Valorization of Sugarcane Bagasse Ash and Steel Slag in Concrete: Experimental Evaluation of Mix Performance and Structural Properties

This study investigates the use of sugarcane bagasse ash (SCBA) and steel slag (SS) as partial replacements for cement and natural river sand in concrete, with the objective of identifying replacement levels that maintain structural performance while reducing the consumption of conventional materials. An experimental program was conducted to evaluate the unit weight, compressive strength, and splitting tensile strength of concrete containing SCBA and SS in individual and combined replacement systems. The results showed that the incorporation of SCBA reduced concrete density, whereas SS increased unit weight due to its higher specific gravity. At 28 days, compressive strength ranged from 13.09 to 38.10 MPa, while splitting tensile strength varied between 1.81 and 4.74 MPa, depending on the replacement level and combination of materials. Among the investigated mixtures, the concrete containing 15% SCBA and 50% SS exhibited the most favourable overall performance, achieving the target compressive strength of 25 MPa required for structural applications while maintaining acceptable tensile strength. In contrast, higher replacement levels resulted in strength reductions attributed to cement dilution, increased porosity, and the delayed pozzolanic reactivity of SCBA. Overall, the findings demonstrate that appropriately proportioned SCBA and SS can be successfully incorporated into concrete without compromising structural performance. The optimal mixture provides an effective balance between mechanical performance and the utilization of alternative raw materials, highlighting the potential of these industrial by-products to support more sustainable concrete production.