A comprehensive overview about the effect of nano-SiO2 on some properties of traditional cementitious materials and alkali-activated fly ash

Application of nano-SiO2 (NS) in cementitious materials has drawn much attention, due to the increased demand for new materials with attractive properties. Traditional cementitious materials based on Portland cement (PC) and alkali-activated fly ash (AAFA) systems were improved by applying NS aiming to develop a novel, smart and environment. This paper presents an overview of the previous works carried out on using NS into the traditional cementitious materials based on PC and AAFA. Heat of hydration, workability, setting time, strength, abrasion resistance, freeze-thaw resistance, fire resistance, drying shrinkage, resistance to aggressive environmental, leaching, water absorption, chloride penetration and permeability of PC-based materials modified with NS as well as comparison between NS and other nano types have been reviewed. In addition, previous works curried out on setting time, compressive strength and permeability of AAFA-based materials modified with NS have been reviewed.