(a) The portland cement consists of tricalcium silicate (3‌CaO⋅SiO2), dicalcium silicate (2‌CaO⋅SiO2), tricalicium aluminate (3‌CaO⋅Al2O3) and tetra-calcium aluminoferrite (4‌CaO⋅Al2O3⋅Fe2O3). Hence, the major constituent in it is CaO and SiO2. The percentage of CaO≈64% and SiO2 is 21%.