The effect of additions of alkaline-earth metal chlorides on the setting behavior of a refractory calcium aluminate cement

Abstract

The literature concerned with the effect of alkaline and alkaline-earth metal chlorides on the hydration of calcium aluminate cements is confused. For example, some authors have suggested that magnesium chloride acts as a retarder, while others stated that it acts as an accelerator. Accordingly a thorough investigation has been carried out into the setting behaviour and early hydration of Secar 71, mixed with a range of concentrations of MgCl 2, CaCl 2, SrCl 2, and BaCl 2. At 12 °C all chlorides brought about retardation of the setting time of the cement, which increased with increasing concentration of the admixture. At 20 °C, at low concentrations they brought about acceleration of the set, but acted as retarders at higher concentrations. At 28 °C and 36 °C, retardation was observed and its extent increased with increasing concentration of the admixture.