Mechanics of Road-Making Materials

Abstract

MORE than twenty experts in soil mechanics, concrete construction and road engineering have contributed to this valuable record of lectures, dealing with the problem of designing and constructing runways under the great variety of conditions encountered during the War in all parts of the world. A large proportion of the lectures outline various theories of soil mechanics in regard to the capacity of the ground to support load, in order to show how laboratory and field tests can be used to predict the behaviour of the ground under load. Of these, load-settlement curves obtained for small test areas of ground, suitably adjusted for full-scale loading and moisture conditions, would appear to be the soundest method of obtaining safe values of the modulus of soil reaction which, together with the tensile and elasticity characteristics of the concrete, determines the thickness of the latter in the form of a road slab, required to support a given point load. Methods of improving the condition of the sub-grade by drainage, soil stabilization and consolidation are described in detail. A full account is given of the procedure of grading local aggregates and controlling the ratio of water to cement in order to produce the strongest concrete. The use of special devices such as steel mesh tracks on sandy surfaces and blasting in swamps are described, and a whole section is devoted to tar and bituminous surfacing and soil stabilization.

Soils, Concrete and Bituminous Materials A Record of a Course Dealing with Airfield Construction given at the Road Research Laboratory, Department of Scientific and Industrial Research, July-August 1943. Pp. 288.

(London: H.M. Stationery Office, 1946.) 10s. net.