Micromechanics-Based Relaxation Property Analysis of Crumb Rubber Modified Asphalt Concrete

Relaxation property of crumb rubber modified asphalt concrete (CRMAC) has a significant impact on the pavement performance at low temperatures. Although laboratory tests attempt to investigate the relaxation property of CRMAC, a predictive model founded on the microstructure of CRMAC is more desirable for saving limited natural and economic resources. A micromechanical model is presented to analyze the relaxation property of CRMAC that is considered to be a composite of asphalt concrete as the matrix and crumb rubber as the inclusion. The model of CRMAC is established based on effective modulus theory of the composite and incorporates viscoelasticitiy of asphalt concrete and crumb rubber developed to predict the effective relaxation modulus of CRMAC. This paper will explore the reasons behind the discrepancy that occurs between the prediction and laboratory test results. The further studies on mechanical properties of crumb rubber and microstructure behavior of CRMAC are indispensable to obtain the rigorous micromechanical model in future research.