Influence of Aging on Healing of Asphalt Binder

This study investigates the effect of aging on the healing behavior of asphalt binder. Asphalt binders were subjected to the different types of aging in a laboratory to simulate the field aging. In this study, Rolling Thin-Film Oven, Pressure Aging Vessel (PAV), and double PAV were used to condition the binder in the laboratory. Fourier Transform Infrared Spectroscopy analysis was used to identify the change in the functional groups of the asphalt binder that is due to aging. Dynamic Shear Rheometer was used for the healing (fatigue with rest period) test at different rest periods. Also, the tack test was used to evaluate the change in the cohesion of the binder that was due to aging. Finally, the healing test data were fitted to a physicochemical healing model developed by Wool and O’Connor. This model divides the overall binder healing into two parts: instant healing and long-term healing. Results show that the overall healing decreases because of aging, and the long-term healing rate is inversely proportional to the sulfoxide groups in the aged binder. Aging causes a reduction in both the instant and the long-term healing by reducing the molecular mobility and the long-chained molecular structure of the asphalt binders. In summary, the healing of asphalt binder deteriorates when the binder is aged.