Nanopowders as an additive for strength and durability enhancement of cement composite: Review and prospects

Abstract

The interest in utilizing nanopowders in concrete to increase the mechanical characteristics of concrete, such as compressive strength and tensile strength, is gaining importance. The commonly used nanopowders to enhance composite properties are nano-SiO2 (nano-silica), nano-Fe2O3 (nano-ferric oxide), nano -TiO2 (nano-titanium oxide), nano clay, nano-Al2O3 (nano-alumina). Nanopowders are the perfect additive due to their smaller size (1 nm to 100 nm), high level of reactivity, and greater surface area than cement. Hence, the mechanical characteristics of cement-based materials with embedded nanopowders are reviewed in this article. By virtue of the low water-to-cement ratio, nanopowders are utilized to upgrade the strength and workability of the concrete. The review examined the impact of nanopowders on the enhancement of the strength, durability, and cost-effectiveness of concrete. Due to its strong reactivity, nanopowder increases the mechanical (compressive strength, flexural strength, tensile strength, and modulus of elasticity) and durability (resist weathering action, abrasion, chemical attack) properties of the cement composite. The addition of nanopowders to concrete increases the pozzolanic content and surface energy of the cement composite, resulting in the durability enhancement of the cement composite. This article explored that incorporating nanoparticles into concrete enhances its strength by 25 to 40 % on the seventh day and 7 to 14 % on the 28th day, as well as enhances the workability of the cement composite. However, the excessive concentration of nanoparticles causes particle agglomeration, which decreases the strength and durability of the cement composite. Thus, the review concludes that using nanomaterials in concrete is more favorable concerning of strength and durability advancement of the composite, as it improves their qualities and accelerates the hydration process.