<b>Combined Effect of Marble Dust and Steel Fiber on the Mechanical Properties of High Strength Concretes</b> Present day construction cost is at its height with using basic materials like cement, coarse aggregates and fine aggregates. Leaving waste materials to nature specifically can bring about environmental issues. Therefore, reuse of waste materials has been emphasized. Industries produce lots of waste materials, which might be helpful in partial replacement of basic materials due to their composition and it can be proved economical. The concrete industry is always searching for supplementary material with the target of decreasing the solid waste disposal issue. As we know concrete is weak in tension so, to overcome this, steel fibers has been used. There are few reuse and recycling solutions for this industrial by product, both in experimental phase and have useful applications. These mechanical wastes are dumped in the close by areas and natural fruitfulness of the soil is ruined. The physical, mechanical and chemical properties of wastes are discussed. In this study, marble powder has replaced sand, the whole research is carried out on M60 grade concrete with partly replacing sand by 0 , 15 , 30 , 45 , and 60 of marble dust, with the addition of steel fibers at ratio 0.8 by volume so as to get greatest compressive strength, flexural strength and furthermore split tensile strength. Based upon the feasibility interpretation it is observed that replacing up to 45 marble powder and 0.8 of steel fibers in concrete is appropriate in conformance with the requirement. The compressive strength and the spilt tensile increased up to 15 replacement, after that they started decreasing. steel fibers, marble dust 384-388 Issue-4 Volume-1 KRISHAN KUMAR | SUMESH JAIN