, 1876-02-06
STREET.PAVEMENTS.

Gen. q. A. GILMORE, who distinguished
himself in the late War, has contributed to
| the New York Tribune an. elaborate article
| on streetpaTements in large cities. The
| subject is treated in scientific manner, md
furnishes much information that may serve
as guide to Municipal Governments upon
this very important subject. Gen. GnMcsE
asserts that the essential requisites of good
street-payement are: l, that it be smooth
| and hard; 2, TINT it furnish foothold
for animals, and not become polished
aud slippery; 3, that it be noiseless
and free from dust and mud; I, that it be
capable OF thorough cleaning; 8, that it be-
Of durable mnteri2l, and Of such construc-
tion as to be easily taken up orrelaid in places;
6, that it bo easily repaired at all seasons and
at moderate cost Roads of broken stone and
gravel, though comparatively noise1ess, fur
nish dust and mud, and are not adapted to
the heavy travel of cities. Cobble-stone
pavement is condemned Us far inferior in
every respect to stone blocks, though these,
if laid on sand, rapidly form into ruts.
Indispensable to oil paved streets is good
foundation, and to the absence Of such foun-
dations is attributed the failure of all forms
Of pavement in cities. The suitable founda-
hons for street-pavements are stated to be:
l, hydraulic concrete, to inches in thick
ness; 2, rubble-stones set on edge, but not
in contact, with the interstices filled in with
concrete 3, rubble~stone set in contact, on
edge, like the sub-payemenr Of Telforl
road; 4, cobble-stones firmly set in form of
sand or gravel; s, small rubble-stones of
random sizes in weu-compacted layer
6, layer OF broken stone laid in the man
ner of macadarized road. OF these, the
first, second, and third are considered the
Having secured these foundations, tho rela-
tive value Of stone blocks, wooden blocks,
and asphalt for the pavements are considered.
Of each Of these general kinds Of pavement,
the best stone pavement is one composed of
rectangular blocks, set on their longest edge
ncross the street, upon concrete foundation.
The best wooden pavement is one of rectan-
gular blocks, set On their edges across tho
street, on a suitable foundation, for which
none Of those mentioned are good, because
wooden blocks would not endure the crushing
they would receive if set on hard, inelastic
foundation. A good asphalt pavement re-
quires firm foundation. The asphalt may
be of the natural asphalt rock, obtained from
Switzerland, or it may be that composed Of
asphaltic cement, prepared by refining the
natural bitumen, to which is added calcare-
GUS powder to take the place of the amor
phous carbonate Of lime found in the natural
asphalt rock.
Gen. Gu4MoRE says that there is distinc-
ton between pavements Of genuine asphalt
and the patented limitations or substitutes
composed Of wood-tar, coal-tar, de-, mixed
with sand, ashes, scorin, &C., sc. AL Of
these mixtures he pronounces unfit for car
riage-ways. The advantages Of a good ns-
phalt pavement are that it produces no dust
and no mud; it is comparatively noiseless;
it does not absorb and retain no1ious liquids;
it is impermeable to moisture, and neither
emits nor allows the emission from the SUBJ
soil Of unwholesome and poisonous vapors;
it reduces the force Of traction to minimum.
Though it does not give as secure foothold
for auinals as stone or wooden blocks, it does
not become polished and slippery from COZ
tinued wear. Il is adapted to all streets not
sleeper than in so, except those that
NV thickIT crowded with heavy loads, ss In