Analysis of Top-Down Cracking of Asphalt Pavements Using Fracture Mechanics Approach

Abstract:

In this study, the effects of temperature, vehicle speed, crack length and base type on the stress intensity factor (SIF) at the tip of top-down cracking in asphalt pavements under moving load were evaluated by conducting fracture mechanics and finite element (FE) analyses. Dynamic modulus master curves and time-temperature shift factors were incorporated into the FE model to characterize the mechanical properties of asphalt mixtures. The results show the peaks of tensile type SIF (KI) and shear type SIF (KII) increase as crack length increases and temperature decreases. Vehicle speed has significant influences on the frequency of SIF and slow traffic loading can accelerate the propagation of top-down cracking. The use of semi-rigid bases in asphalt pavements can reduce SIF compared to granular bases. The contribution of KI to the propagation of top-down cracking becomes less significant, while that of KII becomes more evident when temperature and crack length increase.