Study on the correlation between spatial variability of asphalt mixture material parameters and fracture performance

Asphalt mixtures are multiphase heterogeneous composites, the random distribution of the components leads to variability in the internal mechanical parameters of the material, but this variability has a certain degree of spatial correlation. In this study, the spatial variability and correlation of mechanical parameters of asphalt mixture materials are studied. Firstly, the viscoelastic and fracture parameters of asphalt mixtures were obtained by uniaxial compression test and semicircular bending (SCB) test. Then, the covariance decomposition method and Latin hypercubic sampling method were used to build the parameter random fields of long-term equilibrium modulus, flexural tensile strength and fracture energy of asphalt mixtures. Finally, using the extended finite element method to simulate the SCB test in ABAQUS. The results show that the application of the random field technique and the consideration of the spatial variability correlation of asphalt mixture material parameters can well simulate the randomness of the mechanical response of asphalt mixture materials caused by the randomness of the internal mechanical parameters in the laboratory test. The spatial variability of different parameters has different effects on the fracture response of semicircular specimens: the long-term equilibrium modulus and flexural and tensile strength mainly affect the loading stage of the load-displacement curve, while the fracture energy has a greater effect on the unloading stage.