Aging Potential and its Impact on the Bonding Strength of Rubberized RAP Asphalt Binder
Ahmed S. Mohamed, Sherif M. El-Badawy, Feipeng Xiao
Abstract
Rejuvenating the reclaimed asphalt binder using crumb rubber-modified binder is a sustainable paving technology that has the advantage of using waste to recycle another waste material. As binder durability is crucial in evaluating the recyclability of reclaimed asphalt using crumb rubber-modified binder, this study investigates the binder potential for aging and the impact of aging on binder bond strength. Thirty binders with different crumb rubber and reclaimed asphalt dosages were aged by rolling thin oven and pressure aging vessel and tested by Fourier-transformed infrared spectroscopy and pull-off tests. The results reveal that binder aging and reclaimed binder addition strengthen the bonding strength and elevate the carbonyl intensity, which is the keen factor responsible for bonding enhancement. However, incorporating reclaimed binders attenuates the binder aging potential and limits the bonding enhancement after aging. Crumb rubber interacts with the asphalt binder and improves the bonding strength accordingly. However, the crumb rubber interaction with the binder significantly affects the aging potential of the binder, which increases with crumb rubber disintegration and decreases with rubber swelling. As rubber swelling is the dominating interaction mechanism, the crumb rubber modification mostly undermines the bonding enhancement after aging.