Evaluation of the properties of high-content degraded crumb rubber-modified asphalt under thermal oxidation and weathering aging.

In this study, the properties of high-content degraded crumb rubber-modified asphalt (HCDRA) under thermal oxidation and weathering aging were analyzed by the fluorescence microscopy test, temperature sweep test, zero shear viscosity test, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) test, and gel permeation chromatography (GPC) test. Morphological structure result shows that after various degrees of thermal oxidation and weathering aging, the number and size of crumb rubber (CR) particles in HCDRA became smaller. Besides, with the deepening of the degree of oxidization, the rutting resistance of HCDRA decreases firstly and then increases. The improvement of the anti-aging and temperature sensitivity of HCDRA is better than that of neat asphalt and 20 % content CR-modified asphalt. Moreover, thermal oxidation and weathering aging make HCDRA more sensitive to temperature, and the temperature sensitivity of HCDRA is more affected by long-term aging relative to neat asphalt and 20 % content CR-modified asphalt. ATR-FTIR test and GPC test show that the complex modulus of HCDRA increases with the increase of carbonyl groups after aging, and HCDRA becomes soft and then hard during the aging process with the increase of macromolecule polymer content. Lastly, cluster analysis and principal component analysis reveal that the degree of asphalt oxidation has a strong influence on failure temperature and zero shear viscosity, and small molecule polymer has a significant effect on the temperature sensitivity of rheological properties.