Influence of aging induced by mutation in temperature on property and microstructure development of asphalt binders

Abstract

Aging is a main factor leading to deterioration of asphalt binder performance. However, the traditional aging methods cannot simulate the aging behaviors of asphalt binder under the dynamic thermal process. Therefore, the self-designed mutation temperature aging cycle (MTAC) test was carried out on three different asphalt binders to simulate dynamic thermal aging process in this work. Dynamic shear rheometer (DSR), gel permeation chromatography (GPC) and atomic force microscopy (AFM) were used to test the rheological properties, molecular size evolution and microstructure of the three binders after PAV aging and different number of cycles of MTAC. The results show that the binder gradually becomes hard and brittle with the increase in the number of aging cycles at the mutation temperature; while the modified asphalt binder is relatively better. Secondly, the large molecular size (LMS) of binder increases and the small molecular size (SMS) decreases after aging. The aging degree of PAV is between 20 mutation temperature aging cycles (MTAC20) and 30 mutation temperature aging cycles (MTAC30). In addition, the MTAC process can lead to an increase in the aspect ratio and area of bee structure in the binder. Overall, this work provides some new ideas for the aging behavior of asphalt binders under dynamic thermal changes.