Hydration effect of sodium silicate on cement slurry doped with xanthan

The effect of polyhydroxy xanthan on the corresponding hydration process of cement and regulation mechanism was discussed, then sodium silicate as coagulant was added into the xanthan-retarded cement paste and its accelerating mechanism for the retarding effect of xanthan was investigated. The results indicate that due to chemisorption between hydrophilic hydroxyl and carboxyl and calcium ions, the core-shell construction of xanthan-cement to a certain extent hinders the hydration process of cement particles, adding sodium silicate in the cement-added xanthan significantly inhibits the retardation of the xanthan, shortens the setting time of the retarding cement, improves the compressive strength of the retarded cement, and to some extent promotes the hydration of C(3)A. The early hydration of C(3)A, C3S and sodium silicate rapidly formed a large amount of C-S-H, which was bound with the ettringite skeleton to promote coagulation hardening of the cement slurry, further established a "suppression-ex citation" system between xanthan and sodium silicate in cement slurry. (C) 2019 Elsevier Ltd. All rights reserved.