Preparation and stabilisation mechanism of asphalt-in-water Pickering emulsion stabilised by SiO2 nanoparticles

In order to improve the performance property of emulsified asphalt, a particle emulsifier is introduced in this study. It serves both as the stabiliser and modifier for the asphalt. A new type of emulsified asphalt, the Nano-SiO2 stabilised asphalt, is prepared successfully. In this paper, a comparison of the stabilisation mechanism between the Pickering and the common emulsion is made. Then, based on the scanning electron microscope results, settlement, and Zeta potential tests, the wettability of the surface-modified Nano-SiO2 with a polycondensate material is analysed. Afterwards, the stable Nano-SiO2 emulsified asphalt is prepared. The stability mechanism of the emulsion is examined through a microscopic approach. Finally, the engineering indexes are tested on the Nano-SiO2 emulsified asphalt. It is revealed that except for the slightly sacrificed ductility, the Nano-SiO2 emulsified asphalt can meet the Chinese emulsified asphalt specification, with improved stability, penetration, and softening point of the residual after evaporation. This study verifies the feasibility of using the Nano-SiO2 as an asphalt emulsifier for preparing Picking emulsions.