Concrete Roads
and Their Construction
År: 1920
Serie: Concrete Series
Forlag: Concrete Publications Limited
Sted: London
Sider: 197
UDK: 625.8 Con-gl.
Being a Description of the concrete Roads in the United Kingdom, together with a Summary of the Experience in this Form of Construction gained in Australia, Canada, New Zealand and the United States of America.
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IN THE UNITED KINGDOM—PROVINCIAL 49
the reason ; so that it was thought that, all things considered,
the position would give an excellent test of the possibilities of a
reinforced concrete road.
Owing to the absolute necessity of keeping the road open to
traffic, the length was treated in two portions. The width of
the road between kerb lines was from 24 ft. to 26 ft., and as the
width of the reinforcement was 7 ft., a 14 ft. width for the length
of 300 ft. was dealt with first, thus leaving the remaining width
open to the traffic.
The following specification was adopted :—
“ The thickness generally to be 6 in., laid in one course, with
the reinforcement placed about 2 in. above the bottom of the
concrete. The concrete to consist of one and a half of 2-in. local
limestone, one and a half of 1-in. stone, one and a half of
coarse sand to one part of cement. Transverse joints not to be
provided, but a longitudinal joint to be formed along the whole
length between the two portions of the road as laid. A strip of
thin tarred felting to be placed against the finished portion as
the work of laying the remaining portion proceeded ; thus the
two lengths would be absolutely independent of each other.
Where the concrete butts the kerb a clay joint of about | in. to
be made on both sides. At the end of the day’s work an additional
strip of reinforcement 3 ft. wide to be built into the last portion of
the day’s work about 2 in. below the top of the concrete, leaving
18 in. of the 3-ft. width projecting, in order to help the bond
with the next day’s work. When completed the road to be
allowed to harden for at least three weeks before opening to
traffic, tbe surface being treated with tar and grit at the end
of this period.”
After the work of scarifying and removing the old macadam
surface had been carried out to the required depth, the founda-
tion, which was not any too good, was well rolled by a 12-ton.
roller and made up in a, few sunken places with hard, dry
filling.
Laying of Concrete.—The work of laying the concrete was car-
ried out exactly as specified, but it was found difficult to do this
economically owing to the somewhat confined space caused
through the necessity of keeping the one part of the road free
for traffic. .
Before spreading the concrete the foundation was saturated