The Bossier banner. [volume] (Bellevue, Bossier Parish, La.) 1859-1952, 1912-08-22
prod aced by the front wheels and tha

prod aced by the front wheels and that
practically the entire disturbance OF
the road is produced by the rear or
driving wheels If the effect We're 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
been demonstrated that no plain mac
adam road is capable of resisting this
force.
The efforts of progressive highway
engineers are thus directed primarf
iy toward the preservation of our stone
surfaced roads and the construction Of
dustless reads by the use of 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 preyentives' has been applied
to all of the various binders having for
their main object either suppression or
the prevention of dust. These may be
divided into two classes. temporary
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 constituent element
and are either Incorporated with the
other materials at the time of the con
struction or applied later by a 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
|
a surface treated with water alone
would have become dry through evapo
ration.
The light oils and tars as well as the
Gil and tar emulsions depend for theil
effect upon Il comparatively sinai
amount of true binding base left upor
the road surface after the volatil,
products have evaporated. These ma
terials prove effective only so long Il,
they retain their binding power. Whel
the binding power is destroyed it i
necessary to apply more material.
The heavy oils and tars differ from
the lighter products in that they con
tain much greater amount of tru
binding base, The results are. there
fore. of a more lasting character ant
hence the name permanent binders.
The semisolid and solid preparation
usually contain still greater amour
of binder With some few exception
all OF the true binders are bitumens.
The usual method of applying thes
materials to the road surface is b.
sprinkling. The temporary binders ca
usually be applied cold. but the permH
nent binders because of their muc
greater yiscosity must be heated unit
sufficiently fluid In England an
France the use of coal tar is practice
to a large extent. and their methods Q
application have been highly developed
Machines are in general use which ar
self propelling and in which the tar
heated and applied to the road surfac
as spray under high pressure Thes
so called tar sprayers" are not onl
very economical in the use of tar. b'
insure more even distribution an
better penetration of the road surfac
than it is possible to obtain in almo>
any other way
In the construction of dustless road
the crucial question is that of cost III
effort must be to develop a form c
construction which will withstand fas
automobile traffic and at the same tin
be within the financial resources of til
community. This is largely being d"'
, at present by the use of Il bituminou
binder instead of rock dust fhe tW
, methods generally employed are know
, as the penetration and the mlAlil
!, methods In the former the hot liqul
: binder is sprinkled or sprayed over Il
: stone and allowed to penetrate throuG
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