Effect of dry–wet cycle aging on physical properties and chemical composition of SBS-modified asphalt binder

Abstract

In this paper, dry–wet cycle aging method was applied to simulate the aging process in the presence of water. The SBS-modified asphalt binder (SBSMA) with different contents of SBS modifier was used for thermal oxygen aging (TOA) and dry–wet cycle aging (DWCA) for 30 days. The results show that the aging time, water and the dosage of SBS modifier had a significant impact on the physical properties of SBSMA. The results show that the aging time, water and the dosage of SBS modifier had a significant impact on the physical properties of SBSMA. After DWCA for 30 days, the penetration ratio (PR) and softening point ratio (SPR) values of SBSMA were higher than that of base asphalt binder by 26.8–29.2% and 5.3–18.5%, respectively. In contrast to TOA, the ductility retention rate (DRR) values of SBSMA under DWCA were more obvious. When the SBS content exceeded 4.5%, the variation range of SBSMA’s viscosity after DWCA became weaker than that after TOA. The results of Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) show that there were slight drops by 8.9–28.8% and 3.3–13.9% in the contents of carbonyl and sulfoxide functional groups of 4.0–5.0% SBSMA after DWCA compared with those after TOA, due to the scouring effect of water on hydrophilic oxygen-containing functional groups. Moreover, the consumption of butadiene functional groups in SBSMA fluctuated at 20% with the SBS content rose.