Discuss the role of gypsum during the manufacturing of Ponland cement.
C3A readily combines with water and liberates a large amount of heat. The added gypsum retards the dissolution of C3A by forming insoluble calcium sulpha-aluminate 3CaO .AI203 . .xCaS04 .7H20. This reaction prevents high concentration of alumina in the cement solution which retards the early initial set of the cement.