Effect of nano SiO2 on mechanical properties of micro-steel fibers reinforced geopolymer composites

Abstract This paper presents the mechanical properties of micro steel fiber reinforced fly ash geopolymer composites containing different amounts of nano-silica. Four different fly ash-based geopolymer composites (GPC) are prepared by using a fixed amount of micro-steel fibers (0.5% by weight) and four different amounts of nano silicon dioxide (SiO2) consisting of 0%, 1%, 2%, and 3% amounts by weight. The GPC with 0% nano SiO2 having 0.5% micro-steel fibers is taken as the control mix. Different mechanical and microstructural properties of fabricated GPC are examined by assessing their stress-strain behavior, compressive strength, flexural strength, bending load-deflection behavior, impact strength, fracture toughness, toughness modulus, elastic modulus, toughness indices, hardness, and scanning electron microscopy (SEM). The outcomes of tests depicted that the addition of nano SiO2 significantly enhanced the mechanical properties and microstructure of micro-steel fiber-reinforced GPC by producing a denser matrix and refining the interfacial zones. According to the results of this study, the recommended amount of nano SiO2 to be utilized in GPC for the optimal behavior is 2%.