Impact of rejuvenators on aging properties of bitumen

Potential reductions in construction costs and environmental emissions have made the use of reclaimed asphalt pavement (RAP) as aggregates in hot bituminous mixes an attractive alternative to the highway agencies. Currently, there is a trend towards increasing the RAP content in asphalt pavements and recycle 100% RAP in asphalt mixes. However, RAP binder is already aged and stiffened, making the RAP containing mixes susceptible to fatigue and thermal cracking. Addition of rejuvenators may reduce the viscosity of the 100% RAP binder allowing restore some of the original characteristics of the aged binder in order to attain adequate performance of the mixture. This paper aimed to determine the aging behavior of rejuvenated 100% RAP binder and compare it with that of the virgin bitumen. Three types of rejuvenators were assessed in the study. The rheological tests conducted on the bitumen include softening point, penetration, and complex shear modulus. The tests were performed at 3 aging stages: no-aging, RTFOT (Rolling Thin Film Oven Test) aging, and combined RTFOT and PAV (Pressure Aging Vessel) aging. Aging of the bitumen was characterized using Fourier Transformed Infrared Spectroscopy (FTIR). It was shown that the aging of the virgin bitumen is slower than that of the rejuvenated bitumen. However, there was no significant difference between the aging behavior of the bitumen mixed with different types of rejuvenators.