The Birmingham age-herald. [volume] (Birmingham, Ala.) 1902-1950, 1910-01-08
LETTERS TO THE EDITOR
Working With Concrete.
he Editor of The Age-Herald:

To the Editor of The Age-Herald:
Your article on concrete houses in
late issue of your paper is interesting,
because of the many obstacles to be
overcome before houses can be built gem
orally on the plan Mr.. Edison is now
trying to perfect
Having given this subject careful con-
sideration for over two years past and
after investigating tho systems in use.
I find only one that meets the require
ments of architects and engineers.
That of hydraulic pressed stone, which
has been in use for sufficient length
of cheap, durable and strong building
material for general use.
1t is in fact a concrete stone, differing
from the common cement blocks as now
made, both in appearance and density.
owing to the manner OF its manufacture;
under hydraulic pressure of 200 tons.
and its being condensed one-third in
volume.
AS Portland cement has no binding
power except through capitalization 1t
binds nothing when either dry or wet
until 1t appropriates the elements con-
tanned in the water. 1t then forms a
new substance which pushes out against
and into the surrounding aggregates,
catching hold of them and binding them
together. Uncrystalized cement has no
more value or virtue In stone than so
much loose sand or other material
THE initial set" begins in about two
~ xuft he
one-half the silicates are formed, the
strength and imperviousness of the stone
depending largely on the formation of
the early crystalizing silicates. The guam
tity of water must be right Too much
of it is as bad as too little. Hence, the
Importance of using a proper quantity
that the stone will not craze and hair
crack-which affects it's durability and
beauty.
The correct amount Of water Is between
the dry or semi-wst mix and pouring
mix: We call It plastic MIX which
complies with the specifications OF arch
itects and engineers generally.
The hydraulic system Is the only one
that has been brought to the knowledge
of the writer that complies with same
fully, because the aggregates are brought
into close union by great pressure GOO
tone) and held together until the initial
set takes place as above.
Now we approach the important ques-
ton of density To secure greatest
strength both crushing and breaking and
small absorption of moisture, true
concrete stone must have the same dem
sity at It's center as on It's surface and
all attempts to procure this density have
failed until the system OF hydraulic pres
sure combined with the hammering and
tamping was applied to the manufacture
of hydraulic pressed stone.
No argument IL necessary to prove that
density, strength and durability go to-
gether. 1t Is true of natures products
of stone and the closer we get to nature
the surer are we of success In producing
mechanically and chemically true stone.
BY the system referred to the appli-
cation of hydraulic power (automatical-
ly applied produces a great pounding
tamping pressure that puts this system in
class by itself, It being modern,
correct and perfected system of stone
making. No system of pouring into
molds or other means OF forming concrete
blocks or stone will meet the strict APP
plications necessary to meet all the con-
ditions for its use
We reinforce concrete to add to its
strength The adhesion OF the concrete
to the rods or other steel forms binds
them together and as 1t Is impossible
to get the density and strength some
artificial means must be used to protect
the concrete from fracture. BY tho in
PRODUCTION of the hydraulic system
fnforciug is not necessary, the aggre-
gates being pressed and tamped at the
same time and are condensed % per
cent And condemnation being even and
uniform and perfect, It leaves no voids
or air cells. admitting Of the proper guam
tity of water to be used Ia the mixture
and less water to cure the Store after