A phase-field cohesive zone model for fracture simulation of asphalt mixture

The traditional cohesive zone model (CZM) based on interfacial damage mechanics has been widely used in quasi-brittle fracture simulation of asphalt mixture at low temperature. However, the traditional CZM is mesh dependent in the cohesive fracture simulation. This study aims to introduce a phase field method (PFM) to simulate brittle failure of asphalt mixture. The model was implemented in a framework of finite element method (FEM). The uniaxial tensile test was used to simulate the sensitivity of parameters that may affect the results. Furthermore, typical laboratory tests for evaluating the crack resistance of asphalt mixtures, such as the single-edge notched beam (SEB) test and the semi-circular bending (SCB) test, were simulated to validate the suitability of the PFM. Moreover, the numerical results and computational efficiency of the PFM-based cohesive fracture simulation within FAM was also discussed and compared with those based on CZM. The results indicate that the numerical results of the typical failure tests based on PFM are in good agreement with the experimental results at both macro and micro scales. In addition, the numerical results of cohesive fracture simulation within FAM based on PFM and CZM are slightly different. The brittle behavior of the asphalt mixture predicted based on PFM was more pronounced compared to the results predicted by CZM. Moreover, the cohesive fracture simulation based on PFM requires less computational memory and time. In general, this paper successfully introduced a PFM to study the quasi-brittle failure of asphalt mixture.