Mesomechanical modeling of the thermo-viscoelastic, thermo-viscoplastic, and thermo-viscodamage response of asphalt concrete

Abstract

This paper focuses on the meso-scale computational modeling of the thermo-mechanical response of asphalt concrete mixes using for the first time a compressive coupled thermo-viscoelastic, thermo-viscoplastic, and thermo-viscodamage constitutive model. Asphalt concrete is represented by two-dimensional images of the microstructure that consist of three phases: aggregate, matrix, and interfacial transmission zone (ITZ). The matrix and ITZ are considered as thermo-viscoelastic, thermo-viscoplastic, and thermo-viscodamaged materials, while the aggregate is considered to be elastic. The effects of variation in aggregate shape, distribution, volume fraction, ITZ strength, strain rate, and temperature on the degradation and micro-damage patterns in asphalt concrete are investigated under uniaxial tension, compression, and repeated creep-recovery loading conditions. It is concluded that the aggregate volume fraction and distribution significantly influence the micromechanical response of asphalt concrete. Additionally, the results indicate that the constitutive model presented in this paper can provide a computational tool for predicting the overall macroscopic behavior of asphalt concrete based on the distribution of the microstructure constituents and the properties of these constituents. As such, the results of this computational model can be used to guide the design of asphalt concrete mixtures.