Investigation and optimization of short-term aging test conditions for asphalt binders

Abstract

The existing short-term aging test methods have disadvantages such as not being suitable for high viscosity modified asphalt, different aging degrees between them and poor testing convenience. Therefore, this paper investigated and optimized the aging test conditions of asphalt. The macroscopic rheology and microchemistry of aged asphalt prepared by different aging conditions were comprehensively evaluated. Finally, the most suitable aging test conditions for asphalt was determined by referring to the aging degree of loose asphalt mixture. The experiment results showed that after aging, the rutting factor, carbonyl index, asphaltene content, and creep stiffness of asphalt would increase. The aging degree of existing asphalt aging methods (TFOT and RTFOT) and the corresponding loose asphalt mixture was quite different, and the difference percentage could reach 86.6%. Based on the TFOT test, the asphalt aging conditions were optimized. The aging temperature was 163 ℃. For 70# and SBS modified asphalt, the recommended asphalt film thickness and aging time were 1.59 mm–85 min and 0.80 mm–85 min, respectively. The aging degree of high viscosity modified asphalt under the condition of 0.80 mm–85 min was close to the aging degree of loose asphalt mixture at 135 ℃, and the aging degree of 0.80 mm–100 min was close to the aging degree of loose asphalt mixture at 165 ℃. The proposed aging test conditions can not only accurately simulate the short-term aging behavior of asphalt, but also shorten aging time and save resources.