Evening star. [volume] (Washington, D.C.) 1854-1972, 1880-10-30


100 100
The specifications Of last year called for IS to
20 per cent OF asphaltic cement, but experience
showed that this proportion made the pave
ment too soft In summer, and the proportion
actually used was between 16 and II per cent
At nI present cent, the proportion used is about
masonry practically u impe peril a ann
comparatively thin and smooth wear
ing surface. which can be replaced when it is
crete base Is easily made and satisfies all the
conditions; in making the wearing surface
there are many practical difficulties which re-
| quiTe constant attention and skilled expert
| enced labor. The pavement Is subjected to
| temperature OF $50 degrees In summer and 10
degrees In winter, range OF 100 degrees Fahren-
belt, at all OF which temperature &c Is required
! to present a uniform surface. The danger In
practice Is that In extreme cold the surface will
crack and become friable, and in extreme heat
| under the traffic and present wavy surface
! very uncomfortable TO travel over. Refined
asphalt is very brittle at temperature of 60
degrees Fahrenheit, or less; when tempered
| with the heavy Oil, resulting from petroleum
dstillation, IL becomes ductile and tough. but If
the heavy Oil Is added In eHcess-say above 20
| temperature OF $50 deg. or even less. The
| problem is therefore to mix these two hydro
n such no hat the mixture
| extremes OF cold and heat actually experienced
on the streets; Up to che present time the pro-
poron ION OF OH mas Den Kept at about ~ 70 100 or
| 1873 have cracked under the cold minimum 5
| Fahrenhett OF the two winters since that date
few OF them have In two or three small places
| crept into waves under the heat OF summer, as
In spite of all precautions mistakes Will some
times occur In the preparation or handling of
the material. The mixture of asphalt &: e.
| mineral bitumen) and petroleum oil is the
cement which binds together the particles OF
sand, which forln 3 of the wearing surface and
IT'S re F eno;,o Ia m Ths
In the sand, and only enough 10 bind them to.
gether when perfectly compressed. In order to
aos v0d lime as stone ms'n powder as POS IS
added to The sand In the proportion OF about 1
70 4. The powder is OF such degree OF f1neness
OF 1t will pass q 40 screen. The cement, as pre-
viously stated, is added in The proportion OF
about Is to So OF sand and limestone powder
combined. The oldest pavement of this class Is
the one laid by the paving commission of 1Sf6
on Pennsylvania avenue, between 9Th ard 18th
streets. This has now been on the street be-
made at the expense of the contractors are
understood to have cost s. 1880, or at the rate
Oh sIl4;l6 per arnum. The number of yards
being So, 1850 the annual expense for repairs
has been less than \ cents per square yard
On the compressed asphalt pavement laid by
tne Neuchatel Paving Company on Pennsylva-
pairs are reported to have cost about ST. S6I or
S622.33 per aDnum. The number OF yards
being 25, 1926, 2s-100 the annual expense for re-
pairs has been about ~ cents per square yard.
This pavement OF the Neuchatel company Is of
the same character as those laid on the road
ways In Paris. 1t Is composed of natural Bit
luminous limestone, which Is broken and reduced
TO powder by heat, placed on the street In form
OF powder and compressed by large iron ram
mers The paVements which are now laying In
THIS city, under the name OF asphalt, are drtt-
tcidl mixtures or mastics. Our Investigations
and practice are therefore On an entirely diff
ferent line from those in Paris. The objections
made to the Paris pavement are we'll known to
be its slipperiness during light rain or In damp
weather, and the difficulty OF cleaning. The
contracts Tor maintenance provide for sand
ne when slippery and for
scrubDlDg with rubber mop or ''Squeegeen In
order to clean it. The same objections apply to
inc compressed asphalt pavement on Pennsyl-
Vania avenue; While the mastics as laid here are
Almost Tree from these objections, owing TO the
gritty nature OF the sand, which forms large
!" of sr Oh sne ingredients; Is to- soon as yet
me masiics. When cut by plumbers for making
connections with pipes and sewers, the surface
payementS are all to be repaired at the CONTRACT
tors expense during the period OF five years
from date OF completion, but as yet no repairs
have been necessary except for cuts made by
| plumbers
The entire surface of asphalt pavements, on
concrete base, In this city On the lSt OF Janu-
airy, 1881, Will amount 10 100000 square yards;
or the O-caled concrete pavenentS, OF which
the cementfDg substance was produ Il of coal
Tar, the amount is 600 square yards; giving
total OF 1,O5o,000 square yards of Inonolithic
or snOOtn surface ravefnents. extending over a
iehgth or IL miles This Is considerably more
than exists on the roidways OF all other ctties
10 the world taken together. the amounts for the
cities being as follows: Paris, $4,000 square
yardS-l954 miles, London. Isl, 900 square yards
on miles; New York, 900 square yards-1
in1le; Other cities, (eStlmated). $4,000 square
yards-2fl miles, total OF 680, 900 square yards
or 80 miles.
TEE CONCRETE PAYMENTS"
The sO-caled concrete payementS are, as
general rule, In a fair state OF preservation.
They were generally laid On base OF broken
stone from to inches thick, covered with a
layer OF 'binder" about inch thick, composed
OF pebbles and cement OF coal tar. The wearing
surface was made 1n various ways, according 20
the patent, but consisted essentially OF small
gravel, sand or stone dust cemented by a pro-
ducJ OF coal Tar. In The later pavements of this
variety certain proportion OF asphalt was
mixed with the coal tar and With beneficial re.
suits. Several or these pavements have stood
me TEST OF nVe years wear with little or no re-
PAIRS, ana are to-day In perfect condition:
others were OF inferior qualify Where the ton
surface has worn OFF, these Da vements Begin n
70 70 pieces very rapidly, and IN order to save
tnem nom destruction they must be promptly
covered with new wearing surface,
during tne year lSi9-SO, So, i36 yards were thus
desurIaeeo, ana II 500 yards were entirely con-
ueHned, taken up and replaced with the stand.
ara asphaltum pavement on a concrete base.
during the current year about Is 900 wards
1-'O uccu llaCeu OF are under contract.
experience has, however. shown that by care
lul attention and constant repair of small
quantities In each, these pavements can be
made TO last much longer than Was Anticipated
PaVementS, for example, which seemed on the
point OF destruction two years since have by
constant patching been maintained up 10 the
present time and still present good surfaces.
These payeIne ats, however, were all laid within
few years OF each other, and there Is a possi-
biity that after few years more OF wear they
might all break up at the same tine-during a
severe winter, for example. IL Is therefore,
economical TO gradually resurfac5 certain
portion every year, aud an appropriation OF
ABOUT $4,000 Should be made ANNUALLY for this
purpose.
IA table is given here showing that there was
land from 1871 TO 1915 al, AIS square yards at a
cost or 81, 2S4 ,O04 81, On which there has been
expended for reSurfacing and minor repairs
since 1878, $44s, 152.03.l
These repairs extend over period OF seven
years; Z. e, from lSI3-the average time OF
laying-to 1880 and the average annual expense
OF repairs is therefore SOL 026--or at The rate OF
So cents per yard. This is certainly not an ey-
pensiye rate for the luxury OF smooth pave
ments. The asphalt pavements being composed
OF less perishable materials and being laid in a
more substantial manner, 1t may be confidently
expected that the cost OF maintenance Will be
still less
The minor repairs of concrete and asphalt
paveneLtS are made by contract let to the low
est bidder and running for one year. These
repairs include the damage done to payementS