Modified cementitious materials incorporating Al2O3 and SiO2 nanoparticle reinforcements: An experimental investigation

This research presents the improvement effect and influence mechanism of nano-Al2O3 (NA) and nano-SiO2 (NS) on concrete performance from the macro and micro scales. The crucial parameter investigated in this research is the various concentrations of the nano-reinforcement 1, 2, and 3 wt. % of cement, the results show that NA and NS can improve the compressive strength and resistance to chloride penetration (RCP) ability of concrete, the amount of 1 and 2 wt. % exhibiting the best effect, especially in terms of compressive strength, which can be increased by more than 20%. As nanoscale particles, NA and NS can fill the capillary pores in concrete and can also promote the cement hydration to produce more C-S-H gel, thereby reducing the total porosity of concrete by about 2%, making its internal pores and cracks less and the microstructure denser. Based on the correlation analysis, the most important factors affecting the compressive strength and RCP ability of concrete were found, and the linear relationship equation between compressive strength and RCP ability was obtained.