EFFECT OF CRYSTALLINE LAYERED SODIUM SILICATE ON THE ACCELERATION OF CEMENT HYDRATION AT EARLY AGE

Abstract

The study aimed at investigating on the effects of the crystalline layered sodium silicate on strength development of concrete. The hydration of cement mixed with the powder material was examined to evaluate applicability as an accelerating admixture. The test result confirmed that concrete mixed with the crystalline layered sodium silicate was higher compressive strength at early age than the control concrete without the powder material. Note is that the compressive strengths of the concrete at 28days were almost equivalent in all tested concrete. The reaction of alite in cement was accelerated by mixing the crystalline layered sodium silicate. Cement mixed with crystalline layered sodium silicate indicated earlier and higher hydration heat rate at the second-peak, and indicated higher hydration ratio than control cement paste. In hardened cement mixed with crystalline layered sodium silicate, a pronounced formation of acicular crystal was observed by SEM. Acicular crystal was also observed in the C₃A and gypsum hardened by crystalline layered sodium silicate. The observation confirms that the acicular crystal is ettringite. The study shows the hydration process, which contribute to strength development, of the concrete mixed with the crystalline layered sodium silicate.