Effect of Nano-TiO2 at macro and micro level of concrete by partial substitution of cement

At macro level, the strength of the concrete will decline due to several reasons like high water-cement ratio, improper compaction, and improper curing. At micro level, concrete strength will reduce due to poor pore structure. Since the cement acts as a binding agent upon reacting with water, the fineness of the cement influences the strength. Higher water-cement ratio leads to higher porosity. Fine particles of very high specific surface area may affect the pores of concrete, leading to strength enhancement rather than decline. In this study, the effects of partial substitution of nano-TiO₂ for cement into concrete on mechanical strength and microstructure are investigated. Fresh and hard macro-level properties are studied for M40 and M60 with cement replacement from 0% to 2% by nano-TiO₂. SEM images were examined for studying dispersion of particles, and XRD was used for analyzing the products of hydration at micro level. It is found that at 1% of nano-TiO₂, the strength for M40 and M60 was higher compared to other percentage replacements.