Conférence : 4th International Congress on Material & Structural Stability, 7 March 2023
Asphalt mixtures also referred to as asphalt concrete (AC), which is one of the widely used materials in the pavement engineering is a complex and multiscale particulate composite material. AC is a viscoelastic composite that comprises aggregates, bituminous matrix, and air voids. When testing asphalt mixtures under mechanical cyclic loading, part of the energy brought by the loading is dissipated due to the viscous effects of the bituminous matrix and translated into a heat source causing the temperature increase (self-heating). The released energy represents the source of the damage growth. This work deals with a new thermodynamic approach to describe rheological models applied to viscoelastic materials subjected to mechanical cyclic loading. This approach is based on a description of the 1st and the 2nd thermodynamic principles, which allow separating the energy release rate and the dissipation rate. An electromechanical analogy is used to generalize this approach to all viscoelastic rheological models. Both thermal and mechanical aspects and their coupling are taken into account leading to complete constitutive modeling to simulate the decrease of the AC complex modulus. Based on an image processing approach, a heterogeneous microstructure is used to model the AC. Therefore, the simulations are performed on a regular mesh based on heterogeneous thermomechanical property fields.