Combined Effect ofWheel and Thermal Load Conditions on Stress Distribution in Flexible Pavement

Abstract

The aim of this research is to study the behavior of flexible pavement underwheel and thermal loading conditions using the finite element program ANSYS V(5.4). The stress states distribution within the asphalt concrete pavement thatinfluence the direction of crack propagation have been investigated. The obtainedresults from ANSYS finite element program show that a maximum stress intensityfactor value obtained at surface and then decrease with depth about (0.75 ofasphalt layer thickness) due to reduction in temperature in asphalt layer, whichindicates that crack will initiate at surface and extend throughout asphalt layer.The horizontal stress for both top and bottom layers increase with the variation ofthermal coefficient expansion factor. High values of stresses at top surface ofasphalt layer due to high contact stress were induced under wheel and thermalload conditions. As a result the highway pavement exhibited propagation ofsurface –initiated cracks. Field observation of cores extracted from asphaltconcrete pavement confirmed the obtained results.