Effect of nano-silica particles on the hydration, the rheology and the strength development of a blended cement paste

Abstract

The aim of the present work is to evaluate the effect of nano-silica (NS) on the hydration, the rheology and the strength development of cement pastes. The advance of chemical reactions is monitored by mean of isothermal calorimetry and thermogravimetric analysis: adding nano-silica particles speeds up the hydration of the cement paste but alter its workability. Indeed, the effect of the nano-silica particles on the hydration kinetics can be modelled by accounting for its high specific surface and a flocculation model based on the DLVO theory is proposed so as to investigate the stability of nano-silica suspensions in the fresh cement paste. As a consequence, the dosage of nano-silica can be optimized to promote the early age strength. Lastly, a ternary blend incorporating fly ash can be designed so as to provide an early age strength similar to that of the cement while lowering the induced CO2 emissions.