Effect of SiO2 and ZnO Nano-Composites on Mechanical and Chemical Properties of Modified Concrete

In the present study, Nano Silica (n-SiO 2 ) as cementitious nanomaterial and Nano Zinc Oxide (n-ZnO) as non- cementitious nanomaterial in powder form are doped in the concrete mix to replace the cement by 0.5%, 0.75% and 1.0%. The specimens were casted with a constant Water Cement (W/C) ratio of 0.45 with an M25 mix design. From the experimental results, n-SiO 2 additives with 0.75% replacement and n-ZnO with 0.5% replacement increase the compressive strength by 16.54% and 6.32% and split tensile strength by 19% and 3.86% respectively as compared to the normal concrete. Hydration of Tricalcium Silicate (C 3 S) is a significant part of Bogue’s compound. Therefore, in the hydration process reactions of nanomaterials with C 3 S were investigated in this study. Additional cement gel formation due to n-SiO 2 helps to increase compressive strength as well as durability of concrete. The formation of the Zn(OH) 2 layer in the hydration process resists the water in cement. Due to doped nanoparticles, the size acid resistance properties of concrete are increased up to some extent but loses the concrete strength. With the help of optimized composition, the exact constituent of concrete can be easily identified for cementitious and non-cementitious nanomaterial. After that Ultrasonic Pulse Velocity (UPV) test was carried out for tap water and acidic media. The n-SiO 2 additives, concrete shows an excellent quality as compared to n-ZnO additives. As per UPV test results, n-SiO 2 additives are more suitable to use in the concrete. The outcome of this study will be helpful to the construction industry in understanding the effect of nano-composite in concrete.