Delayed Strength Development of Composite Cementitious with Calcium Silicate Slag

摘要

Using pulverized calcium silicate slag (CSS) to replace part of Portland cement (PC) as composite cementitious material is the most energy-saving and clean treatment method. The main objective of this study was to investigate the delayed strength development of the CSS-PC composite cementitious. The compressive strength of the composite cementitious with 10 to 40 CSS was tested, the delayed strength was calculated, and the delayed age was analyzed. Results showed that the delayed strength and delayed age increased with the increase in the substitution rate of CSS, which was determined by the ratio of C_2S and C_3S. Moreover, a compressive strength prediction model of CSS-PC composite cementitious was established based on the "core-shell" hydration model. The calculated value was compared with the specification value of each country to analyze whether the compressive strength of CSS-PC composite cementitious meets the engineering requirements.