Performance Characterization of Recycled-Asphalt Pavement with Stabilized Rubber–Modified Asphalt Using Balanced Mix Design Method

AbstractThe rejuvenator is typically utilized to partially recover the mechanical properties of reclaimed-asphalt pavement (RAP). Although the rejuvenator works effectively in softening the highly aged recycled asphalt and improving workability, the rutting and cracking performance of recycled materials cannot be well guaranteed. In this paper, the potential of generating an asphalt mixture incorporating RAP with both strong rutting resistance and improved cracking resistance is evaluated. Rubber, rejuvenator, and their combination are utilized, respectively, to modify recycled asphalt from field cores, and their basic rheological properties are evaluated. Both Marshall mix design and balanced mix design methods are conducted to design recycled-asphalt mixtures with proper material properties. The effects of RAP content and asphalt content on the performance of recycled-asphalt mixtures are also quantified. Results show that rubber modification can increase rutting resistance and low-temperature resistance of recycled-asphalt binder. Although the application usage of rejuvenator is able to soften the recycled-asphalt binder and decrease viscosity, whereas the inclusion of rubber particles can further increase the resistance to fatigue and rutting of recycled-asphalt binders. It is also found that both the rubber modification and rejuvenator can improve binder’s ability to resist low-temperature cracks. Additionally, the Marshall and balanced mix design methods indicate that increased RAP content always leads to increased rutting stability and decreased fatigue crack resistance, whereas moisture resistance and low-temperature resistance are not clearly affected. The addition of rejuvenator can also improve the low-temperature performance and fatigue resistance of recycled-asphalt mixtures and lessen the high-temperature performance, whereas it does not change its moisture resistance property.