Greene County herald. (Leakesville, Miss.) 1898-current, 1913-01-24

produced by the front wheels and that
practically the entire disturbance OF
the road Is produced by the rear or
driving wheels. 1t the effect were pro
duced by suction or vacuum the action
of both front and rear wheels should
be somewhat similar at least. 1t seems
apparent to the writer, therefore, that
the road best adapted to motor traffic
Is the road which will best resist this
powerful tractive shear. It has already
been demonstrated that no plain mac
adam road is capable of resisting this
force.
The efforts of progressive highway
engineers are thus directed primari
ly toward the preservation of our stone
surfaced roads and the construction of
dustIess roads by the use of a binder
more powerful than stone dust and
secondly, to minimizing or mitigating
| the dust nuisance.
For the purpose of discussing intelli
gently the experiments thus far con-
Quoted with special binders the term
| dust preventives" has been applied
| to all of the various binders having for
| their main object either suppression or
the prevention of dust. These may be
and permanent The temporary binders
serve merely as palliatives and require
frequent renewal The permanent bind
ers, so called, enter into the structure
of the road as a constituent element
and are either Incorporated with the
other materials at the time of the con
struction or applied later by surface
| treatment
In the class Of temporary binders
may be included water, salt solutions,
| light oils and tars and oil and tar
| emulsions. waste sulphite liquors, ETC..
while the permanent binders include
the heavy petroleums and tars. pitches
and numerous oil, tar and asphalt prep
arations. The value of salt solutions.
which have been used to some extent.
lies in the microscopic character Of the
dissolved salt, which, having consider
able affinity for water, keeps the road
| surface in moist condition long after
| a surface treated with water alone
would have become dry through evapo
| ration
| The light oils and tars as well as the
oil and tar emulsions depend for their
effect upon a comparatively small
amount of true binding base left upon
the road surface after the volatile
products have eyaporated. These ma
terials prove effective only so long as
they retain their binding power. When
the binding power is destroyed it is
necessary to apply more material.
The heavy oils and tars differ from
| the lighter products in that they con-
| tain a much greater amount of true
! binding base. The results are. there
fore. of a more lasting character and
| hence the name permanent binders
The semisolid and solid preparations
usually contain a still greater amount
of binder. With some few exceptions
| all OF the trum binders are bitumens
The usual method of applying these
materials to the road surface is by
| sprinkling. The temporary binders can
usually be applied cold, but the perma-
nent binders because of their much
greater viscosity must be heated until
sufficiently fluid In England and
| France the use of coal tar is practiced
| to large extent. and their methods of
application have been highly developed
Machines are in general use which are
self propelling and in which the tar is
heated and applied to the road surface
as a spray under high pressure These
so called "tar sprayers" are not only
very economical in the use of tar, but
insure a more even distribution and
better penetration Of the road surface
! than it is possible to obtain in almost
any other way.
In the construction of dustless roads
the crucial question is that of cost. The
effort must be to develop form of
construction which will withstand fast
automobile traffic and at the same time
be within the financial resources of the
community. This is largely being done
at present by the use of bituminous
binder instead of rock dust The two
methods generally employed are known
as the penetration and the mixing
methods. In the former the hot liquid
binder is sprinkled or sprayed over the
stone and allowed to penetrate through