The daily telegram. [volume] (Clarksburg, W. Va.) 1901-1926, 1912-08-20
TESTS
With High Pressure Steam
Are Being Made on
Portland Cement.

Portland Cement.
wAsHlraGroM d, C.. Aug. 2o.-
The Bnrean Of Standards. of the Des
partment Of commerce ana Labor. IL.
connectinn with the investigation q
structural materials is conducting s
series of tests 70 determine the action
Of high pressure steam on Portland.
cement. II has been found that high
pressure steam win greatly accelerate
the hardening of certain cements, insi
creasius their strength several huns
dEed per cent. hut VIII cause the eoms
plete dlsintesration Of other cementsI
which under normal conditions aBsI
pear to have the usual physical quail
tiles. The present investigation Is IN
part an extension Of the work report
ed in Technologic Paper No. 5. THE
Effect OF High Pressure stem on the
Crushing Strength of Portland ce-
ment Mortar and and Concrete" The
equipment for this purpose consists
Of small steam=pressure tank, or So
called 'autoclave.': suitable for pres
sures up to 80 atmpspheres t5l5
poands per square ipchl and large
cylindrical steel tank. ~ inches by 81
feet inside dtmenslons suitable for
working pressures, up 70 20 atmos-
pheres u,O3O pounds per square
inch).
II has been proposed that specifi-
cations for the, purchase OF Portland
cement be amended to include test
Of exposing cement to steam pres
sure of 20 atmospheres CHA pounds
per, square inch) for a period OF two
hours. 1t is required that the cement
remain sound and that the tension
briqusttes show given Increase in
strength.
Il has been found that certain ce-
ments which meet the steam test of
212 degrees F. for 5 hours, as required
by present specifications, fail under the
proposed high-pressure. steam test.
In investigating the cause and inter
probation OF this failure, practically
all brands of cement purchased by
the government are being subjected to
the high-pressure steam test in con-
nectlon with the regular routine spec
iication test. and much valuable in
formation Is being accumulated.
Tests are also being made on spec
tally prepared cements OF various de-
grees of oneness and after seasoning
for different periods. Other series Of
tests are being made in exposing ce-
ments neat, and in mortars and con-
cretes to series of pressures ranging
up to 1000 pounds per square inch
for various durauons. Tensile and
compressive strength, linear expan-
sion and contraction. water ABSORB
ton and otheryphysical properties are
being determined. The effect OF tenn
perature, pressure. and moisture con-
tent OF the atmosphere, or degree, OF
water saturation, are being studied in
dependentiy.
Some interesting results are also
being obtained by subjecting to high
pressure steam pieces OF mortar and
concrete from sound and disintegrated
structures. which has been in place
for several years.
To determine the value of the
hlsh-pressure steam test as a deter
mination of the soundness, and. struc-
tural quality of Portland cements, a
large number of concrete sylinders s
inches in diameter by 16 inches in
, length, are being made of cement
which fails to meet the normal 212
degrees F. steam test, as well as Of
cement which passes this test but
falls to meet the proposed 20 atmos-
phere steam pressure test, and of CO.
ment which meets both of the above
requirements. The cements are being
tested in normal 1:2:4 proportion
concrete mixture and Will be exposed
in various localities over period of
years and tested for, elastic proper
ties and compdessive strength.