Effects of Nano C-S-H Content on Early Hydration of Cement at 10 ℃
The influence of nano C-S-H on the hydration process and development of early strength of cement at 10 ℃ was explored,and the mechanism of its early strength enhancement was analyzed.In this paper,nano C-S-H suspension was prepared by solution coprecipitation method,and it was mixed with ordinary Portland cement.The effects of nano C-S-H on setting time,flexural strength and compressive strength at 10℃were analyzed;Its effects on hydration process and hydration products were tested by XRD and TG.The initial setting time and final setting time were reduced by 9.9％and 10.4％when 0.05％of nano C-S-H was doped.Corresponding,the 24 h flexural strength and compressive strength increased by 34％and 33.5％.The addition of nano C-S-H resulted in a slight decrease in the 3 d strength.The content of Ca(OH)2 at 12 h,16 h and 24 h increased by 17.6％,21.3％and 29.6％,respectively,compared to the reference specimen.The addition of nano C-S-H can effectively promote the hydration process of C3 S to form more hydration products,shorten the setting time of cement and improve the strength of cement mortar within 24 h at 10 ℃.And no obvious decrease in 28 d compressive strength was observed.
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