Reporter and farmer. [volume] (Webster, Day County, Dakota [S.D.]) 188?-1946, 1912-08-01
R~oadmaking in
North Dakota.
BY H.. L. Hard, GeoIogIst,
North Dakota Agricultural
College.
r + i. J. +

While In n sense of the word
North Dakota may be poor in road.
making rock, on the other hand, she
IL exceptionally fortunate in having
thousands of miles Of natural sand
clay roads of low gradient.
Nature has generously deposited In
the central two-thirds of the state clay
saturated with sand, or so nearly so,
that 1t requires but a small per cent
to be added to make II so. Sand clay
roads are the coming roads. Little is
known Of a~rtiHcialiy constructed ones
in North Dakota. but as a matter OF
fact We are using many miles Of those
nature has made.
In the experience OF the federal ex-
perts, and of the local authorities in
many places, especially in the South,
Ia eand clay road construction is be-
yond the experimental stage. They
have proven a great success and in
the South are for some purposes con-
sidered superior TO macadam.
If an obstruction equal to 4 per sent
of the wheel radius increases draft
over twofold 1t is imperative that adj
vantage be taken Of every available
road material A concrete
example Of the resistance OF poor
roads Is een in that an obstacle 90
inches high is 4 per cent of the radius
OF a forty-eightinch wheel, or In other
words, an ordinary wheel blowing up
a bne-inch rut more than doubles its
draft. The g~eologist leaves to the
engineer the development Of such
vital problems. as well as such facts
as that a given force pulling four tons
on macadam pulls but one ton or less
on muddy road. Where rocks for mac
adam are lacking sand clay offers a
cheap substitute and reduces the draft
70 one-third Of ven one-fourth of what
it ia on the average earth road, as
careful time tests show.
In initial cost the sand clay road ap-
peals most strongly. being on the av-
erage about one-sixth of that OF mac
adam. Many such roads cost about 8
cents per square yard. or $500 30 $500
per mile, as against $1,000 to $4,000,
depending on ansunt OF stone added
and many other factors, In the mac
adam type.
The principle Of the sand clay Is
simply that Of adding either clay or
sand to the graded roadbed, deficient
in either. until the sand is at the point
called ~saturation. which is explained
az being in the state where the angu-
lar sand particles are abundant enough
to readily touch and give bearing sur
faces when worked under wheel and
hoof. Simple experiments a deter
mine this correct mixture, which any
one can work out. The sand must be
sharp and angular, as rounded grains
slip ove one another and make a o
bed. Again. the clay content must be
great enough TO I'LL the voids between
the sand and act IS q binding materi-
al. The problem In such heavy clay
soil areas az the Red River valley is
than In very sandy areas, as
It IL naturally cheaper TO handle sand
If applying II to q clay coil than to add
clay to a sand soil. Pudding or init
mate mixing Of the two substances
must follow. This is sometimes done
at considerable expense OF
may be left for travel & accomplish.
Where the natural road site constt-
the bulk Of the constructive ma
terial, the question of material and