El Paso herald. (El Paso, Tex.) 1901-1931, 1913-10-12
And You Take No
Chances
Disintegration of Cement By AlkaIi
By R Mitchell Faculty, College N M

n I'VE OR SIX years ago there was
much discussion concerning the
effect Of sea water and other al
kali waters, particularly of the south
west, upon concrete and other hydrau-
lie constructions used for foundations.
Much work was at that time started
by different Investigators ali over the
world and some Of the results obtained
are just now coming to the knowledge
of the public. Richard K Meade, Of
Baltimore, Nd, recently read a paper
before the American Society for Test
ing Materials, at Atlantic City, outlin-
ing the results Of several years exper-
iment work on the effect of the treat
ment of concrete briquettes with various
alkalies. Edmunde Burke and Reuben
NJ Pinckney, chemists at the Montana
experiment station, have published re-
suits Of experiments, which have been
show the action of alkalies on different
kinds Of ground cements.
Changes in Three Months.
Results to date show that the cement
gradually gets stronger during the first
three months exposure to the action
OF most alkanes in solution, but be-
gins to get weaker after this period,
and some kinds of cement treated with
certain kinds OF a1kalies disintegrate
entirely after a period of one year
Binding Material Attacked.
The work done at the Montana ex-
pertinent station demonstrated that the
disintegra ton of the cement is due to
the destruction of the crystaIized lime,
which is conceded to be the binding
material formed when cement sets. This
binding material reacts chemically with
the alkali salts in the water and forms
other solid materials in the space for
merIy occupied by the crystalized lime,
which expand and act like a wedge,
thus gradually cracking the whole mass
and finally breaking 1t down COM
pletely.
Kind of AIkaIi Most Effective.
Most Of the common aIkalies, both
white and black, were used in these
experiments. and different strength So
buttons were tried out with the result
that some damage was shown with
every kind used. The sulphate alkalies
were shown to be the most detrimental
These include the sulphates of magne-
SUM (epsom salt), of sodium (glauber
salt), and of calcium (gypsum). Chic
ride Of magnesium (bittern) is shown
to be almost as detrimental as the sui
phate, while the chloride of sodium
common table salt) shows very little
i'll effect on the cement briqUette,
Mine Props INVESTIGATED.
Concrete props are often used in
with dilute solutions Of sulphuric acid
To investigate the chance of disinte~
grafton in such cases, briquettes repre-
senting concrete for such purposes were
were disintegrated in one year
Sea Water Most Detrimental.
Sea water is composed of about three
percent of a mixture of the various
alkalies above mentioned, which fact
alone places il at the head of the list
of objectionable waters for the pres
ervation of, concrete. However, the
constant motion of such water makes
it doubly Objectionable.
Experiments on Small Scale.
The experiments 10 date on cement
or concrete have been mostly on the
ground cement and small briquettes,
composed Of material of the same con-
sistency as the concrete used for build
ing piers, etc. Fortunately, the results
thus far obtained would not tend to
revOlutionize the hydraulic cement in
dustry, nor would they retard the use
Of this most excellent material. but
they do show the necessity for extreme
caution and exactness in the construc-
ton of concrete piers. dams. sewers,
and hydraulic foundations
Value of Experiments.
The use Of the small briquettes in