The Manchester journal. [volume] (Manchester, Vt.) 1861-current, 1913-02-06

frsdaeea w 90 frani wtesis aSt that
tsatleaay sbs ~afim aswufiianrs q
az rssa /, prs5Bord - tks rear -
sfssauf uhsvit u TIE erss srfs pro
duo1 D. sufgies ~ fscu@m to sfftsh
"a t.afh fiegs sna rear pH~ris shaNs
- seassev aai stmiiHF Al ieasi u 'eeins
sp,amBi a. ibc wF1trt. tbTfeiose, that
ths road l.rs 20 pied ~ ssea@f uasie
~ ihe nsaa wiAeb npi tssi frfi@ ihls
powrfful tfaFate shnas y har asrsaay
h.-ea drmonafuts8 ihsi as i,iuin usae
sasn rad u oalabig q resisting ihls
iagv.
TbF EFFORTS n progressive highway
eugiseeFA are thps directed isimaff
.y toward the preservation u orr sl0ns
surfaced nssds and the cuasstacileu q
dnsilcva rasds 81 toe ase q a nipaet
more luweriui than stone dUH aud
-ersndiy. 10 mlnlmiEing o. nitigHitng
las dust nuiaaBcc
po lhe i.urrose o' discuHslng inielh
reuslg the experiments thos faf sua
Quoted with sleeisi flinders The term
-dum pretsnufes has teen applied
Ia 90 of the ysnoas binders having for
tbeif uain objeCt either suppression or
toe prevention Of dust These may b.
aivided into two classes. Temporary
and permanent The TEMPORARY biDders
serve merely As pnllistives and require
frequent renewal The permanent bind
ers. - called. enter Into the structure
" the rUad A. Constituent element
and are either Incorporated with the
other materials 81 the time Of the con
aructioh OF applied later by surface
Treatment
10 the class Of temporary binden
may BE- included water. salt solutions
light otis Bnd tars aud oil and tai
emuisluns waste sulphite liquors. etc
while the permanent binders include
ihe heavy pctr0ieums aud tars, pitches
aud numerous oil, tar and asphalt prep
arations. The value Of salt solutions
which haye been used 10 some extent
lies IN the microscopic character OF the
dissolved salt. which. having consider
able aiiiBity for water, keeps the road
surface in . moist condition long after
a surface treated with water alone
would have become dry through eyapo
ration
The light oils and tArs ms well as the
oil aud tar emuisions depend for theif
effect upon comparatively small
amount Of true binding base left upon
the road surface after the volatile
products have evaporated These INA
terials prove effective only so long AS
they retain their binding power. When
the binding power Is destroyed II Is
necessary TO apply more material,
The heavy oils aud tars differ from
the lighter products In that they con
tain q much greater amount OF trut
binding base The results are, there.
fore. OF more lasting character ant
hence the name permanent binders
The semisolid aud solid preparations
usually contain a still greater amount
OF binder With some few exceptions
al OF the true binders are bitumens,
Tie usual method Of applying these
materials 10 the road surface Is by
sprinkliug. The temporary binders can
usually be applied cold. but the perma.
uent binders because OF their much
greater yisc0sily must be heated until
sufficiently nuid In England and
France the use Of coal tar Is practiced
TO large extent, and their methods OF
application have been highly developed
7 Machines are Ia general use which are
self propeling and In which the tar IL
( heated aud applied TO the road surface
as a spray under high pressure Ihest
SO called tar sprayers" are not only
Z very economical In the use OF tar, but
I insure a more even distribution aud
I letter penetration of the road surfac.
than il Is possible to obtain 10 almost
any other way
I In the construction OF dnstless roads
I the crucial question is that OF cost The
/ effort must be TO develop form OF
/ construction which will withstand fast
automobile traffic aud at the same time
| be within the financial resources OF the
community This Is largely being done
az present 10y the use of bitumlnous
/ binder instead of rock dust The two
methods generally employed are known
~ the penetration and the mixing
methods. In the former the hot liquid
+ binder Is sprinkied or sprayed over the
4 stone and allowed TO penetrate through