Multi-scale Evaluation of Rutting Resistance in Reclaimed Asphalt Pavement Mixtures through Linking Binder Rheology with the Hamburg Wheel-Tracking and the IDEAL Rutting Tests

This study proposed a multi-scale framework for evaluating rutting resistance in recycled asphalt mixtures by linking binder rheology with mixture-scale performance. One virgin mixture and seven mixtures containing 50% reclaimed asphalt pavement (RAP) were prepared with three rejuvenators at two dosages. Binder properties were characterized using DSR, while rutting performance was evaluated using HWTT and IDEAL-RT. The binder parameter G*/sinδ was interpolated at 50°C to enable comparison with mixture tests at the same temperature. Results showed that the 50% RAP mixture without rejuvenator reduced rutting depth by 41.5% compared with the virgin mixture and exhibited the highest RTIndex. All mixtures had HWTT rutting depths of 3.29–5.82 mm, below the 12.5 mm criterion. RTIndex showed a strong inverse correlation with rutting depth (R² = 0.821), supporting IDEAL-RT as a rapid complementary rutting test.