Basic magnesium sulfate cement (BMSC) is a new type of magnesium cementitious material with the core of admixture technology. It is mainly made up of lightly burned magnesia, magnesium sulfate, mineral admixture of different crystal water and chemical admixture. It is used in the same way as ordinary Portland cement. Basic magnesium sulfate cement has similar advantages with magnesium oxychloride cement, such as light weight, fast setting, high strength, wear resistance, and is not easy to absorb moisture and anti-halogen. The solubility of its main hydration product 5Mg(OH)2•MgSO4•7H2O phase (5•1•7 phase) is only 0.034 g/100 g water, which is basically the same as Portland cement, much lower than magnesium oxychloride cement, which can widely replace magnesium oxychloride cement in the field of building insulation materials. In addition, the BMSC's flexural strength is 2-3 times than that of the Portland cement at the same strength grade, and its durability and reinforcement protection performance is similar to Portland cement. Besides, BMSC concrete has large rigidity, good seismic performance and its bending, tensile and impact resistance performance are better than that of the Portland cement concrete at the same grade, which also has a good application prospect in the field of structural engineering. More importantly, the calcination temperature of light burned magnesia used to prepare BMSC is low, which makes BMSC meet the requirements of building energy conservation and environmental protection, and is expected to become the core high-performance eco-friendly cement in the future with great development potential. In this paper, the preparation and hydration process of BMSC are reviewed. The microstructure and performance difference of BMSC, magnesium oxychloride cement and magnesium oxysulfate cement are compared and analyzed. The effects of content and activity of α-MgO in the magnesium materials, the proportioning molar ratio of α-MgO/MgSO4 and H2O/MgSO4, the type and dosage of chemical admixture on the microstructure and properties of BMSC are clarified. On this basis, measures to furtherly improve the performance of BMSC are proposed from the aspects of raw materials and preparation processes. © 2020, Materials Review Magazine. All right reserved.
