A Micromechanical Viscoelasto-Plastic Model for Asphalt Mixture

Abstract

This paper presents a finite element (FE) micromechanical model for viscoelasto-plastic behavior of asphalt mixtures. Asphalt mixture is composed of highly irregular aggregates, mastic (asphalt plus fine aggregate and fines), and air voids. In this paper, the microstructural model of particulate asphalt materials incorporates an equivalent lattice network structure whereby intergranular load transfer is simulated through an effective asphalt mastic zone. The finite element model integrates the ABAQUS user material subroutine with continuum elements for the effective asphalt mastic and rigid body elements for each aggregate. A FE incremental algorithm with a recursive relationship for three-dimensional (3D) viscoelastic behavior was developed. Chaboche's plastic model was applied, and the constitutive equations were solved using a predictor-corrector scheme. These algorithms were defined in a 3D user material model for the asphalt mastic to predict global rate-independent permanent deformation of asphalt materials. The effect of loading rates on the material viscoelastic and viscoelasto-plastic behavior was investigated using FE numerical simulations for an ideal asphalt mixture specimen.