The Palatka news and advertiser. [volume] (Palatka, Fla.) 1908-19??, 1915-06-25
OLD-M|XED CONCRETE
Experiments in the Depart
ment of Agriculture De-
monstrate Its Value
in Many Kinds
of Buildings.

y
vice tests the department has secured
results which appear to establish de
initely the value of oil-mixed concrete
for damp-proof construction. Detail
ed results of these tests, which were
carried out in connection with The
work of the Office Of ruhlic Roads
are contained in the new bulletin, No
23c, of the department, entitled Oil
liked Portland Cement Concrete.
Eriefy summarized, the conclusion;
to be drawn from them are that the
IadmiXture of certain mineral oils ir
small proportions, not to exceed 1C
per cent of cement used, does not les
sen the tensile strength of mortar;
that the decrease in the compressive
strength of mortar and concrete is not
serious; that concrete mixed with oil
takes much longer to set hard, per-
haps twice as long, but that the in
crease in strength is nearly as rapid
in the oil-mixed material as in the
plain concrete. The use of oil does
not make the concrete impervious to
heavy water pressure, but it does
make it practically nonabsorbent I'M
der low heads.
The value of oil-miXed concrete is
said to be particularly great in the
construction of basement floors and
walls, watering troughs, cisterns,
barns, silos, and in all parts of con-
crete structures that are to be made
damp proof.
The oil should in no case exceed 10
per cent of the weight of the cement,
and for the most part per cent is
all that is necessary. Since bag of
cement weighs "a pounds, At pounds
of oil, or about 2 1-2 quarts, should
be added for each bag of cement used
in the mixture. The sand and ce-
ment should be first mixed with the
proper amount of water into a stiff
mortar, to which is added the cor
rect amount of oil, and the whole
mass again thoroughly mixed until all
traces of oil have disappeared. Par
ticular care should be taken to in
sure that the oil is thoroughly incor-
porated in the mixture, and the time
of mixing should be practically doub-
lie that when the oil is not used. For
this reason continuous mixer should
not be used in il-cement-concrete
work, as it is difficult with this type
of machine to increase the time of
mixing sufficiently.
The kind of oil is also important,
and the following technical specifca-
tions are suggested in the bulletin in
order to prevent the use of certain oils
which might tend to impair the
strength of the mortar or the con-
crete.
Q The oil shall be fluid petro
leum product and shall contain no ad-
mixture of fatty or vegetable oils.
(2) 1t shall have a specific gravi-
ty not greater than O.945 at tenn
perature of % degrees C.
(3) 1t shall show a flash point of |
not less than $50 degrees C. by the
method
az When 24O &C. of the oil is
heated in an Engler viscosimeter to
so degrees c., and maintained at that
temperature for at least three min
utes, the first 100 &C. which flows out
shall show a specific viscosity of not
less than Is nor more than 80
(5) When l part of the oil is
shaken up with parts of hundredth
normal caustic soda there shall be no
and upon allowing the
mixture to remain quiet the two COM
oonents shall rapidly separate in dis
,inct layers.
For practical use the addition of
Ill will be found particularly useful
n the construction of basement floors
md walls. Many of these now in ex-
stence are continually damp, and
uch condition may be remedied
~ the application of an oil-mixed
MORTAR coat to the old surface. A
MORTAR composed of part of cement {
md 2 parts sand and containing ) ,
,er cent of oil should be sufficiently |
onabsorbent for this purpose.
Watering troughs and cisterns {
made of oil-miXed concrete should al |
o prove Of considerable practical val |
e in the conservation of water. In I
he construction of barns, where oil s
mixed concrete is used. the interior
1ill be noticeably drier than when or t
mary concrete is used. Owing to {
heir durability, cleanliness, and re-
istance to fire, concrete barns are
ecoming more and more popular, {
ut they suffer from the disadvantage
hat during a long beating rain the e.
ide walls are inclined to absorb much
Moisture, which ultimately penetrates
ITO the interior. The addition of oil a
D the extent of per cent of the n
eight of cement in the concrete used T
l the side walls obviates this OBJ r.
ection. Barn floors can also be con- G
tructed in the same way with adj \
antage. A damp-proof floor is s.
'armer because of the lack of evapo- c,
alton from its surface, and it is also il
lore sanitary than an ordinary con-
'ete floor because of its nonabsorb- f
Mt character. Il
There are, of course, any number of T
Their types of buildings and struc-
res of all sorts in which oil-mixed go
,ncrete may be used advantageously. ID
r, if this is not necessary, a coat of
Linked mortar may be applied eff y,
actively. Il
Attention is called, however, to the ?;
ict that extreme care in proportion 10
e, mixing, and placing the concrete r
absolutely necessary if the addition fr
any waterproofing agent is to be u,
value. The process of mixing oil al