With the advantages of rapid setting, high strength and durability properties, calcium sulfoalu-minate (CSA) cement is usually used as rapid repairing material and grouting material in building and other engineering projects. In order to improve the physical properties of CSA grouting materials, the effect of adding sodium aluminate and quicklime was investigated through hy-dration heat, DTA-TG, XRD and SEM. Their effects on the kinetics of ettringite formation in CSA grouting materials were analyzed. The results show that with the increase of sodium aluminate in Slurry A (CSA cement paste) from 0% to 1.5% (by weight of CSA cement), the setting time of the grouting materials gradually shortened, the compressive strength at early ages (2 h and 3 days) rapidly increased, but the compressive strength at 28 days decreased continuously. The greatest compressive strength was achieved when 20% quicklime and 80% anhydrite were used in Slurry B (quicklime + anhydrite paste). The results from hydration heat, DTA-TG and XRD show that the formation of ettringite (AFt) was accelerated at early ages by sodium aluminate and quicklime, and quicklime could accelerate the formation of AFt at all ages. It was found that sodium aluminate only accelerated the early formation of ettringite but did not affect the overall amount of hydration products, and the initial accelerated hydration could provide a proper structural layout for the later strength development.

CSA cement is usually used in grouting materials because of its fast setting and high early strength properties. This paper focuses on the effects of sodium sulfate and potassium sulfate on the hydration mechanism and properties of calcium sulfoaluminate (CSA) cement based double liquid grouting materials (DLGM). A comprehensive experimental program including XRD, TG-DTA, hydration heat, scanning electron microscope (SEM) and mechanical tests were performed. The results show that both sodium sulfate and potassium sulfate accelerated the hydration of CSA cement and the formation of ettringite from the very beginning and shortened the initial and final setting time of DLGM. The changing behaviors of setting time, hydration heat and strength of DLGM with sodium sulfate and potassium sulfate were found to be different and their optimum contents were also different. The microstructure observation shows that the addition of sodium sulfate made the ettringite merged as plate-like, and potassium sulfate generated longer ettringite strips stacked together in DLGM. By considering both setting time and compressive strength, the recommended adding amounts of sodium sulfate and potassium sulfate are 3% and 1.5%, respectively. These findings could contribute to the adjustment of physical properties of DLGM.