Water Resistance of Basic Magnesium Sulfate Cement

Abstract

Water resistance of basic magnesium sulfate (BMS) cement has been studied in this paper. The solubility of main hydration of 5Mg(OH)2·MgSO4·7H2O in BMS cement has been analyzed by analyzing ions changes in 5Mg(OH)2·MgSO4·7H2O solution. Compressive strength and softening coefficient changes of BMS cement after immersing in water have been tested to evaluate water resistance of BMS cement. And crystal compositions and microstructure of BMS cement before and after immersing in water has been analyzed by XRD and SEM to study the mechanism. These results show that 5Mg(OH)2·MgSO4·7H2O possesses a low solubility at room temperature. Basic magnesium sulfate cement displayed an excellent water resistance based on additives in basic magnesium sulfate cement can inhibit the hydration of hard burnt MgO to sheet-like Mg(OH)2 and reduce crystallization stress in BMS cement.