Concrete is a very complex material. Its properties as fresh as well hardened concrete is a function of the right mix of constituents of concrete, which if not done properly will adversely affect the properties of concrete. Hence the right judicious proportion of all the constituents is most important.
Therefore, the scientific and systematic process of choosing economical relative proportion of various ingredients from available material which gives cohesive concrete of the desired workability in fresh stage and desired strength and durability in the hardened stage. It is the step by step procedure for selection of water-cement ratio, water content and estimation of coarse aggregate content and fine aggregate content done in a laboratory with actual material which is going to be used.