In the competition of present era where concrete plays an important role in construction industry, many of its limitations were studied and to improve it many admixtures were developed, like mineral admixture, chemical admixture etc. An effort is made to study some of the mineral admixture like Ground granulated blast furnace slag and their effect on the plain cement concrete. Compressive strength and Flexural strength of ground granulated blast furnace slag cement concrete with different dosage of slag was studied as a partial replacement of cement.