A density-driven damage mechanics (D3-M) framework for asphalt mixtures under large strain and cyclic loading

This study presents a Density-Driven Damage Mechanics (D3-M) model for asphalt mixtures that combines large-strain kinematics, thermodynamic consistency, and hyperelastic theory to characterize cyclic fatigue behavior. A temperature- and frequency-dependent reference configuration, derived through a modified correspondence principle, is used to compute reference strain from Prony-series viscoelastic properties. Stress is expressed in terms of stretch ratios and a scalar modulus that evolves with internal damage. Damage evolution is governed by a density degradation function linking modulus and stress reduction to the ratio of current to reference mass density. The framework was implemented in two stages: calibration using mixtures grouped by binder grade and validation using independent mixtures with averaged parameters. Incompressible and quasi-incompressible formulations were evaluated; the quasi-incompressible form with Poisson’s ratio of 0.3 better reproduced measured stress responses by accounting for volumetric effects. Validation used 43 datasets from 15 asphalt mixtures tested at 15–25 °C, 5–10 Hz, and 250 με. The model accurately predicted stress evolution and fatigue life, defined at 50% stress reduction, without refitting validation-mixture parameters.