Laboratory investigation on low-temperature performance of asphalt at different aging stages

This paper seeks to introduce an Improved Simple Aging Test (ISAT) as a new method for short-term and long-term aging of asphalt binder. Two kinds of asphalt, SK and ZH, were selected to be aged in the laboratory with the ISAT. The properties of the aged asphalt were investigated, including the high-temperature viscoelastic behavior, low-temperature performance and chemical composition. Moreover, the high-temperature viscoelastic behavior of the aged asphalt with different aging methods (LAST, Rotated thin Film Oven Test (RTFOT), and Pressurized Aging Vessel (PAV)) were also examined. The results show that aged asphalt in ISAT for 120 min at 163 degrees C have a similar viscoelastic behavior compared with the RTFOT, meanwhile the same conclusion between LSAT for 72 h at 95 degrees C and PAV can be drawn. By increasing the aging time, the low-temperature performance of the asphalt becomes worsen. At the beginning of the aging process, the performance reduces at a fast nonlinear rate, later the rate becomes constant. When compared with the asphalt SK, the asphalt ZH has a superior low-temperature performance and an inferior reduced rate in its performance at different aging stages. According to the chemical composition analysis of asphalts, the results described above can be well explained from the mechanism. (C) 2019 Elsevier Ltd. All rights reserved.