An Investigation of the Effect of the Chemical Properties on the Rheological Properties of Asphalt Binders

The asphalt binder, a hydrocarbon material, is crucial in controlling the rutting and fatigue performance of the flexible pavement. The difference in the chemical structure of asphalt binder can make a remarkable change in its performance. In view of this, the present study aims to investigate the effect of the chemical composition of asphalt binder on the rutting and fatigue performance. Five different asphalt binders including polymer-modified, crumb rubber-modified, Sasobit-modified, and unmodified binders were considered in this study. The rutting and fatigue behaviors were evaluated using a dynamic shear rheometer (DSR). Furthermore, Iatroscan thin layer chromatography-flame ionization detection (TLC-FID) and Fourier transform infrared (FTIR) spectroscopy were used to determine the chemical composition of the binders. In this investigation, polymer-modified binder (PB) outperformed all other binders, followed by crumb rubber-modified binder (CRB), Sasobit-modified binder (SB), viscosity grade 40 (V4), and viscosity grade 30 (V3). Higher rutting and fatigue resistance of modified binders were observed in compliance with the high carbonyl index (ICO), sulfoxide index (ISO), aromaticity index (ICC), and low aliphatic index (ICH). A positive correlation was found between the asphaltenes of binders and rutting and fatigue parameters. The overall good correlations between failure phenomena (rutting and fatigue) and chemical composition emphasized that the chemical structure of the binder plays an important role in pavement performance. Depending on the application and environmental circumstances, these patterns demonstrate the impact of modifications, such as adding polymers or rubber, on the binder's behavior to maximize rutting resistance and fatigue performance.