Aging Resistance Evaluation of Asphalt Modified by BRA/NA/AA Composite Modified Asphalt Based on the Rheological and Microscopic Analysis

In this study, Buton rock asphalt (BRA), nano-aerogel (NA), and an antiaging agent (AA) were selected to modify base asphalt to improve its aging resistance. Based on the preliminary performance test results, the optimum dosage of the three modifiers was determined. The asphalt's rheological properties and microscopic properties were tested under different aging methods. Its high- and low-temperature rheological properties were characterized by dynamic shear rheological tests and bending beam rheological tests. Fourier transform infrared spectroscopy (FTIR) analyzed changes in the asphalt's functional groups before and after aging. The ultraviolet absorption capacity of the asphalt before and after aging was studied by an ultraviolet-visible spectrophotometer (UV-VIS). The results showed that the optimal dosing of the modifiers was 2% NA, 10% BRA, 0.3% antioxidant 1010, and 0.4% UV-327. Compared with the base asphalt, the composite modified asphalt with BRA, NA, and AA showed improvement in high- and low-temperature performance. The aging index of both the rheological test and the infrared spectroscopy test showed that the composite modified asphalt had the best resistance to aging. Its resistance to UV radiation was higher than that of the base asphalt, and the BRA/NA modified asphalt. Therefore, the addition of BRA and NA effectively improved the asphalt's high- and low-temperature performance. Addition of the antioxidants 1010 and UV-327 effectively improved its aging resistance.