Effect of Na2O·nSiO2 Nanodispersion on the Strength and Durability of Portland Cement Matrix

Abstract

The aim of the research is to investigate the effect of sodium silicate as nano-modifiers on the strength and durability of
Portland cement binder matrix. Three-component binding system consisting of colloidal sodium silicate solution (NSS),
superplasticizer suspension and Portland cement was used to determine properties of binder matrix. The effect of sodium
silicate was determined on the setting time, consistency, density, compressive strength and frost resistance of binder
matrix. The formation of nano-structure in cementitious composites under the influence of nano-modifiers (sodium
silicate solution, superplasticizer) was investigated. The compressive strength of hardened cement paste after 28 days
remains unchanged. The NSS has no effect on logarithmic law of strength increase with time. The compressive strength
accelerates the hardening process in later hardening period. In hardened cement paste with NSS ettringite crystals are
covered with amorphous phase, therefore increasing the closed porosity and frost resistance factor Kf.