The Prince George's enquirer and southern Maryland advertiser. (Upper Marlborough, Md.) 1882-1925, 1916-05-12
CONCRETE MIXING
ON THE farm
Directions For Preparing Material For
Mixing For Farm Use.
G. P. SPRINGER,
Maryland Agricultural College,

Thers are many ways Of mixing con
crete, but to the person having only a
small amount to handle, up to about
$50 cubic yards, hand mixing is the
only economical method.
Mixing on the basis of a two-bax
batch; meaning batch of concrete
where the basis of measurement is two
bags of cement, 1924 concrete would
require two bags of cement "a bag Of
cement contains one cubic foot), four
cubic feet of sand, eight cubic feet Of
stone or gravel. The tools that will be
required are: A mixing board 9x10
feet, which viii require the following
material:
9pcs. Is in. K II in. I 10 It. % In,
dressed che side and two edges.
pcs. In. Z 4 ink 8 IT. 0 in. rough
pcs. In. x IN K 10 It. 0 In, rough
2pcs in K In 8 #. 0 in, rough
The mixing board should be tight
with the Finch strips nailed around
the edge to prevent water from esnap-
ing.
Runways will require several pieces
Of plank 10x12 inches wide.
A measuring box for sand and stone
WA require for a 1924 mix the follow
Ing material:
3 pcs. In. liz IN. f. o in. rough
pcs. In. Z lIN In 4 1 IT. 0 in, rough
This forms a box two feet square,
the extra length ON two pieces Is for
making handles. There will also be
required two or more square point"
shovels, one or more sheet iron wheel
barrowa, rake, water barrel, sew
oral water buckets, a sprinkilng can,
temper, a spading tool and a sand
screen.
Making The Mi,eturs.
Level the mixing board. place the
measuring box at one side Of the cen
ter, I'LL measuring box level full Of
sand, lift off the box and spread the
sand evenly over the board until four
Dr. six inches deep. Take two bags Of
sement and spread evenly over the
sand. Mix the sand and cement thor
oughly by turning three or more times.
To mix start at the edge of the sand
md cement mass and shovel it over
INTO a new pile. In shovsling do not
lake a shovelful from one pile and
dump it upon the other pile, but in
turning the shovel give it twisting
pril. this will cause the sand and
cement as It falls from the shovel to
scatter and mix. The material is SHOW
sled from one side of the mixing board
to the other at least three times, and
Il properly turned should then show
throughout an even gray color. Spread
out upon the mixing board to a depth
Of four or six inches and place the
measuring box on the center Of the
mass. fill level full of stone, lift off.
and level, replace and fill full of stone
again, lift OF and level down. (Eete
that the box is filed only once with
sand.) Wet the mixing board upon
the side where the mass Is to be
turned, shovel the cement, sand and
stone over to the other side Of the
board sprinkling it as turned. wet
board on other side and turn mass
back again, sprinkling as turned. AS
each shovel of material Is deposited
drag the shovel toward you, this will
spread and mix the wet mass. Turn
and sprinkle where dry spots show I'M
til complete turning will not expose
any dry material. The concrete mass
should now contain sufficient water so.
that tamping will cause water to flush
to the top of the mixture, bringing
with it thin film Of cement to the
surface.
Use At Once.
The concrete is now ready to be
placed in the forms built to receive it,
Concrete should not be allowed to
stand after mixing but should be
placed in the forms at once. If it
stands for time greater than 80 min
utes it will begin to set, and if then
placed in the form will produce weak
structure which will give trouble and
eventually fail.
The materials to be used in the con-
crete, the tools for mixing, the ma
terials for forms, the forms as far as
possible completed, should all be on
the ground where the work is to be
done before any Of the concrete is
mixed. Use only clean water. Mix
quickly and place Immediately in the
forms.
Advice and information concerning
concrete work and other engineering
problems may be had by writing to the
Division of Engineering, Maryland Ag
riculture College, College Park, Md.