The river press. [volume] (Fort Benton, Mont.) 1880-current, 1912-06-05
nder. If too much sand is used the

: nder. If too much sand is used the
): suit will he loose sand on the sur
race; If toe much clay is used the sur
face of Il. road will become sticky
after rains.
The bet mixture of sand and clay
can be made when the materials are
wet. and particularly is this true of
the plastic or ball clays.
II the clay is a plastic or ball clay
much greater effort will be necessary
to obtain a complete mixture; If it is
a shaking clay the mixture will he
much more readily obtained. This
kind Of clay Is not as satisfactory.
however. as the ball clay, as its bind
ing powers are much less. In select
ing clay for road purposes it is always
best to select the stickiest clay avail
able. a common test is to wet the
thumb and place it against a piece of
clay. If the clay will not stick to the
thumb it is safe to assume that 1t will
be a poor binder in a sand-clay road.
AS the desirable proportions of sane
and clay are such that the particles of
clay barely fl. the voids between the
grains Of sand, it Is we'll in determin-
ing the quantity of clay to be applied
to a sand road or sand to be applied to
a clay road to know approximately
how much. is needed. A simple method
for determining the relative quantity
Is to take two glasses of the same size
and fill one with dry sand which it is
proposed to use and the other with va
ter. The water should then be poured
carefully in the glass of sand and al
lowed to trickle down through the sand
until it reaches the bottom of the glass.
When the water has been poured into
flowing we may assume that the voids
between the grains of sand have been
filled, and consequently the amount of
water taken from the full glass would
represent the volume of clay needed to
fill the voids in a volume Of sand equal
to hat in the other glass. 1t is better
to use a little less clay than would ap
pear to be necessary, as the tendency
is to overestin,ate the amount needed.
Good drainage is the most essential
feature of the sand-clay road just as il
is of all other types of road. A sandy
Or gravelly soil affords better natural
drainage, and if the sand is present tc
an exceptional extent the only provi
sion necessary for drainage will be tt
crown the surface of the road in the
SAME ann as prescribed for earth
gravel or maxadam roads. If the roat
is located through land that is so low
as to be continually wet it will be nee
essary in addition to browning the roa(
to provide wide bitches on each sid
and to raise the roadbed a little highe'
than the surrounding country. =
After proper drainage has been Sc
cured the roadbed should be crowned
beginning neal the source of supply .
the clay or sand. The clay should
then be spread to a depth Of from 81!
to eight inches in the center, slopins
off gradually to a thin layer at tn
sides. Upon the clay should be places
a thin covering of sand. If the ella.
is of the plastic kind it will then b
necessary to plow and harrow 1t, ad
vantage being taken of rains to puddl
the surface with a disk harrow. SAM
should be gradually added until tn
surface Of the road ceases to ball an
cake.
If the clay is placed on sand to
depth of six inches a cubic yard 0
clay will cover ffty-four lineal feet
consequently a sixteen foot road trea1
ed in this manner would require on
cubic yard of clay for each three fee
Of length. A mile Of sixteen foe
road would therefore require 1.7G
cubic yards of clay.
If the clay subsoil Is to be treate
with sand it should be plowed an
narrowed to a depth of about fou
inches. On this prepared subsurfac
should be placed from six to eigt
, inches Of clean sand, spread thickes
at the center and sloping to the side
in much the same ann as the ella
, Is applied to a sand road. These N;
terials should then be mixed dry il
stead of the wet mixing, which
preferable when clay is applied I
, sand. This is preferable because til
clay a be better %pulverized when !
t a dry state. After dry mixing the roa
5 should be puddled following the frs
j., heavy rain. When the materials al
!, thoroughly mixed and puddled a roa