Study on properties of citric acid to magnesium oxysulfide cement

Magnesium oxysulfide cement (MOS) is an emerging building material. The application of MOS in practical engineering is affected by the low mechanical properties, which can now be modified by some admixtures. In this paper, the mechanical properties and hydration heat release of citric acid (CA)-modified MOS were studied, and the phase composition and microstructure of hydration products were analyzed by SEM and XRD. The results show that the addition of CA modified MOS can reduce MgO direct hydration of Mg(OH)2, promote the formation of a large number of needle-shaped 5Mg(OH)2 ·MgSO4·7H2O (5·1·7) phase crystals, and the compressive strength is greatly improved. When the CA dosage is 0.5%, the mechanics of MOS Best performance. The clotting time of the MOS modified with CA is slightly prolonged.