Energy-based damage and fracture framework for viscoelastic asphalt concrete

• An energy-based model for damage and fracture in viscoelastic asphalt mixtures.
• Based on continuum damage mechanics and thermodynamics of irreversible processes.
• Energy-based criteria are introduced for micro-crack initiation and accumulation.
• A temperature-dependent critical micro-crack threshold is established.
• Model describes damage for both conventional and non-conventional asphalt mixtures.

A framework based on the continuum damage mechanics and thermodynamics of irreversible processes using internal state variables is used to characterize the distributed damage in viscoelastic asphalt materials in the form of micro-crack initiation and accumulation. At low temperatures and high deformation rates, micro-cracking is considered as the source of nonlinearity and thus the cause of deviation from linear viscoelastic response. Using a non-associated damage evolution law, the proposed model shows the ability to describe the temperature-dependent processes of micro-crack initiation, evolution and macro-crack formation with good comparison to the material response in the Superpave indirect tensile (IDT) strength test.