between the points Ls again measured; the difference between
the two measiu'ements represents the expansion of the cement, which
must not exceed the limits laid down in this specification.

(14) The tests and analyses hereinbefore referred to shall in no case
relate to a larger quantity of cement than 250 tons sampled at one time.

Acceptance. — (15) No cement is to be approved or accepted imlees
it fully complies with the foregoing conditions.



American Society for Testing Materials, 1904.

GENERAL OBSERVATIONS.

1. These remarks have been prepared with a view of pointing out
the pertinent features of the various requirements and the precautions
to be observed in the interpretation of the results of the tests.

2. The committee would suggest that the acceptance or rejection
under these specifications be based on tests made by an experienced
person having the proper means for making the tests.

3. Specific gravity. — Specific gravity is useful in detecting adultera-
tion or underbuming. The result of tests of specific gravity are not
necessarily conclusive as an indication of the quality of the cement, but
when in combination with the results of other tests may afferd valuable
indications. %

4. Fineness. — ^The sieves should be kept thoroughly dry.

5. Time of setting. — Great care should be exercised to maintain
the test pieces under as uniform conditions as possible. A sudden
change or wide range of temperature in the room in which the tests are
made, a very dry or humid atmosphere, and other irregularities vitally
affect the rate of setting.

6. Tensile strength. — Each consumer must fix the minimum re-
quirements for tensile strength to suit his own conditions. They shall,
however, be within the limits stated.

7. Constancy of volume. — ^The tests for constancy of volume are
divided into two classes, the first normal, the second accelerated. The
latter should be regarded as a precautionary test only, and not infallible.
So many conditions enter into the making and interpreting of it that
it should be used with extreme care.

8. In making the pats the greatest care should be exercised to avoid
initial strains due to molding or to too rapid drying out during the first
twenty-four hours. The pats should be preserved under the most



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630 CEMENTS, LIMES, AND PLASTERS.

uniform conditions possible, and rapid changes of temperature shodd
be avoided.

9. The failure to meet the requirements of the accelerated tests
need not be sufficient cause for rejection. The cement may, however,
be held for twenty-eight days and a retest made at the end of that period.
Failure to meet the requirements at this time should be considered
sufficient cause for rejection, although in the present state of our knowl-
edge it cannot be said that such failure necessarily indicates unsound-
ness, nor can the cement be considered entirely satisfactory simply
because it passes the tests.

STANDARD SPECIFICATIONS FOR CEMENT.

1. General conditions. — ^All cement shall be inspected.

2. Cement may be inspected either at the place of manufacture
or on the work.

3. In order to allow ample time for inspecting and testing, the cement
should be stored in a suitable weather-tight building having the floor
properly blocked or raised from the ground.

4. The cement shall be stored in such a manner as to pennit easy
access for proper inspection and identification of each shipment.

5. Every facility shall be provided by the contractor and a period
of at least twelve days allowed for the inspection and necessary tests.

6. Cement shall be delivered in suitable packages with the brand
and name of manufacture!^ plainly marked thereon.

7. A bag of cement shall contain 94 lbs. of cement net. Each barrel
of Portland cement shall contain 4 bags, and each barrel of natural
cement shall contain 3 bags, of the above net weight.

8. Cement failing to meet the seven-day requirements may be held
awaiting the results of the twenty-eight-day tests before rejection.

9. All tests shall be made in accordance with the methods proposed
by the Committee on Uniform Tests of Cement of the American Society
of Civil Engineers, presented to the society Jan. 21, 1903, and amended
Jan. 20, 1904, with all subsequent amendments thereto.

10. The acceptance or rejection shall be based on the following
requirements:

PORTLAND CEMENT.

18. Definition. — ^This term is applied to the finely pulverized product
resulting from the calcination to incipient fusion of an intimate mixture
of properly proportioned argillaceous and calcareous materials, and to



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SPECIFICATlbNS FOR PORTLAND CEMENT. 631

which no addition greater than 3 per cent has been made subsequent
to calcination.

19. Specific gravity. — The specific gravity of the cement, thoroughly
dried at 100° C, shall be not less than 3.10.

20. Fineness. — ^It shall leave by weight a residue of not more than
8 per cent on the No. 100, and not more than 25 per cent on the No^
200-sieve.

21. Time of setting. — ^It shall develop initial set in not less than
thirty minutes, but must develop hard set in not less than one hour^
nor more than ten hours.

22. Tensile strength. — The minimimi requirenaents for tensile strength
for briquettes one inch square in section shall be within the follo^ving
limits, and shall show no retrogression in strength within the periods
specified:

Neat Cement.
Age. Strength.

24 hours in moist air 160—200 lbs.

7 days (1 day in air, 6 days in water) 450 — 550 * *

28 days (1 day in air, 27 days in water) 550 — 650 "

One Part Cement, Three Parts Sand:

7 days (1 day in moist air, 6 days in water) 150 — 200 '*

28 days (1 day in moist air, 27 days in water) 200—300 "

23. Constancy of volume. — Pats of neat cement about three inches
in diameter, one half inch thick at the center, and tapering to a thin
edge, shall be kept in moist air for a period of twenty-four hours.

(a) A pat is then kept in air at normal temperature and observed
at intervals for at least 28 days.

(p) Another pat is kept in water maintained as near 70** F. as prac-
ticable, and observed at intervals for at least 28 days.

(c) A third pat is exposed in any convenient way in an atmosphere
of steam, above boiUng water, in a loosely closed vessel for five hours.

24. These pats, to satisfactorily pass the requirements, shall remain
firm and hard and show no signs of distortion, checking, cracking or
disintegration.

25. Sulphtiric acid and magnesia. — ^The cement shall not contain
more than 1.75 per cent of anhydrous sulphuric acid (SOa), nor more
than 4 jJer cent of magnesia (MgO).



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PART VIL PUZZOLAN CEMENTS.



CHAPTER XLI.
PUZZOLANIC MATERIALS IN GENERAL.

PuzzoLANic materials include all those natural or artificial materials
which are capable of forming hydraulic cements on being simply mixed
with lime, without the use of heat. Many materials possess this property,
but relatively few have ever attained to sufficient conmiercial imjK>r-
tance to be discassed here. In composition the puzzolanie materials
are largely made up of silica and alumina, usually with more or less
iron oxide; some, as the slags used in cement-manufacture, carr\^ aLo
notable percentages of lime. As might be inferred from this eom|XH
sition, most of the puzzolanie materials possess hydraulicity to a greater
or less degree of themselves, but the addition of lime usually greatly
increases their hydraulic power.

The term jmzzolan, here adopted for this group of cementing mate-
rials, is a corruption of the adjective form of the name pozzuolana.
It has no particular etymological excuse for existence, but \{ril\ he
accepted in this volume for the sake of uniformity, as it seems to have
been adopted by various authorities in the United States.

Natural Puzzolanie Materials.

Natural puzzolanie materials are quite -widely distributed, though
they have never attained much conmiercial importance, save in Europe.
As regards their origin, they are of two classes: In the first class may
be included all those which are the direct products of volcanic action,
the material being a fine volcanic ash or dust deposited either on the
slopes of the volcano or carried by the wind to lakes or streams in
which the ash is deposited. This group includes the more active puzzo-
lanie materials, its chief representatives being pozzuolana proper, san-



Online LibraryEdwin Clarence EckelCements, limes, and plasters : their materials, manufacture,and properties → online text (page 54 of 64)