Physical and rheological properties of nano zinc oxide modified asphalt binder

The main objectives of this work were to investigate the physical and rheological properties of nano zinc oxide (NaZO) flake structure as a modifier in asphalt binder. NaZO was produced with hydrothermal method by using two precursors, which are zinc nitrate and sodium hydroxide. NaZO was mixed with virgin binder 60/70 penetration grade at 3%, 5% and 7% of asphalt binder weight, respectively. The physical properties were evaluated by conventional testing, such as penetration, softening point and viscosity. Meanwhile, the rheological property, such as rutting resistance, was measured by using a dynamic shear rheometer (DSR) for unaged and rolling thin film oven (RTFO) aged. It was observed that the penetration value was decreased and the softening point increased with increasing NaZO concentrations. In addition, the rutting resistance factor was increased for the modified binder. A comparison between the modified binder, 7% NaZO, showed a greater resistance to rutting before and after aging. Results of this study showed that the NaZO addition had increased the asphalt binder stiffness; thus, could contribute to better resistance to permanent deformation.