Damage and fracture characterization of asphalt concrete mixtures using the equivalent micro-crack stress approach

2017 Elsevier Ltd In this paper, a new parameter termed equivalent micro-crack stress (mc) is proposed for the evaluation of the cracking performance of asphalt mixtures with respect to their resistance to the initiation of micro-crack. The equivalent micro-crack stress (mc) is a function of the material stiffness and the micro-crack initiation threshold (MCIT). The MCIT is a critical strain energy density at the instance of initiation of micro-crack. Experimental testing is carried out for the evaluation of the cracking performance of unmodified and wax modified asphalt mixtures using the Superpave IDT tests at 20C, 10C and 0C. The low temperature range is used in the study to minimize the effect of viscoplastic dissipation on the material cracking behaviour. The result shows that the equivalent micro-crack stress (mc) gives a good indication of the material cracking performance of the unmodified and wax modified mixtures. A Finite Element Analysis is performed to assess the validity of the proposed approach under cyclic loading condition in the controlled-stress mode. The result shows that there is a good agreement between the material cracking performance in both monotonic and cyclic loading conditions using the proposed approach. The higher the effective micro-crack stress (mc), the better the fracture performance of the mixture.

Damage and fracture characterization of asphalt concrete mixtures using the equivalent micro-crack stress approach Academic Article