Hydration of tricalcium silicate in the presence of synthetic calciumsilicate-hydrate Alizadeh, Rouhollah; Raki, Laila; Makar, Jon M.; Beaudoin, James J.; Moudrakovski, Igor http://www.nrc-cnrc.gc.ca/irc H ydra t ion of t ric a lc ium silic a t e in t he pre se nc e of synt he t ic c a lc iumsilic a t e -hydra t e
NRCC-51324Alizadeh, R.; Raki, L.; Makar, J.M.; Beaudoin, J.J.; Moudrakovski, I.
September 2009A version of this document is published in / Une version de ce document se trouve dans:Journal of Materials Chemistry, v. 19, no. 33, September 9, 2009, pp. 1-19, DOI: 10.1039
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AbstractThe early age hydration of tricalcium silicate, the main chemical compound in Portland cement, was studied in the presence of synthetic calcium silicate hydrate (C-S-H) addition having C/S ratios=0.8 and 1.2. Isothermal conduction calorimetry, scanning electron microscopy, differential scanning calorimetry and 29 Si MAS NMR were employed in order to investigate events occurring during various stages of the hydration. The results that were analyzed using novel methods in cement chemistry showed that the addition of seeds of synthetic C-S-H significantly accelerated the hydration of C 3 S. The extent of the acceleration was dependant on the amount and chemical composition of the C-S-H seeds. It was suggested that the synthetic C-S-H significantly increased the rate and degree of dissolution of the C 3 S particles.It was also found that the nucleation and silicate polymerization of the C-S-H that formed during the hydration of the C 3 S phase was promoted. Direct evidence of the seeding effect was provided. The properties of the resulting C-S-H hydration products seemed to be dependant on the lime to silica ratio of the synthetic C-S-H. It was suggested that the silicate polymerization and chemical composition of the hydration products of silicate phases may be manipulated through C-S-H seeding. As the chemical and mechanicalproperties of C-S-H are largely controlled by its C/S ratio, this method should provide a unique tool for tailoring the nanostructure of the hydration products of Portland cement through the addition of selective C-S-H seeds for optimum engineering and durability performance.Keywords: Tricalcium Silicate (C 3 S), Calcium Silicate Hy...
