Ultraviolet irradiation of crumb rubber on mechanical performance and mechanism of rubberised asphalt

Nowadays, researchers have studied influences of ultraviolet on crumb rubber (CR)-modified asphalt (AR) and attempted to comprehensively understand mechanisms of ultraviolet on asphalt or AR entirety. In this article, ultraviolet influences on CR are discussed: mechanical performances of matrix asphalt, AR and strong ultraviolet-irradiated CR-modified asphalt are evaluated by dynamic mechanical analysis, bending beam rheometer and dynamic shearing rheometer (DSR); mechanisms of ultraviolet on CR, irradiated CR on asphalt and morphologies of CR are analysed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Results implied: (i) CR barely reacts with asphalt but irradiated CR reacts vigorously with asphalt by its new chemical bonds and growing internal crosslinkings; (ii) CR has a rough surface with porous shape and size but ultraviolet makes it become dense caused by oxidation; (iii) irradiated CR weakens low-temperature performances but enhances high-temperature anti-shearing performances of asphalt.