Study on the Short-Term Aging Behavior of Asphalt Based on PCA and LSM Analysis

Abstract

To compare the aging behavior of asphalt before and after short-term aging, the rolling thin-film oven test (RTFOT) was used to conduct short-term aging experiments involving an A-70 matrix asphalt and styrene-butadiene-styrene copolymer (SBS)-modified asphalt in the laboratory, over aging times of 0, 40, 85, 180, 240, and 300 min. Second, traditional physical property tests, dynamic shear rheological (DSR) tests, and bending beam rheological (BBR) tests were carried out for asphalt binders with different aging degrees, and the microstructure was analyzed by Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). Finally, principal component analysis (PCA) was used to evaluate the significance of the aging evaluation indexes of A-70 matrix asphalt and SBS-modified asphalt, the least-squares method (LSM) was used to eliminate the multicollinearity between the independent variables, and a prediction model for asphalt’s short-term aging behavior was developed. The findings suggest that as the degree of aging increases, the penetration, ductility, roughness, and m−value of asphalt gradually decrease, but other aging evaluation indicators increase. The addition of the SBS modifier will effectively prevent asphalt from oxidizing. Based on the PCA results, the carbonyl index, sulfoxide index, and root-mean square roughness Rq had the most significant relations with the short-term aging behavior of asphalt. In addition, the correlation coefficients between the measured values and predicted values of asphalt macroindexes were more than 0.85, which indicates that the established regression model can accurately predict changes in the physical and rheological properties of asphalt during short-term aging.