Chemical Composition of CementThe raw materials used for the manufacture of cement consist mainly of lime, silica, alumina and iron oxide. . grinding. Table 1.4 shows the approximate oxide composition limits of ordinary Portland cement. Table 1.4. Approximate Oxide Composition Limits of Ordinary Portland Cement. Oxide . The average C3S content in.typical compostion of raw materials cement,COMPOSITION OF PORTLAND CEMENT - The ConstructorSep 16, 2011 . Composition of Portland Cement The principal raw materials used in the manufacture of cement are: a) Argillaceous or silicates of alumina in the form of clays and shales. b) Calcareous or calcium carbonate, in the form of line, chalk and marl which is a mixture of clay and calcium carbonate.