Effect of Curing Temperature on Hydration of Calcium Aluminate Cement–Calcium Sulfate–Limestone System

Abstract

The effect of curing temperature on hydration of a ternary blend of calcium aluminate cement (CAC), calcium sulfate (C$), and limestone (Cc) was examined. Compressive strength was evaluated at 1, 7, and 28 days. Hydration kinetics and products were assessed using calorimetry, thermogravimetric analysis, and X-ray powder diffraction. It was found that elevating the curing temperature from 5 to 50°C accelerated cement hydration. At 5 and 23°C, the incorporation of limestone caused a transformation of monosulfoaluminate into monocarboaluminate in the hydration product at 28 days. Higher curing temperatures (35–50°C), however, resulted in a collective increase in monosulfoaluminate, monocarboaluminate, and aluminum hydroxide, and led to a significant reduction in ettringite. Higher curing temperatures also led to an increase in aluminium hydroxide but did not form as much hydrogarnet (C3AH6) in the CAC-C$-Cc system as in the CAC-C$ system. This study provides a technical reference for practical design of materials based on the ternary binder system.