Influence of surface modification on physical and ultraviolet aging resistance of bitumen containing inorganic nanoparticles

• The compatibility between inorganic nanoparticles and bitumen is improved by surface modification.
• The UV aging resistance of bitumen can be effectively improved by inorganic nanoparticles.
• The improvement in UV aging resistance is significantly influenced by surface modification of inorganic nanoparticles.

Three inorganic nanoparticles (nano-SiO2, nano-TiO2, nano-ZnO) were adopted to improve the ultraviolet (UV) aging properties of bitumen. Inorganic nanoparticles were surface modified by silane coupling agent. The compatibility between inorganic nanoparticles and bitumen was studied by high temperature storage stability test. More attention had been paid to the effect of surface modification on physical and UV aging properties of inorganic nanoparticles modified bitumens. The results showed that the compatibility between inorganic nanoparticles and bitumen was improved obviously by surface modification. Under the same content, the difference between the softening points as well as the nanoparticles contents in the upper and lower sections of the toothpaste tubes was decreased remarkably after surface modification. The penetration and ductility were decreased, while the softening point and viscosity of bitumen were increased with the addition of inorganic nanoparticles. However, this influence was weakened after surface modification of inorganic nanoparticles and the weakening effect of surface modified nano-ZnO was the most obvious. As a result of UV aging, softening point increment and viscosity aging index of bitumen were decreased by inorganic nanoparticles. The UV aging resistance of modified bitumen was further enhanced by surface modification of inorganic nanoparticles, and nano-ZnO modified bitumen showed the best UV aging resistance after surface modification.