THE STUDY ON TOP-DOWN CRACK PROPAGATION IN ASPHALT PAVEMENTS BASED ON THE COUPLED EFG AND FE METHOD

摘要

Top-down crack in asphalt pavements has been reported as a widespread mode of failure.A solid understanding of the mechanisms of crack growth is essential to predict pavement performance in the context of thickness design, as well as in the design and optimization of mixtures.By using the coupled element free Galerkin (EFG) and finite element (FE) method, top-down crack propagation in asphalt pavement is numerically simulated based on the fracture mechanics. With the analysis of the following three indicators, the stress intensity factor (SIF) which varies as the crack propagating, the crack path and the fagitue life, the mechanism of top-down crack is discussed.Furthermore, a parametric study is conducted to isolate the effects of various parameter on top-down crack propagation. The results show that the SIF experiences a process "sharply ascending- slowly descending- slowly ascending- sharply ascending again" as the crack propagating; the thicker overlay or base is, the lower the SIF becomes; the greater overlay stiffness is, the higher the SIF should be;the crack path is obviously affected by the stiffness of overlay and base; the greater the stiffness is,the longer the crack path gets.