Assessment of Virgin Binder-Blended Rejuvenators and Antistripping Agents for Hot Recycled Asphalt Mixture

Abstract

Effect of rejuvenators and antistripping agents on the aging and moisture resistance of asphalt binders and recycled asphalt mixes is presented in this paper. One base binder (VG 30), one rejuvenator (R), two antistripping agents (A1 and A2), one antistripping agent-cum-rejuvenator (A–R), and one aggregate gradation (Dense Bituminous Macadam) were used during the laboratory investigation. Hot mix asphalt (HMA) samples were prepared using 30% recycled asphalt pavement material (RAPM). From the active and passive adhesion tests, it was found that the use of A–R improved the workability (with a mixing time of 49 s) as well as bonding at the asphalt aggregate interface (97.5% bitumen coverage). The stiffness (in terms of zero shear viscosity and performance grade) was reduced using rejuvenators, while the antistripping agents had no significant effect on the properties of the base asphalt binder. Aging and moisture conditioning led to the increase in true PG temperature by 2–16%. Results from tests conducted on HMA did not correlate well with the conclusions drawn from binder test results. Antistripping agents improved the moisture resistance of recycled HMA, while no specific trend between the additives could be observed. The retained Marshall stability (RMS) values of asphalt mixes prepared using A1, A2, and A–R were found to be more than 100% after long-term aging (LTA) condition. Post LTA, when the rejuvenator gets sufficient time to interact with the RAP binder, improvement in mixture properties were observed. Overall, A–R gave the most desirable results, anticipating field conditions. © 2022, The Author(s), under exclusive licence to Chinese Society of Pavement Engineering.