The evening times. [volume] (Washington, D.C.) 1895-1902, 1900-01-17

little methane. and practically nothing
else
Il have ascertained by experiment that
one part by volume of asphalt cement will
absorb forty-twO parts OF Illuminating
gas in somewhat over a month. / have
also practically shown that asphalt Is
much sOftened by absorbing gas. the Ordi-
nary asphalt cement becoming as soft as
a thick maltha after being in an atmO-
sphere of Illuminating gas for several
months. As to the quantity of gas con-
tanned in the affected pavements, this Of
course varies, but in one instance 1000
c. C. Of pavement gave Off 500 C. c. of gas.
Must Stop the Leak.
There is but one way to stop the dis
Indignation OF a pavement from this
cause. and that is TO stop the leak Of gas;
for it is useless to patch the pavement.
as it will not be long before the patch
disintegrates. / have known OF cases
where a pavement so affected was re-
paired and in fourteen months the patches
were showing signs OF disintegration-
''Disintegration by water entering
pavement by oozing up through the base.
/ believe If more thorough investigation
were made into the cause for the disinte-
grating of pavement. this would be found
70 be one OF the most common, especially
in small towns and cities where there are
terraces or considerable lawns In front Of
houses There have been a number OF
cases in this city where the water has en-
tered terrace or parking where they were
above the grade OF the street and worked
its way up through the concrete base 10
the asphalt surface.
This disintegration manifests itself diff
ferenuy, depending on the character OF the
pavement. II the asphalt surface is soft
or the concrete smooth. the first defect
noticed Will be the tendency OF the pave
ment to crowd in warm weather. This Is
due 10 the under portion OF the surface
mixture rOtting so 10 speak. thus destroy
ing the cementing properties of the as
phalt. The upper portion although good.
being deprived Of the support OF the az
fected mixture under IT, will be crowded
out by traffic. This crOwding is assisted
by the concrete base being smooth. and also
the bond between the base and binder are
destroyed by the moisture.
Result OF investigation.
IN cases where the concrete base Is
rough and the surface mixture hard, the
principal disiHtegratiCn will take place in
cold weather. nothing abnormal being no.
ticed until the pavement begins a rapid
crumbling away in the affected spot under
traffic.
''On examining a section OF asphalt sur
face disintegrating from this cause. espe-
/ cially where IL has not been going on for
too long time, there viii be found a layer
Of perfectly sound and good material at
the surface Of the pavement. while under
meath the mixture win show evidence OF
being disintegrated by water-that is the
sand viii appear clean and white ia spots
as though there had been an iusufficiency
Of asphalt cement TO cover IT, The concrete
base under the affected pavement will gen.
u snNT Ia 10. Il
have prevented the destruction Of several
Davemeuts from this cause by the use OF
blind drains put in under the gutter next
/ 20 the lawn or terrace and even run her
ringbone under the pavement
This last cause for disintegratiOn would
/ OF course not occur in a pavement con-
/ structed with an asphalt that was Enacted
on by water. but water soaking up through
I a concrete base might iuiure any pave
ment by freezing.
/ 1t is always advisable where n pavement
shows signs Of disiutegrating TO examiu.
/ into the cause In a most careful manner
. and not pass snap Judgement. II. seems Ouly
/ too easy fer the majority OF people wheth-
/ er experienced OF not, to place the blame
for the failure OF pavement on the manu-
; factu-ors. / have heard men with c5nsid-
/ cradle experience commenting on a bad
I place IN a pavement that they did not care
fully examine, remark 'Jhey used bad oil
. or asphalt In that piece OF work They
. have not taken into consideration that al
. but possibly square yard OF the pave
/ meut is in good condition. and that IL would
I be no economy 70 a contractor to use
I bad material in one small place OF the
Z pavement. \ careful examination into tho
. disinteGratirg Of q pavement may in mauy
/ cases. show a cause that IS entirely for
| eign to the composition Of the materials
/ and q cause that could be easily remediel
; with li.tle common sense