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 to evaluate the rutting resistance of recycled asphalt mixtures by integrating binder-scale rheology with mixture-scale rutting performance. One virgin mixture and seven recycled mixtures containing 50% reclaimed asphalt pavement (RAP) were prepared using three rejuvenators at two dosages. Binder behavior was characterized using the dynamic shear rheometer (DSR), while mixture rutting performance was evaluated using the Hamburg wheel-tracking test (HWTT) and IDEAL rutting test (IDEAL-RT). The rutting parameter G * /sinδ at 50 °C was obtained by logarithmic interpolation to allow comparison with mixture tests conducted 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 RT Index among all mixtures. The HWTT rutting depths of all mixtures ranged from 3.29 to 5.82 mm, remaining below the 12.5 mm criterion. Increasing the rejuvenator dosage from 4% to 12% reduced binder stiffness and RT Index , indicating a stronger softening effect, but all rejuvenated mixtures still maintained acceptable rutting resistance. A strong inverse correlation was observed between RT Index and HWTT rutting depth, with R 2 = 0.821. These findings indicate that IDEAL-RT can serve as a rapid complementary test for rutting evaluation and that integrating DSR, HWTT, and IDEAL-RT provides a more mechanistic basis for performance-based design of rejuvenated RAP mixtures.