Effect of Different Lime-Anhydrite Ratios on the Hydration Process of Sulfoaluminate Cement

Abstract

In this paper, the influence of lime-anhydrite (L/A) ratio on the strength development, cement hydration, and setting time of calcium sulfoaluminate cement (CSA) is systemically investigated. Based on Raman spectroscopy and Thermogravimetric and differential thermal analysis (TG-DTA), the results showed that the hydration rate and the amounts and proportion of hydration products [monosulfate ettringe (AFm), ettringite (AFt), and AH3] were strongly influenced by L/A. When L/A was 1:3, the AFt formation was present by the fastest rate and accounted for the largest proportion of the whole hydration products, further resulting in the highest strength. When L/A≤1∶3, the process of cement hydration can be divided into induction, the formation of AFt and AFm, interconversion between AFm and AFt, and stabilization stage, respectively. However, when L/A>1∶3, there was no induction stage, and hydration process directly went into the accelerated period.