Assessment and mechanism of antioxidant activity of phenols as asphalt antioxidants

The interest in the antioxidant properties of phenolic compounds in asphalt has grown significantly. This study primarily focuses on the comprehensive assessment and elucidation of the antioxidant activity mechanisms of various phenolic compounds as asphalt antioxidants. The suitability of different antioxidant indices for evaluating the effectiveness of phenolic anti-aging agents in base and SBS modified asphalt is assessed by experimental outcomes. Through this analysis, the anti-aging mechanism of phenolic antioxidants in asphalt is unveiled. Phenolic antioxidants were observed to diminish the G* value of aged asphalt, elevate the δ values of aged asphalt binder, augment the non-recoverable creep compliance of aged asphalt binder, decrease the percent recovery of aged asphalt binder, enhance the fatigue performance of aged asphalt binder, and lower the Ic = o and Ic = c of aged asphalt binder. This indicates that phenolic antioxidants improve the aging and fatigue resistance of asphalt binders, with antioxidant activities in the following order: p-Coumaric acid < resveratrol < tea polyphenol. Moreover, incorporating phenolic antioxidants into SBS modified asphalt not only restrains asphalt oxidation but also mitigates SBS degradation.