EFFECT OF NANO-SILICA INCORPORATION ON THE MECHANICAL AND DURABILITY PROPERTIES OF CONCRETE: A REVIEW

Abstract

Nano-silica (NS) has emerged as a significant supplementary cementitious material for enhancing concrete performance through its pozzolanic activity and nano-filler effects. When incorporated at optimal dosages (typically 1–3% by weight of cement), nano-silica improves both mechanical properties including compressive strength, flexural strength, and split tensile strength, as well as durability characteristics such as carbonation resistance, acid attack resistance, and rapid chloride penetration. [1] The addition of nano-silica particles considerably improves concrete mechanical properties, with compressive, flexural, and splitting tensile strengths increasing by 15.5%, 27.3%, and 19%, respectively, compared to control concrete. Optimal nano-silica content ranges from 2–3 wt%, with excessive replacements reducing improvements and even causing negative impacts on impact resistance and durability. [2] An appropriate nano-silica content of 2% contributes to dense pore structure and generation of more hydration products, resulting in enhanced impermeability with compressive strength of 43.53 MPa and improvements in chloride ion and water penetration resistance of 21% and 35%, respectively. [3] Self-compacting concrete with 2% nano-silica showed tensile strength improvements of 18.82% compared to control mix, with permeability tests exhibiting a decrease from 378 coulombs to 99 coulombs. Microstructural analysis revealed dense matrix with better development of calcium silicate gel. [4] The optimal nano-silica and graphene oxide combination (1.0% NS and 0.06% GO) enhanced compressive strength and lowered chloride ion permeability by 21.3% and 38.7%, respectively, when compared with control specimens, attributed to increased matrix density and improved interfacial bonding. [5]