Enhancements and mechanisms of nanoparticles on wear resistance and chloride penetration resistance of reactive powder concrete

In this paper, nano-SiO2 (NS), nano-TiO2 (NT) and nano-ZrO2 (NZ) at contents of 1% and 3% were adopted to improve the wear resistance and chloride penetration resistance of reactive powder concrete (RPC) with room temperature cuing or heat curing. The modification mechanisms of nanoparticles on RPC properties were investigated through X-ray powder diffraction analysis, thermogravimetric analysis, scanning electron microscopy observation and 29Si Nuclear Magnetic Resonance spectra analysis. Research results show that the wear resistance and chloride penetration resistance of RPC incorporating with nanoparticles are significantly improved because the addition of NS/NT/NZ can modify the microstructures of RPC. The abrasion loss per unit area of 3 wt% NZ filled RPC with heat curing is increased by 48.46% compared with the control RPC. The chloride diffusion coefficient of RPC containing 3 wt% NT, 1 wt% and 3 wt% NZ with room temperature curing can be decreased to 0. The heat curing is more beneficial to improve the wear resistance of RPC containing NS/NT/NZ than room temperature curing, while room temperature curing is more effective to improve the chloride penetration resistance.