Abstract Supersulfated cements (SSCs) are composed primarily of blast furnace slag, calcium sulfate, and a small content of alkaline activator. SSC has been discussed in the literature because it has a low content of clinker and consequently low CO2 emissions. However, the current absence of durability studies is the main challenge for the large-scale implementation of SSC as a building material. The objective of this study was to investigate the behavior of phosphogypsum-based SSC mortar under sulfate attack. SSC mortars were submitted to MgSO4 and Na2SO4 solutions. Portland cements were also used as a comparison. SSC mortar showed good durability against sodium sulfate attack but presented an expansive behavior when exposed to magnesium sulfate. This behavior in the MgSO4 solution was attributed to the low portlandite reserve, which anticipated the attack of C-S-H. Besides, the non-formation of the brucite layer accelerated the entry of this type of sulfate.

中文翻译：

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磷石膏基过硫酸盐水泥砂浆抗硫酸钠和硫酸镁外部侵蚀的耐久性

摘要 过硫酸盐水泥（SSCs）主要由高炉矿渣、硫酸钙和少量碱性活化剂组成。文献中已经讨论过 SSC，因为它的熟料含量低，因此 CO2 排放量低。然而，目前缺乏耐久性研究是大规模实施 SSC 作为建筑材料的主要挑战。本研究的目的是研究磷石膏基 SSC 砂浆在硫酸盐侵蚀下的行为。将 SSC 砂浆置于 MgSO4 和 Na2SO4 溶液中。波特兰水泥也用作比较。SSC 砂浆对硫酸钠的侵蚀表现出良好的耐久性，但在暴露于硫酸镁时表现出膨胀行为。MgSO4 溶液中的这种行为归因于低硅酸盐储量，这预示着 CSH 的攻击。此外，水镁石层的未形成加速了此类硫酸盐的进入。