Due to an increase in population, there is a rapid rise in industrialization and urbanization in the country which marshalled the way for infrastructure development which has resulted in heavy usage of natural resources such as Fine Aggregates (Sand), Coarse Aggregates, etc. which are non-renewable. In this paper, we discuss about a method for reusing the plastic wastes and as well as safeguarding the natural aggregates by incorporating them into concrete. It aims at finding out the optimum percentage replacement for natural coarse aggregate with a mixture of plastic and granite pieces coarse aggregate, which can give us the same or more strength and has the same amount of workability as compared to nominal concrete. In this paper, we have worked on the M20 grade of concrete moulds/blocks. Tests were carried out on fine aggregates, high density waste plastics, coarse aggregates, cement, and plastic-granite coarse aggregate to determine their physical properties. Cubes of sizes 0.15 m × 0.15 m × 0.15 m were casted and were tested for 7-days & 28-days of compressive strength.