Influence of Different Gypsum on Application Performance of Cement

Different types of gypsum have different influence on cement performance.In view of the difference of soluble characteristics between several types of gypsum,influence of different types of gypsum on application performance of cement,such as setting time,strength,compatability between gypsum and water reducers as well as formation of delayed ettringite(DEF),is analyzed.It is concluded that it is important to select certain types of gypsum in order to make full use of their actions on cement.In addition,it is suggested that it is necessary to further study the risk of DEF resulted from anhydrite,the compatibility between calcined gypsum and water reducer,and the limitation and disposal of impurity of chemical gypsum.