Reversibility of Macroperformance of Virgin Asphalt Binder at Various Aging-Regeneration Stages Based on Rheology

Abstract

In order to effectively evaluate the regeneration effects of different rejuvenators on aged asphalt binder, this study carried out a series of tests and evaluations on the macroperformance of virgin asphalt binder at various aging-regeneration stages. A commercial rejuvenator, aromatic oil, and warm mix agent were selected as rejuvenators. Fifteen asphalt binder samples involved various aging methods, including water-ultraviolet aging, water-free ultraviolet aging, rolling thin film oven test (RTFOT), and accelerated aging by pressurized aging vessel (PAV). High-temperature properties of asphalt binders were evaluated by softening point, and low-temperature properties of asphalt binders were evaluated by stiffness modulus and m-value. The viscoelastic properties were evaluated by complex modulus G*. Test results show that the regeneration effects of different rejuvenators were reflected in the reduction of softening point, stiffness modulus, and complex modulus. Based on performance changes of asphalt binder before and after aging, the reversibility indexes Rsp, RG*, RS, and Rm for quantitative evaluation of macroperformance of rejuvenated asphalt binders were proposed. Through linear fitting, it was found that R2 between the reversibility index Rsp and the reversibility index RG* reached 0.7574, and R2 between RS and Rm reached 0.8683. This provided the possibility of mutual transformation between those reversibility indexes. Last, the macroreversibility index of virgin asphalt binder (ARIV) was proposed. The softening point and stiffness modulus were taken as representative indexes to comprehensively evaluate the recovery of high-temperature, low-temperature, and viscoelastic properties of aged asphalt binder by different rejuvenators. This study provided a unified indicator to quantitatively evaluate the regeneration effect of rejuvenator on virgin asphalt binder. It is helpful for better understanding the aging-regeneration process of virgin asphalt binder and determining the optimum regeneration time and rejuvenator.