New Calcium Silicate Hydrate Network

The seeding effect of finely dispersed calcium silicate hydrate (C-S-H) particles on tricalcium silicate hydration and on cement was investigated. An extremely small amount of C-S-H nuclei (0.3%) significantly increases the degree of hydration of both by promoting the growth of C-S-H clusters into the pore solution instead of around the tricalcium silicate or cement grains. Indeed, it was clearly shown that growth takes place around nuclei delivered by seeding materials and therefore in pore spaces. Nevertheless, some of the nuclei persist onto cement grains. The efficiency of seed suspensions for accelerating hydration is qualitatively related to the cluster size of nuclei formed during the synthesis and to the polymer type used to stabilize the smallest particles. Although early growth occurs in the pore solution, the mechanical properties of the cement pastes are preserved, and use of seeding consequently accelerates the strength development of mortars.