The Grenada sentinel. [volume] (Grenada, Miss.) 1868-1955, 1916-03-17
Sand Clay Roads.
BY J. H. DORROH,

BY J. H. DORROH,
Dean of the Engineering Department.
A famous %geologist, commenting on
Mississippi's mineral resources. said
that the sand deposits were her richest
heritage. Clay is more plentiful than
sand, however, and the supply of these
common materials so far exceeds the
demand that we do not fully appreciate
the value of either. The most extern
sive field of usefulness for sand and
clay is doubtless in road building.
1t is a we'll known fact that wet sand
or dry clay will support traffic with
satisfaction, but no meaner roads are
to be found than those of dry sand or
wet clay. Parallel roads of sand and
of clay are at once suggested, one for
wet seasons, the other for dry seasons,
but it is better to combine the two ma
terials into a sand clay road good at all
seasons.
Many failures have resulted from the
improper use of sand and clay in road
building. One a no more build a sand
clay road by dumping one material on
the other and leaving the job, than he
can build a house by throwing some
shingles over a pile of lumber, though
in the case of the road there will be
some improvement.
Stretches of splendid earth roads,
easily maintained throughout the year,
are to be found in many localities. The
material is usually a sandy loan top
soil, low in vegetable matter-a natural
sand clay mixture. If this soil is care
fully selected and spread over clay OF
sand, much good will be done. Surface
ing with top soil is a favorite treat
ment in Georgia and has given fine re-
suits. 1t is only necessary to spread
the selected material over the pre-
prepared road bed to a depth of
six or eight inches, crown with a grader
and let traffic pack it down. Frequent
dragging will be necessary for the first
few months.
To build a sand clay road on a clay
base, the road bed should be graded to
the desired depth and shape; the top
broken and pulverized to a depth of
about four inches with pillow and har-
row or with disk plow; six or eight
inches of coarse sand spread evenly
over the clay and the two materials
thoroughly mixed with a disk pillow and
harrow. The road is next shaped with
d grader and preferably rolled.
On a sand base the clay is spread
about six inches thick; pulverized with
a disk and harrow, crowned with grader
and rolled. Better results will be Sc
cured if the mixing is done while the
road is muddy enough to puddle.
If a roller is not available, traffic may
be allowed to consolidate the road but
more t~tention will have to be given to
maintenance during its early life. A
herd of cattle driven over the road sew
times serves as a good substitute
for the roller.
A sand clay road is not at its best
first completed but must be fire.
dragged until thoroughly con-
solidated by traffic and water. Such a
road, if properly built and maintained.
viii, under average conditions, give
good service throughout the year. and
is decidedly less costly to build and
than a hard surfaced road
The extra cost Of construction will vary
with local conditions but will be from
$500 to $500 per mile. Maintenance
should not cost over 500 to S25 per mile
each year, this amount being spent
mainly for dragging.