Improvement of aggregate interlock equation for new mechanistic concrete pavement design method

This paper presents aspects of an investigation into methods for modelling aggregate interlock shear transfer in jointed concrete pavements. The aim was to improve the aggregate interlock load transfer equation used in the software developed for the new South African mechanistic concrete pavement design method. The paper presents the evaluation of the results of the investigation into aggregate interlock load transfer efficiency across joints in concrete slabs subjected to simulated 20 kN dynamic wheel loads and 40 kN control laods. One of the main conclusions reached from the study was that there was no significant deterioration of the crack face during dynamic loading, which indicated that fatigue of the aggregate interlock at the joint face did not play a role. This could be attributed to the high quality of the crushed stone used in South Africa. The equation developed from the laboratory results was used to refine the aggregate interlock load transfer model in the software developed for the new mechanistic design method.