Effect of Ultraviolet Aging on Fundamental Properties of Polymer and Crumb Rubber Modified Asphalt and Asphalt Mixtures

An indoor aging simulation was carried out to investigate the effect of ultraviolet (UV) aging on the performance of polymer and crumb rubber modified asphalt (PRMA) and its mixtures. At the macro level, the apparent morphology change in the asphalt after UV aging and the changing rates of penetration, ductility, and softening point were analyzed to evaluate the effect of UV aging on the asphalt binder. Fatigue life, dynamic stability, freeze-thaw splitting strength, and failure strain were used to determine the effect of UV aging on the asphalt mixtures. At the micro level, using the large molecular weight and functional group index of asphalt after aging as the evaluation index, the effect of UV aging on the performance of asphalt and asphalt mixtures was quantitatively analyzed. The results for the asphalt binders and mixtures under the same UV aging condition showed that PRMA surface cracking appeared later and crack development was slower; the changing rates of the three indexes of PRMA and the performance reductions, including low- and high-temperature properties and moisture resistance, were smaller. The results also showed that the large molecular weight of the two asphalt binders increased gradually, but the increase in large molecular weight of PRMA appeared later and the range was smaller. Also, the changing rules of the three characteristic functional groups of the two binders were basically the same, and the incorporation of rubber powder delayed UV aging of PRMA to a certain extent.