Experimental Investigation on Steel Fiber-reinforced Slag Aggregate Concrete: A Path Towards Green Construction

Introduction/Objective The depletion of natural aggregates and accumulation of steel slag waste pose environmental challenges. However, there is limited research on the combined effect of steel fiber and slag aggregate in concrete. This study evaluates the fresh, mechanical, durability, and microstructural properties of Steel Fiber-Reinforced Slag Aggregate Concrete (SFRSAC) to identify the optimum fiber content and slag replacement level for durable, sustainable concrete. Methods Twenty concrete mixes were prepared with varying amounts of steel fiber and slag aggregate replacing coarse aggregate. Fresh properties were assessed via the slump test, and hardened properties via compressive, flexural, and split tensile strength, ultrasonic pulse velocity, abrasion resistance, apparent density, permeable voids, water permeability, acid attack, and chloride penetration. The microstructure was investigated using detailed SEM analysis. Results Steel fiber improved mechanical performance, with the optimum mix achieving a compressive strength of 59 MPa, approximately 27% higher than conventional concrete. Slag aggregate enhanced acid and chloride resistance, and SEM confirmed a denser microstructure with improved interfacial bonding and reduced microcracking. Slag utilization reduced natural resource consumption and material cost. Discussion The interaction between steel fiber and slag aggregate improved mechanical properties, durability, and microstructural integrity, confirming that combining fiber reinforcement with industrial waste aggregate is an effective route to durable, high-performance, sustainable concrete. Conclusion Combined utilization of steel fiber and slag aggregate produces sustainable, high-performance concrete, with 3% steel fiber and 50% slag aggregate replacement giving the optimum overall performance. This mixture is recommended for structural and infrastructure applications requiring enhanced strength, durability, and sustainability.