Quantification and characterization of C-S-H in silica nanoparticles incorporated cementitious system

This paper presents the quantification and nanomechanical properties of calcium silicate hydrate (C-S-H), formed at early stage hydration of tricalcium silicate (major cement phase) in presence of silica nanoparticles (SNPs). SNPs showed dominant nucleation effect at 8 h and pozzolanic effect at 24 h and accelerate the hydration rate (∼83% at 8 h and ∼51% at 24 h) due to the formation of additional C-S-H nuclei. Further, 29Si-NMR and FTIR techniques showed the acceleration in polymerization of silicate chain leading to the formation of tobermorite like structure. Formation of polymerized and crystalline C-S-H gel in presence of SNPs increases the percentage of high density C-S-H (∼40%) and lowers the low density C-S-H (∼52%) at 24 h of hydration, as observed in nanoindentation results.