A reaction range for hydration of calcium sulfoaluminate with calcium sulfate and calcium hydroxide: theory and experimental validation

To better investigate and understand the hydration of calcium sulfoaluminate (CSA) cement, a theory reaction range for the hydration of CSA with calcium sulfate and calcium hydroxide was established by theoretical calculation with a hypothetical hydration reaction system. With different amounts of calcium sulfate and calcium hydroxide in the reaction systems, their hydration processes, hydration products and stoichiometric water/solid ratios showed regular changes. A preliminary experimental validation was made by analysing the hydration products (curing time 28 d and water/solid ratio of 10) of several composition points in the theory reaction range by means of x-ray diffraction and thermogravimetric analysis. The process for calculation of the theory reaction range and some of the experimental validation results are presented in this paper.