Western Carolina Democrat and French Broad hustler. [volume] (Hendersonville, N.C.) 1913-1915, 1914-10-29
SAND-CLAY ROADS.

RAS - IACO1ya Inc CLOSELY packed nara
grains of sand are held securely in
place by the adhesive properties of the
clay. Each grain is covered with a
thin linn of clay and all the voids COM
pletely filled. The ideal theoretical
mixture for a sand-clay road is what
the mason calls a dense, well-graded
mortar. Sometimes we can choose our
materials SO as to comply very closely
With the theoretical requirements.
While at other times we can only do
the best possible with such materials
as are available. Sometimes either
the sand or the clay may be such that
II would be a waste of money and eff
fort to attempt to build sand-clay
roads.
The sand must have body enough to
sustain the wear of the traffic. Some
SANDS are too fine and rounded to be
or much value in road construction.
The ideal sand is sharp and coarse
the largest grains about the size of a
small pea and graduated in. size down
To about the size of a pin head, free
from dust and organic matter. 1t will
often pay to haul such sand several
titles, rather than to use a fine round
ed or loan sand from nearby deposits,
Do not make the mistake of thinking
that the most easily obtainable sand is
always the one to use.
Before beginning construction ex.
anime carefully all the available sand
deposits in the light of the above given
definition, and choose the best, consist
emit with reasonable cost of hauling.
A day spent in such investigation may
mean the difference between success
and failure of the road, or at least
the. difference of years in it's life.
No matter how good the sand is, the
road will be a failure unless a good
clay is used for binder. First of all,
the clay must be sticky and tough, so
that it will hold the grains of sand
firmly in place in dry as we'll as wet
weather. A clay that crumbles readily
when dry will make a dusty road in dry
weather and one that takes up water
too rapidly will become muddy in the
rainy weather. Furthermore, the clay
must be stable, that is, it must not ex-
pand or contract with varying amounts
Of moisture. You can readily see that
a clay which expands or contracts
much will not make the most desirable
binder, a changes in volume will tend
to, displace the grains of sand and,
consequently, destroy the bond.
In actual construction the question
CT making tests usually resolves itself
into choosing between a few available
materials. Rapid and very satisfac
tory field tests are made as follows:
From typical samples of both sand and
clay mixtures, varying by one-half
part, are made to cover a range of
from one part sand and three parts
clay, and worked up with water into
d putty-like mass. From each mix
equal quantities are taken and rolled
between the palms of the hand into
reasonably true spheres and placed in
the sun to dry.
When thoroughly baked the spheres
are placed in a fiat pan or dish and
enough water gently poured into the
pan to them, care being taken
not to pour the water directly on the
samples. Some samples will begin to
break down Immediately. Those
breaking down most slowly contain
most nearly the proper mixture.
Sometimes the sand and clay is
found already mixed in the proper pro-
PORTION in nearby fields. Then 1t is
only necessary to haul the material
and spread it on the road, and either
compact it with a roller or leave it to
be compacted by passing traffic. Roads
constructed with such material are
generally termed top soil roads, al
though there is no fundamental differ
ence from the regular sand-clay road
excepting mere details of construction.
Having selected the materials to be
used, the next step is to prepare the
roadbed for their application. The
frs. essential is to have the road plo-
rely located and such grading 'one
as is necessary to eliminate or reduc !:
steep grades, sharp turn, dangerous
railroad crossings, etc. 1t is worse
team folly to put expensive %surfacinS
on a road with excessive grades or
poor location, where these can be
readily reduced before the surfacing is
done.
The second step is to provide the
| proper drainage for the road and to
shape the roadbed. The drainage for
a sand-clay road should be just as eff
| cient as for any other type Of road. !.
In general practice only the clay is
| ADDED on a sand road, and the sand on
a clay road. One or the other Of the
essential materials is used as it may
be found in place on the road. In
| some cases it would no doubt be pre-
ferable from the standpoint of true
economy to select and haul both the
sand and clay, and SO secure a much
better road surface.
In construction On a sand founda-
ton the proper drainage is first pro-
vided, and then suitable clay hauled
and spread on the road to a depth OF
about six inches at the center, taper
ing towards the sides, and of such a
width as may be desired. For ordi-
nary country roads sixteen feet is
usually sufficient. In the best finish
ed sand clay road we find the follow
ing proportions: sand about two