Development of a rheology-based mixture aging model for asphalt material cracking performance evaluation

Aging has a significant effect on the performance of asphalt material. Reliable modelling of the change of asphalt mixture properties over time is crucial to evaluating and predicting the performance of the designed pavement. The objective of this study is to develop an aging model to accurately predict the cracking performance of asphalt mixtures over the pavement service life, as well as evaluate the aging susceptibility of mixtures over time. In this study, nine loose mixtures were conditioned in an oven at 95 degrees C for multiple durations to simulate different field aging times. The climatic aging index (CAI) developed by the National Cooperative Highway Research Program (NCHRP) 09-54 project was utilized to calculate the appropriate field aging durations corresponding to the different laboratory aging conditions. Complex modulus tests (E*) were conducted to measure the rheological properties of the conditioned mixtures and further construct the dynamic modulus and phase angle mastercurves. The mixture Glover-Rowe (G-R-m) parameter, incorporating both stiffness and relaxation capacity, was selected and used as the Aging Index Property to model the changes in mixture cracking properties with aging. The results of this study indicate that the developed mixture aging model can effectively capture the two aging reaction periods (fast and constant) of asphalt materials. The developed model can not only be used to evaluate the change of cracking properties over pavement service life, but also detect the aging susceptibility of asphalt mixtures.