Impact of Nano-silica on the hydration, strength, durability, and microstructural properties of concrete: A state-of-the-art review

Concrete significantly impacts the atmosphere as its primary raw material, Portland cement, determines a considerable proportion of carbon dioxide in its production process. Improving the strength and durability properties of concrete buildings could decrease their influence on the atmosphere. Adding a small proportion of Nano-silica (NS) to concrete could change concrete's configuration at the Nano level. Compared to other nano-materials, Nano-silica has riveted a lot of consideration due to its pozzolan reaction with calcium-hydroxide to make a gel of calcium -silicate-hydrate. Nano-silica can promote the adhesion between the concrete's binder and aggregate by coupling and efficiently enhancing and densifying the concrete's matrix. The present review article focuses on studying the influence of different types and proportions of nano-silica on the hydration, strength, durability, and microstructural characteristics of different cement -based concrete. This review article shows that around 2-4 % of Nano-silica in various types of concrete is suitable to improve the influence of NS on the physical, durability, and mechanical properties and densify concrete microstructure. Also, the present challenges that the concrete industry is facing in the commercial utilization of nano-silica in concrete are discussed in this review article. It is established that this review article will produce novel concepts to endorse the practical utilization of Nano-silica in the construction sector and offer some productive designs for similar research studies in the future.