Summary
This paper reviews present knowledge of the thickness, length and width of concrete road slabs, the use of reinforcement and the functions and design of joints. Consideration is given to the factors causing stresses; while approximate estimates may be made of the stresses caused by wheel loads, temperature gradients and changes in the mean temperature of the slab, it is not possible to calculate the stresses caused by certain other factors. It is therefore necessary to rely on the knowledge gained from experience and experiment when making recommendations. for future designs.
The thicknesses recommended for five different traffic conditions and for three soil divisions are given in Table 1. It is considered that the strength properties of the soil are of less importance than the uniform behaviour of the soil and the avoidance of differential deformations. It is contended that the base only serves a useful purpose on poor soils and to resist the effects of frost.
The spacing recommended for joints is a compromise between the desire to reduce the number of joints as much as possible and the need for providing some facility for the slabs to expand and contract. The recommended spacings are given in Table 2.
It is now accepted that reinforcement is necessary if the effect of cracking is to be minimized or eliminated. Consideration is given to the position and the amount of the reinforcement, and the recommended quantities for different soil and traffic conditions are enumerated in Table 3.
The functions of the various types of transverse joint used in concrete road construction are discussed and details are given in Figures 4—8 of suitable designs for transverse and longitudinal joints.
