Study on Preparation and Properties of Modified Magnesium Oxysulfate Cements

In this paper, the author researches on the preparation and properties of modified magnesium oxysulfate cements. The best basic ratio for magnesium oxysulfate cements is chosen by adjusting the concentration of magnesium oxysulfate and water binder ratio at the room temperature. Based on this ratio, five kinds of additives (phosphoric acid, sodium dihydrogen phosphate, Organic Acid Salt A, Organic Acid Salt B and compound additive) are selected to modify the cements. Experimental results show that all additives could improve the performances of magnesium oxysulfate cements. But compared with other additives, the compound additives could effectively improve the strength and water resistance of magnesium oxysulfate cements. In this experiment, this paper carries out the phase analysis of magnesium oxysulfate cements by means of SEM and XRD methods. The results show that the additives could improve the degree of cross- linking of the crystals, and there is a new phase in the cement with Organic Acid Salt A, Organic Acid Salt B and compound additives.