Influence of Different Aging Environments on Rheological Behavior and Structural Properties of Rubber Asphalt
Research on asphalt aging properties mainly focuses on temperature and ultraviolet (UV) radiation, while water, acid and salt media in natural environment are often ignored. According to the aging simulation of self-made UV environment chamber, the influence of the coupling effect of different media and UV radiation on rubber asphalt properties was analyzed through physical properties, rheological properties and micro characteristics, and the structural properties of asphalt were revealed. The results indicated that different media can accelerate the aging of rubber asphalt. The penetration, creep rate and non-recoverable creep compliance of asphalt decreased, while the softening point, rutting factor, recoverable rate, fatigue factor and stiffness modulus increased. The coupling effect between acid and UV radiation had the most impact on asphalt rutting and fatigue cracking. The rubber asphalt performed better at high-temperature after aging, and it was more prone to fatigue damage and performed worse at low-temperature. Through the oxygen absorption reaction causing asphalt aging, the intensity of the absorption peaks of the carbonyl and sulfoxide groups increased and the light components of the asphalt transitioned to heavy components under UV radiation. These media intensified this process, which resulted in the gradual transformation of the asphalt colloid structure into a gel type. The carbon black contained in the waste rubber powder made the rubber asphalt exhibit better anti-aging properties.