A VECD model integrating Viscoelasticity and Damage Evolution in Asphalt Concrete

Abstract

Viscoelastic-Continuum Damage (VECD) models are developed for asphalt concrete to describe the damage it undergoes due to repeated loading and the evolution of viscoelastic properties because of the damage. These models consider the material as a continuum and use a damage parameter that evolves based on the deformation history to capture the damage behavior. Traditional VECD models, which utilize Schapery's work potential theory and the elastic-viscoelastic correspondence principle, impose constraints on how viscoelastic properties evolve with damage. This study introduces a new VECD model that couples viscoelasticity and damage characteristics within a Helmholtz-potential-based thermodynamic framework, ensuring thermodynamic consistency and eliminating the constraints prevalent in traditional VECD models. The model captures the sudden decrease in modulus towards the end of the fatigue life of the material. It also allows for the phase angle to evolve without constraint, because of which it can increase, decrease, or remain constant with any increase in fatigue damage.