The effect of low temperature phase change material of hydrated salt on the performance of magnesium phosphate cement

Magnesia-phosphate cement (MPC) is a new type of excellent repairing material, and its short setting time has great influence on its engineering wide application. In this paper, on the basis of Borax retarder, and according to the high hydration heat release characteristic of MPC, low temperature phase change material (PCM) of CaCl2·6H2O was chosen to improve the performances of MPC. The results indicated that the performances of MPC have been greatly optimized by adding the PCM of CaCl2·6H2O. For instance, the PCM can decrease the hydration rate, prolong the setting time, and reduce the content of harmful pore, and also it can improve the strength of MPC. Nevertheless, when the dosage of PCM is more than 1.5%, the strength and flow-ability of MPC will be decreased. Taking all aspects into consideration, the best performance of MPC is when the PCM dosage is at 1.5%.