Effects Of Calcium Sulphoaluminate Cement On The Performance And Mechanisms Of Magnesium Potassium Phosphate Cement

Magnesium potassium phosphate cement(MKPC)is a new kind of rapid setting cement,having the advantage of short setting time,high early strength and favorable bonding strength.For the engineering,especially for the rush repairment,MKPC based material is the best choice.However,the poor water stability of MKPC limits its application.To modify the MKPC,the calcium sulphoaluminate cement(CSA)was added,and the novel blended system was named as MKPC-CSA blended system.Furthermore,the compressive strength and water stability of the new system was investigated.The effects of CSA content on the setting time,compressive strength and water stability of MKPC-CSA blended system was studied,and the optimum mixture was achieved.Besides,the effects of different temperature and humidity of the environment on the MKPC-CSA blended system was studied.Furthermore,X-Ray Diffraction(XRD),Scanning Electron Microscope-Energy Spectrum(SEM-EDS)and Mercury Intrusion Method(MIP)were used to investigate the pore structure,reaction products,morphology and microstructure.The results showed:(1)The compressive strength and water stability of MKPC-CSA blended system was enhanced by the addition of CSA,and the optimum content was 20%~30%.(2)The MKPC-CSA blended system had a favorable environment adaptation.The early strength was seriously influenced by the environment temperature,while the late strength was hardly affected by it.The CSA and MKPC single system was seriously affected by the environment humidity,while the MKPC-CSA blended system was hardly affected by it.(3)The mechanisms of CSA modified MKPC mainly included filling effect,coating effect and interaction effect.