Influence of Several Calcareous Compounds on the Performance of Sulphoaluminate Cement Paste

In order to clarify the adaptability of sulphoaluminate cement (SAC) and to improve the quality of SAC construction, several common calcareous compounds including calcium chloride, calcium sulphate and calcium hydroxide in designed content were introduced to SAC paste, respectively, following by the investigations of the corresponding fluidity degree and setting time. The experimental results show that calcium chloride in relative high content (no less than 1%) accelerates the cement setting, along with an enlarged degree of fluidity. As a comparison, the involvement of calcium sulphate in SAC paste does simply play a role of setting retarder by prolonging the setting time and enlarging the fluidity degree simultaneously. On the other hand, the presence of calcium hydroxide in SAC paste results in a state of being “neither setting nor flowable”, since the corresponding SAC paste shows a prolonged setting time and a remarkably lowered degree of the initial fluidity degree. All the phenomena can be explained from the viewpoints of hydration mechanism of dehydrated calcium sulphoaluminate.