A novel visco-elastic damage model for asphalt concrete and its numerical implementation

The creep of asphalt and asphalt concrete were numerically studied extensively. However, most of the previous studies only researched the decelerated creep stage and equi-velocity creep stage while rarely shed light on the accelerated creep stage. This paper proposes a novel 3 dimensional visco-elastic damage model utilizing two spring and one dashpot components coupled with Kachanov and Robotnov (K-R) creep damage theory to describe the whole stages of the creep of asphalt and asphalt concrete, i.e., decelerated creep stage, equi-velocity creep stage, and accelerated creep stage. The damage evolution equation based on the K-R creep damage theory is integrated into the visco-elastic constitutive model by the continuum mechanics, and then the uniaxial creep damage solution is deducted. A robust numerical algorithm of this model is developed. Through numerical tests on uniaxial compression and pre-notched three-point bending beam, the numerical curves are analogue to measured creep curves, which justifies the accuracy and efficiency of the visco-elastic model coupling with K-R creep damage theory and the corresponding numerical algorithm. This paper provides not only an accurate and robust creep damage constitutive model for the asphalt and asphalt concrete, but also a valuable model and an efficient numerical method to evaluate the damage and rupture behavior of large-scale infrastructures fabricated by asphalt and asphalt concrete.