Evening star. [volume] (Washington, D.C.) 1854-1972, 1913-06-08

1t cannot be said that ma ca dam roads
in ;lIs country have been properly main
tanned Maintenance has usually been
strongly advocated and little pra cticed.
Maintenance and repair have not been
distinct operations. They are just begin
ming To b, carried as separate accounts
on public records.
Previous 10 about 1905 macadam road
Sisnitied a hroken-stonc road bound with
screenings or fines rolled wet. Such
road is now called a Watel-b bound ordi
marx macadam road. To distinguish il
from roads bound with some bituminous
material which are in turn called bitunni-
nous macadam roads and sometimes tar
red roads OF tarmacadam roads. Or
pitch ma adam roads.
Ordinary macadam roads have until
recently formed the highest class Of i'm
proved country highways Although such
roads are now. in many instances giving
place To bitumnous- macadam other
kinds Of road. they still constitute an inn
portant class of roads and their repair
and ma nt enance involve the fundamental
principles for all road work.
when a road has Worn more OF less
out Of shape in sections and is rutted
new stone is usually required to re-
surface il. The first problem is to de-
The average stone depth the road
may be measured or calculated by
known wear coefficient or by careful
inspection of the general road surface
Accurate measurement Of the stone re-
naming the road cannot he made
by digging a few small holes in the
sur ace. because the subgrade invariably
works into the lower stone. and also
the lower stone layer pcnetrates the sub
grade. a clean-cut trench halfway
across the road Secton) with careful
measurement Will give good determi-
nation. In England. at intervals. GOV
eminent highway bench marks are es-
tabliShed. AT which cross sections are
taken from time to time to determine
the wear Of the surface. An annual wear
coefficient expressed as d fraction of
ton per square yard or as tons per mile
MAY be gradually established for the
various macadam roads under the con-
troll Of each road official ON long un-
evenly worn road. II the estimate OF
new stone is to be formed by inspection.
stations may he run along the center of
the macadam. and against each station
the percentag. of new stone may be
entered. The estimate OF new stone
should he checked by all the informa
ton avala BILE. III particular by actual
measurement AT typical sections and by
wear coefficients OF similar roads
Tho usual method of beginning repair
i To pick up and old road surface with
spikes set in the rear wheels of the roller
and then finish the work OF looSening by
hand by the Of harrow or pillow
The surface must first b. thoroughy
cleaned of dirt and organic matter Me-
chanical sWeepers do the work of sweep
ing rapi>lN and rheaply. Various forms
Of machine scarfierS are also used and
nearly all II them arc operated by a
steam roller. Their essential features are
sufficient strength and ri2idity thoroughly
to break up the hardest surface 1t is de-
sirable that the scaSiier be light enough
IL be removed from the road without the
use Of a roller. Some scarifiers are fitted
with steering devices and the breaking
depths of the spikes can usually be re-
guated These machines cost from 1919
to 500 and are economical if considera BILE
work is 10 he done annually. The cost of