Rheological Properties of Activated Rubber Asphalt after Short-Term Aging

This paper researched the rheological properties of activated rubber powder–modified asphalt after aging. However, current aging methods only consider the aging of asphalt binder itself, ignoring the effect of asphalt mixture’s performance and morphology. Hence, this paper proposes a new approach by conducting short-term aging of rubber asphalt from a different perspective. By utilizing the rotating flask method, coating activated rubber asphalt, grafting activated rubber asphalt, and rubber asphalt were recovered from short-term aged rubber asphalt mixtures. A temperature scanning test, multistress recovery creep test, and bending beam rheometer test were used in the study. The aging resistance of rubber asphalts was quantified by infrared spectroscopy test, and the microstructure of aged rubber asphalts was analyzed by utilizing a scanning electron microscope. The results showed that the activation could alleviate the negative impact of aging on the properties of rubber asphalt, especially the grafting activation. The activation could enhance the surface energy of rubber powder, allowing it to continuously swell during the aging process, absorb more light components, and reduce the oxidizable components of rubber asphalts. In addition, grafting activation rubber powder could react with the asphalt, and this reaction made the molecular chain of rubber asphalt fully expanded, limiting the flow of rubber asphalt. The area of contact between the rubber asphalt and air was reduced, and the aging degree was further alleviated. A stable structure was developed inside the activated rubber asphalts, enhancing the antiaging ability.