Due to lightweight, high-strength, and high toughness properties, Basic magnesium sulfate cement (BMSC) can be widely used in producing various structural and decorative products. Most current research only focuses on the performance of BMSC under room temperature. However, low temperature environments may have a serious impact on the performance of BMSC, such as during cold seasons or in salt lake cold regions with abundant magnesium resources, so the performance of BMSC in low temperature environment needs to be explored to expand its application. This study investigated the influence of different low temperatures (−5 to 20°C) on the compressive strength and water resistance of BMSC cement. The phase composition, microstructure and pore structure of BMSC has been analyzed using XRD, QXRD, TG/DTA, SEM, BSEM/EDS Mapping and MIP. The Results indicate that the low hydration rate, precipitation of magnesium sulfate, increase in porosity and decrease in 517 phase content are the main reasons for the low strength of BMSC under low temperature curing. Although hardened BMSCs cured at low temperatures can continue to hydrate in water to form strength phases, corrosion and cracking may occur. Replacing light burned magnesite with high active magnesium oxide can significantly improve the mechanical properties of low temperature cured BMSC. However, low temperatures reduced the crystallinity of the 517 phase, thereby increasing its water solubility and lead to poor water resistance of BMSC.

碱式硫酸镁水泥（BMSC）具有轻质、高强、高韧性的特点，可广泛用于生产各种结构和装饰制品。目前大多数研究仅关注BMSC在室温下的性能。然而，低温环境可能会对BMSC的性能产生严重影响，例如在寒冷季节或镁资源丰富的盐湖寒冷地区，因此需要探索BMSC在低温环境下的性能以扩大其应用。本研究研究了不同低温（-5至20°C）对BMSC水泥的抗压强度和耐水性的影响。使用 XRD、QXRD、TG/DTA、SEM、BSEM/EDS Mapping 和 MIP 分析了 BMSC 的相组成、微观结构和孔结构。结果表明，水化速率低、硫酸镁沉淀、孔隙率增加和517相含量减少是BMSC低温养护强度低的主要原因。尽管在低温下固化的硬化 BMSC 可以继续在水中水合形成强度相，但可能会发生腐蚀和开裂。用高活性氧化镁代替轻烧菱镁矿可以显着提高低温固化BMSC的力学性能。然而，低温降低了517相的结晶度，从而增加了其水溶性，导致BMSC的耐水性较差。