This project deals with the possibility of replacing the fine aggregate of concrete by sustainable materials. In this work M20 grade of concrete is taken for study and the fine aggregate is replaced by froth floated silica, a by-product of cement manufacturing plant by 20%, 40%, 60%, 80% and 100% weight of fine aggregate. The specimens are casted for testing compressive strength, split tensile strength, flexural strength and rapid chloride permeability test. The workability results shows that the replacement of fines by froth floated silica increases but in the presence of super plasticizer. The results indicate that when the fine aggregate is replaced by froth floated silica by 80% the compressive strength increased by 19.86%, split tensile strength by 16.29% and flexural strength increases by 28.14% than conventional concrete.