Concrete Roads
and Their Construction

CONCRETE KERBING 173 Concrete has been much used in Brighton. The wall at the south side of Marine Parade was built in lime concrete by a local builder in 1830-1834. This wall, in places, is 50 feet high, has a batter on the face of 1 in 6, is 2 ft. thick at the top, and the back is vertical. This cost about £100,000. The first cement concrete groyne for sea defence was built in 1865, and at the present time all the wooden groynes have been removed and concrete groynes substituted. Surrey.—Mr. Alfred Dryland, M.Inst.C.E., Jate County Surveyor of Surrey, now of Middlesex, has furnished us with the following interesting details and illustrations of the method adopted by him :— The first kerb put down in Surrey was a reinforced concrete submerged retaining wall or abutment to the carriage-way, and was evolved from considerations of, and investigations into, the apparent weakening of the road crust at the sides by movement or “ creep ” in the cross-fall direction, where the roadside wastes were soft or the ditches unpiped, and was primarily intended to remedy such defects as arose from this cause. The kerb was laid in situ and was 9 in. deep by 4 in. wide and reinforced with two steel rods | in. diameter in the positions shewn in Fig. 123. The kerb was put down to levels to coincide with the finished top or carpet coat of the carriage way when laid. A trench 8 in. wide was excavated to required depths and 9 in. by 2 in. deal shuttering held in place with iron road-pins was fixed in proper position four inches apart. Concrete composed of four parts clean crushed ballast to pass half-inch mesh sieve, two parts clean sharp sand and one part British Standard Specification Portland cement (all measures by bulk) was deposited between the shutters and tamped and trowelled off on top and the reinforcing rods inserted in their proper positions as the work proceeded. The shutters were painted with soft soap and were allowed to remain for three days, when they were removed without difficulty and with- out detriment to the concrete kerb, which was immediately cov- ered over with a small mound of earth and left to set for at least 28 days. Where the ground was sufficiently deep and compact and could be cut in a straight regular face, no shuttering was used on the back face. At bends or curves in the road 9 in. by 1 in. shutters were used to obtain an easy sweep. The kerb was con- tinuous and being practically submerged, and therefore not liable to great changes in temperature, no expansion joints were con-