In the present study, belite sulfoaluminate (BSA) clinkers containing varying levels of free calcium sulfate (f-CaSO)—specifically 0 %, 5 %, and 10 %—were synthesized. These clinkers were subsequently mixed with anhydrite and gypsum for comparative analysis. Utilizing a range of analytical techniques such as isothermal calorimetry, X-ray diffraction (XRD), and thermogravimetric analysis (TGA), the early hydration process and the constitution of hydration products were systematically investigated. The experimental data reveal that sulfate-rich BSA clinkers demonstrate enhanced hydration activity, as well as superior early compressive strength. As the f-CaSO content escalates, there is a corresponding increase in the cubic crystal sulfoaluminate within the BSA clinkers. This compositional shift has a beneficial impact on both the initial and final setting times, thereby enhancing the 3-day compressive strength. Contrary to ordinary BSA cement clinkers, those rich in sulfate retard the dissolution rate of external gypsum. It is noteworthy that anhydrite, possessing a solubility greater than gypsum, exerts a more pronounced acceleration effect on the early hydration process of sulfate-rich BSA clinkers.

中文翻译：

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游离硫酸钙含量对富硫酸盐贝利特硫铝酸盐熟料早期水化的影响：与硬石膏和石膏的比较研究

在本研究中，合成了含有不同水平游离硫酸钙 (f-CaSO)（具体为 0%、5% 和 10%）的贝利特硫铝酸盐 (BSA) 熟料。随后将这些熟料与硬石膏和石膏混合以进行比较分析。利用等温量热法、X射线衍射（XRD）和热重分析（TGA）等一系列分析技术，系统地研究了早期水化过程和水化产物的构成。实验数据表明，富含硫酸盐的 BSA 熟料表现出增强的水化活性以及优异的早期抗压强度。随着 f-CaSO4 含量的增加，BSA 熟料中立方晶体硫铝酸盐的含量相应增加。这种成分变化对初始和最终凝固时间都有有益的影响，从而提高了 3 天的抗压强度。与普通 BSA 水泥熟料相反，富含硫酸盐的水泥熟料会延缓外石膏的溶解速度。值得注意的是，硬石膏的溶解度大于石膏，对富含硫酸盐的 BSA 熟料的早期水化过程具有更明显的加速作用。