Five Mile Beach weekly journal., 1921-10-28

more, and have any bituminous pave
ments, rel the highest type, sheet
asphalt, when subjected to heavy traf-
hc, given any such indications? With
few exceptions it is the opinion of the
writer that they have not.
For proper financing it seems a fun
damental fact that the roads should
be constructed, in the first instance,
from the general funds, and should
forever thereafter be maintained from
current receipts, even though that
maintaining requires r%esurfactng, or
even rebuilding. Amy course other
than this will lead to ruin. If the
funds from motor vehicles are used
to float bond issues, the maintenance
fund is cut off. On the other hand,
if the general fund is used for main
tenance, it will eventually bankrupt
the government.
Concrete Considered Best Construction
The principal form of construction
now being used, and in the opinion of
tn ewriter the very best, is cement
concrete; but it is best because it is
going to give a long life at low main
tenance, and by long life the writer
means from 10 years, on very heavy
traffic roads, to Is or 20 years on mod
erately heavy traffic roads. When it
reaches the point where it no longer
can be economically maintained as a
concrete road, it can be resurfaced
with some form of god hot mixed BIZ
luminous pavement to give another
period of long life, conserving the en-
tire initial investment, instead of hav-
ing to be 'junked," as has been the
experience in the past with many
b~roken-stone roads, whether con-
structed as water-bound macadam or
as bituminous macadam.
Maryland is now confronted with the
problem of resurfacing some of its
earlier concrete roads which have
given satisfactory yea for a period
ranging from Z to 10 years. During
1913, the commission resurfaced 2.8
miles of the Baltimore-Washington
road, which was constructed partly of
concrete and partly of penetration
macadam, and 1.5 miles of road lead
ing to Camp Meade, which was con
structed of hassam compressed pave
ment in 1914. Further sections of the
Baltimore-Washington road will need
to be resurfaced in 1920, notably the
section through the village of Elk
ridge, 1 mile in length, and the sec
ton from the District of Columbia line
to Bladensburg, 1.5 miles in length.
Failure of the concrete sections on
the Washington road was due for the
most part, not to poor subgrade, nor
to insufficient depth of concrete, but
to the disintegration of the surface.
This dis~integration was such as to
force the belief that it was due to
fatigue" and if this conclusion is
correct, then it is the writer's opinion
that the use of light metal reinforce
ment, or the adding to the depth of the
concrete owe the present depth Of
inches at the side and s inches in the
center, is not going to add materially
to the value of the concrete as a pave
ment. The writer has used the word
fatigue" for the want of a better term
to describe the failure. The disinte-
grafton of the surface appeared at a
number of points throughout a section
simultaneously. At each point of fail
ure the rupture in the surface was
small in size at the beginning, but soon
developed very considerably in size
and depth, which demonstrates that
the actual point of failure is only in
finitesimally weaker than the adjacent
and whole surrounding section, and
when once the surface breaks, the dis
indignation is rapid. If the disinte-
grafton were confined to the top sur
face, it might be claimed that it was
due to abrasion from impact, but since
when a failure occurs, it progresses in
area and depth, it can hardly be at
tributed to abrasion.
Disintegrated Concrete Replaced
These sections of concrete which
showed d~isintegration were entirely
removed and replaced for the full
depth with new concrete struck off
level with the surrounding surface but
when they were opened for traffic, al
most Immediately the surface adjacent
to them began to disintegrate, which
showed that there was no longer very
great resistance left in the adjacent
concrete, and it is believed that it can
be saved only by resurfacing with a
good bituminus pavement. 1t will be
r%esurfaced during 1920 with a stand
ard sheet asphalt pavement, consisting
of ~ inches of binder and 1h inches
of topping.
The question as to when a con-
crete road is worn out" has never
booD da6pito1u oncmorod h1t the fail