Hydration studies of cementitious material using silica nanoparticles

Abstract

In the present study, non-evaporable water (NEW) and degree of hydration (DOH) of cement paste in the presence of silica nanoparticles (SNPs) and silica fume (SF) have been investigated. The incorporation of SNPs increased the NEW content due to the formation of more amount of hydration products. On the basis of NEW content, DOH was also calculated at different time intervals and it was found to increase from 28% to 85% in SNPs modified cement, while with the addition of SF increment was 74% at 56 days of hydration. In addition, capillary porosity of SNPs incorporated cement paste was also calculated and observed ~75% reduction as compared to plain cement. These results attributed that the SNPs refines the pore structure as a result of pozzolanic reaction and formation of additional calcium-silicate-hydrate (C-S-H). FTIR results show the appearance of bridging silicate tetrahedral (Q2), characteristic peak at 970 cm-1 and a hump at ~1108 cm-1 due to the formation of polymerised C-S-H. The microstructure studies through SEM revealed that the SNPs refined the pore structure of the cement paste leading to denser microstructure as a result of more polymerized C-S-H gel formation, desirable for high strength and durability.