Effect of nanosilica on the hydration characteristics and compressive strength of blended basalt cement pastes

Abstract

THE EFFECTS of nanosilica (NS) on the hydration kinetics and mechanical strength development of blended basalt cement pastes of cementitious mixes were investigated. The measurements have been carried out on blended basalt cement pastes made with four dose levels of NS at different water to binder ratios. NS accelerates the hydration of blended basalt cement pastes. The addition of NS improves the mechanical strength and increases combined water contents, but free lime and bulk density decrease. Basalt acts as filled materials at early age and then its reactivity increases due to pozzolanic reaction. It has been concluded that partial substitution of blended basalt cement pastes up to 4 mass % NS improves the mechanical and hydration characteristics in comparison with the control hardened pastes up to 90 days. The results can be mainly attributed to the ultrafine nature of NS. The phases formed have already been confirmed with XRD and DTA.