Effect of Colloidal Nano Silica on the Mechanical and Rheological Behavior of Blended Cement Pastes

Abstract

The nano-materials and nanotechnologies have highlighted the potential use of those materials in various fields such as medicine, construction, automobile industry, energy, telecommunications and informatics. The present works investigates the use of nano silica in cementitious pastes to improve the Rheological properties of the pastes along with this its effect on compressive strength of mixes is studied. Result reveal that colloidal nano silica reduced the setting time of cement paste made by using ordinary Portland cement (grade-43), Portland pozzolonic cement and slag cement. It is clearly observed the use of nano silica have reduced the initial setting time and final setting time of mixes by accelerating the cement hydration. NS also made the cement matrix stiff, hence making the use of superplastisizer compulsory. However, there is a particular level of superplastisizer beyond which, any further increases in superplastisizer dosage does not reduce the flow time of cement paste further. The effect of nano silica addition is large on the early age compressive strength of pastes.