Long-Term Performance of Oil Recycled Asphalt Binders Based on Fatigue, Moisture Damage, and Oxidation Aging

The main objective of this work is to characterize the long-term performance of corn oil and refined engine oil bottom (REOB) recycled asphalt containing reclaimed asphalt pavement (RAP) binders, from the perspectives of fatigue, the bonding strength between asphalt and stone, and oxidation aging, as well as evaluating how long the rejuvenating effectiveness of these oils could remain. Two corn oils and one REOB were utilized as the recycling agents to recover the performance grade (PG) of asphalt containing RAP binders, where the content of RAP binder in asphalt has two levels, i.e., 27% and 45%. The oils and recycled asphalt binders were subjected to rolling thin-film oven (RTFO) and pressure aging vessel (PAV) aging. The aging property of three recycling agents was characterized based on the change in apparent viscosity throughout the aging process. Furthermore, the long-term performance of recycled asphalt binders with RAP binders was evaluated and compared with the base binder based on intermediate-temperature fatigue, resistance to moisture damage, and oxidation aging using the linear amplitude sweep (LAS), bitumen bond strength (BBS) at equal modulus, and Fourier transform infrared (FTIR) tests. The results showed that corn oil and REOB exhibited extremely different aging properties, with the viscosity of corn oils increasing more than 100 times, but that of REOB remained stable. Results of asphalt binders indicated that asphalt binders recycled by corn oils exhibited some advantages regarding fatigue performance. Corn oils and REOB hardly work in terms of improving antimoisture damage, whereas oxidation aging of recycled asphalt binders is governed by both the RAP binder (slowing down oxidation aging) and oils (accelerating oxidation aging).