Prediction of top-down crack resistance in semi-flexible pavements under coupling effect of rutted surface and temperature gradient

Abstract

ABSTRACT Top-down cracking (TDC) as a severe type of cracking has been widely reported in pavements with heavy traffic loads and mixtures sensitive to rutting damages. Since the likelihood of TDC increases as a result of weak mastic, semi-flexible pavements (SFPs) grouted with cement asphalt emulsion pastes (CAEPs) were introduced in this study to evaluate its performance in prevalence or mitigation of this problem. Using laboratory tests, the material properties and rutting resistance of SFP with CAEPs were compared to the conventional asphalt mixture. Then comprehensive finite element (FE) models were employed to investigate the influence of rutting damage severity on non-uniform contact stresses and critical TDC responses. Considering various degrees of rutted surface, the critical locations of TDC were predicted based on maximum transverse and shear strain responses. The results demonstrated that the presence of a rutted surface induced the near-surface responses significantly, and the more severe rutting, the higher propensity for TDC. Besides, the location of TDC initiation was greatly influenced by the severity of the rutted surface. Finally, based on SFP performance in the surface layer, CAEP40 was recommended as the best grouting material to reduce the likelihood of TDC and rutting damage development.