Research Progress on Improving the Water Resistance of Magnesium Oxychloride Cement (MOC)

Magnesium oxychloride cement (MOC) is a promising alternative to Portland cement due to its superior mechanical strength and lower carbon footprint. However, its poor water resistance remains a major barrier to widespread use. This review critically evaluates recent and emerging modification strategies to overcome this limitation, with a specific focus on improving water durability through chemical and physical enhancements. The novelty of this work lies in the comprehensive analysis of synergistic effects from compound additives, particularly combinations of organic acids and phosphates, on MOC performance. For example, integrating 1% tartaric acid (TA) and phosphoric acid (PA) was found to increase compressive strength to 87 MPa and 100 MPa, respectively, while significantly improving the softening coefficient and reducing degradation under prolonged water exposure. The study also highlights the role of nano-modifications, fiber reinforcements, and polymer emulsions in densifying the microstructure and enhancing long-term durability. These insights offer a quantitative and practical roadmap for optimizing MOC formulations and advancing its use in sustainable construction applications.