Effect of Nano-zinc Oxide on the Morphology and Ultraviolet Aging Properties of Various Bitumens

Effect of nano-zinc oxide (nano-ZnO) on the morphology and ultraviolet (UV) aging properties of two bitumens was investigated by atomic force microscopy, physical properties and Fourier transform infrared spectroscopy before and after UV aging. The results show that the mechanism of nano-ZnO depends on the base bitumen. In one case, nano-ZnO contributes to the homogeneous dispersion of bee-like structures. In the other case, it leads to the separation of asphaltenes from the matrix. Compared with B2, nano-ZnO exhibits a better improvement in UV aging resistance of B1 by showing the lower increased viscosity values, rheological aging index, and carbonyl indexes.