Exploring the influence of SiO2 and TiO2 nanoparticles on the mechanical properties of concrete

The compressive strengths of concrete containing different contents of nano-SiO2 and nano-TiO2 have been investigated at ages of 3, 7, 21 and 28 days. Scanning electron microscopy and X-ray diffraction are used to evaluate the hydration products and paste-aggregate interface. The results indicate that both nano-SiO2 and nano-TiO2 can act as crystallization centers of calcium hydroxide and as fillers in the empty space, reduce the size of crystal at the interface and improve the compressive strength at 28 days. Also, both of them can react with calcium hydroxide, but only nano-SiO2 can produce C-S-H and enhance the early strength.