Study Of Cracking Characteristic Of Asphalt Mixture Based On Extend Finite Element Method

Asphalt mixture is a quasi-brittle meterial that exhibits time and temperature despendent fracture behavior. Softening of the matirial can be associatted to interlocking and sliding between aggregate, while the asphalt mastic display cohesion and viscoelastic properties. To properly account for both progressive softening and vicoelastic effects occurring in a relatively large fracture process zone(FPZ), a improved cohesive zone modelis employed. The viscoelastic parameters of asphalt mixture are calculated by main curve of relaxed modulus, which could obtained by creep test. The methods of detemine of fracture energy were introduced, which were analyzed in different tempratures by single-edge notched beam (SEB). This paper applies extend finite element (XFEM) and cohesive zone model (CZM) to simulate the crack propagation of disk-shaped compact tension of asphalt mixture. Effecting of the bulk properties (e.g. relaxtion modulus) and fracture parameters (e.g. cohesive fracture engergy) had been analyzed. Numerical results and Wagoner test results were compared to prove that the improved CZM were appropriateness to simulate crack progagation. It also showed that the extend finite element overcomede the shortcomings in crack siumulation, to avoid the tedious pretreatment in crack initiation using conventional finite element, to show the unique adavantages of the extend finite element method considered separately the elastic and viscoelastic of the bulk matirial, it was found that the numerical results were in good agreement with the experiment with the experimental, and at -10℃, the effect of the viscoelastic of asphalt mixture is very small. Simulating of the mixed-mode SEB predicted crack propagation path, which were agreed with experiment.