Improvement of workability and early strength of calcium sulphoaluminate cement at various temperature by chemical admixtures

Effects of chemical admixtures on the workability and strength development of calcium sulphoaluminate cement (CSA) at various temperature were researched, of which mechanisms were analyzed by XRD and TG. The setting time and early strength of CSA were significantly improved by lithium carbonate-aluminum sulfate (LC-AS) at 0 °C and sodium gluconate-borax (SG-B) at 40 °C. LC-AS not only enhanced ettringite formation, but also accelerated belite hydration, and the amounts of ettringite was significantly increased at 0 °C. However, the formation of ettringite was retarded by SG-B, and the reduction of the amounts of ettringite can be achieved at 40 °C.