Thermoanalysis experimental study on rich-silica belite aluminosulphate cement

Richsilica belite aluminosulphate cement burned in the temperature of 1?200℃ in rough has higher strength than that burned in higher temperature. In order to look into the causes of this phenomenon, thermoanalysis of CaSO3·2H2O, CA,C4A3,C2S,C4AF and richsilica belite aluminosulphate cement are done on the basis of XRD analysis of document［1,2］. When the burning temperature of cement is below 1?200℃,C2S and C4A3 is not formed in large quantity and chemical combination rate of gypsum is only 4%, therefore the strength of cement is low. When the burning temperature of cement is above 1?250℃, gypsum begins to decompose and the decomposing rate of CaSO3·2H2O,C4A3 and richsilica belite aluminosulphate cement is 8%, 305% and 2668% respectively, which is not beneficial to the stable existence of C4A3, and even leads to the decomposing of C4A3 and lowers the cement strength eventually.