Effect of Different Inorganic Nanoparticles on Physical and Ultraviolet Aging Properties of Bitumen

The research reported in this paper evaluates a novel bitumen modification through the use of different inorganic nanoparticles, such as nanozinc oxide, nanosilica, and nanotitanium dioxide. In order to improve the dispersion of inorganic nanoparticles in bitumen, inorganic nanoparticles were surface-modified by 3-aminopropyltriethoxysilane. The effect of surface modified inorganic nanoparticles on physical and ultraviolet (UV) aging properties of bitumen was investigated. The UV aging mechanism of the inorganic-nanoparticle-modified bitumen was characterized by using Fourier-transform infrared spectroscopy (FTIR). The results show that 3-aminopropyltriethoxysilane is successfully bound on the surface of the three inorganic nanoparticles in the form of a covalent bond according to the FTIR result. Surface-modified inorganic nanoparticles show good compatibility with bitumen on the basis of high-temperature storage stability. Compared with nanosilica and nanotitanium dioxide, nanozinc oxide shows better dispersion in bitumen. The physical properties of bitumen are slightly influenced by the addition of inorganic nanoparticles. In addition, the changes of physical properties of bitumen depend on the nature of inorganic nanoparticles. The UV aging of bitumen is a process that causes bitumen to harden as indicated by FTIR, penetration, viscosity, and softening point values. However, the viscosity aging index and softening point increment of bitumen can be effectively reduced with the introduction of inorganic nanoparticles, indicating good UV aging resistance of inorganic-nanoparticle-modified bitumen. Three inorganic nanoparticles show different influence on the UV aging resistance of bitumen. Compared with nanosilica and nanotitanium dioxide, nanozinc oxide shows the better improvement in UV aging resistance of bitumen by displaying lower viscosity aging index and softening point increment values as well as the carbonyl index.