A MECHANISTICALLY AND RISK BASED DESIGN METHOD FOR CONCRETE PAVEMENTS IN SOUTHERN AFRICA

Abstract

The Cement Industry identified the need to develop a design method that would be easy for practitioners to use. The method was to be mechanistically based in order to facilitate interaction with the mechanistic flexible pavement design methods currently in use and to promote the use of concrete to rehabilitate flexible pavements. The paper describes the development of suitable models from finite element and multi- layer evaluations as well as the computer program that was subsequently compiled. The design procedure takes into account voids under the slab, load transfer characteristics through aggregate interlock and dowels, the influence of traffic mix, tyre pressures and speed of loading. Pavement characteristics change with time and the different parameters show statistical variation. All of this, together with actual field performance, was taken into account to generate the output which is expressed in terms of risk of failure. In order to achieve a practical design tool, the performance of different concrete pavement sections (roads, streets and hardstandings), some of which were accurately instrumented, were used to calibrate the method.