Study on the effect of aging on cracking resistance of virgin asphalt binder and its evolution model

The cracking resistance of asphalt pavement is significantly affected by the aging of asphalt binder. A better understanding of the effect of aging on the cracking resistance of virgin asphalt binders can help to determine the optimum maintenance time. In this study, the rolling thin film oven test (RTFOT) and pressure aging vessel (PAV) test were conducted to simulate short-term aging and long-term aging of asphalt binders, respectively. Frequency sweep tests were conducted on two asphalt binders at different aging conditions. The Glover-Rowe (G-R) parameter, stiffness modulus (S), creep rate (m), continuous grading temperature (T_c), critical temperature difference (ΔT_c), relaxation time (λ), dissipation energy ratio (W_d/W_s), low-temperature indicator ratio (m/S), low-temperature comprehensive compliance parameter (J_c) were obtained. Meanwhile, the sensitivities of different indicators to aging were analyzed and the correlations between G-R parameter and various low-temperature indicators were discussed. Subsequently, a nonlinear model of asphalt binder aging was established by a rheological indicator. The results showed that aging had a significant impact on the low-temperature properties of asphalt binder. G-R parameter, T_c, λ increased with the growth of aging severity, whereas m, ΔT_c, W_d/W_s were contrary to this trend. S, m/S, J_c had no significant relationship with the degree of aging. Moreover, G-R parameter and ΔT_c were very sensitive to aging. The G-R parameter had a good correlation with m, T_c, λ, ΔT_c and W_d/W_s, respectively. It indicated that G-R parameter was closely related to the low-temperature properties of asphalt binders. The aging nonlinear model containing G-R parameter could exactly describe the aging evolution of virgin asphalt binder. It is helpful for the prediction of cracking resistance of asphalt binder and determination of maintenance plan.