The properties and hydration of Portland cement containing calcium sulfoaluminate cement

Calcium sulfoaluminate (CSA) cement has some attractive qualities, such as rapid setting, high early strength, and micro-expansion. It was commonly used to improve properties of Portland cement (PC). In this paper, the investigated results show that the setting times are notably reduced as the CSA cement content is increased. The compressive strength is slightly lower for the PC–CSA blends containing less than 10 % CSA cement, but notably lower for the PC–CSA blend containing 20 % CSA cement when compared to PC. High amounts of CSA cement significantly delay the hydration of alite, thereby increasing the porosity. Furthermore, the addition of CSA cement changes the ettringite morphology.