Hydration of tricalcium silicate in the presence of synthetic calcium–silicate–hydrate

The 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 29Si 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 C3S. 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 C3S particles.L?hydratation aux jeunes \ue2ges du silicate tricalcique, principal compos\ue9 du ciment Portland, a \ue9t\ue9 \ue9tudi\ue9e en pr\ue9sence d?une addition d?hydrate de silicate de calcium (C-S-H) synth\ue9tique ayant des rapports C/S de 0,8 et de 1,2. On a employ\ue9 la calorim\ue9trie isotherme \ue0 conduction, la microscopie \ue9lectronique \ue0 balayage, l?analyse calorim\ue9trique \ue0 compensation de puissance et la RMN (r\ue9sonance magn\ue9tique nucl\ue9aire) MAS du 29Si dans le but d?investiguer les \ue9v\ue9nements qui surviennent au cours des divers stades de l?hydratation. Les r\ue9sultats qui ont \ue9t\ue9 analys\ue9s \ue0 l?aide de m\ue9thodes innovatrices du domaine de la chimie cimentaire ont r\ue9v\ue9l\ue9 que l?addition de grains de C-S-H synth\ue9tique acc\ue9l\ue9rait de fa\ue7on appr\ue9ciable l?hydratation du C3S, acc\ue9l\ue9ration qui \ue9tait tributaire de la quantit\ue9 et de la composition chimique de l?addition. Il est donn\ue9 \ue0 penser que le C-S-H synth\ue9tique accro\ueet significativement la vitesse et le degr\ue9 de dissolution des particules de C3S.Peer reviewed: YesNRC publication: Ye