Influence of microstructure evolution of bitumen on its micromechanical property by finite element simulation

The microstructure variation plays an essential role in the micro-mechanical performance of the bitumen and the macro-mechanical behavior of asphalt mixtures. This research aims to reveal the influence of the microstructure changes of bitumen on its micromechanical responses. Based on atomic force microscopy (AFM) technology, the microstructure (bee structure: bee, peri, and interstitial phases) of the bitumen was detected. With the self-developed microstructural finite element (FE) models, the micromechanical responses of bitumen with different bee structures were comprehensively simulated. The results show that the computational load-bearing capacity of the bitumen increases with an increase of the peri phase content, but the difference is not significant. The development of high stresses within the bee phase is mainly due to the inhomogeneity of the material. Additionally, the distribution of the tensile strain becomes more homogeneous with the increase of the peri phase content. This research contributes to establishing a better understanding of the relationship between the microstructure of the bitumen and its micromechanical properties.