INVESTIGATION INTO THE PERFORMANCE OF CONCRETE WITH BIOCHAR PARTIALLY REPLACING CEMENT

The environmental impact of conventional concrete, particularly the high carbon emissions associated with Portland cement production, has necessitated the development of sustainable alternative construction materials. This study investigates the optimization of biochar-enhanced concrete as a partial replacement for cement, with the aim of improving mechanical performance while reducing environmental footprint. Biochar was produced from locally sourced agricultural biomass through slow pyrolysis at 500°C and incorporated into concrete mixes at replacement levels of 0%, 2.5%, 5%, 7.5%, and 10% by weight of cement. Experimental investigations were conducted to evaluate the fresh and hardened properties of the concrete, including workability, compressive strength, and split tensile strength at 7 and 28 days. Results indicated that increasing biochar content led to a gradual reduction in workability due to its high water absorption capacity. However, concrete mixes containing 2.5% to 5% biochar exhibited improved mechanical performance compared to the control mix. The optimal mix, containing 5% biochar, achieved a 28-day compressive strength of 37.5 MPa, representing a significant improvement over conventional concrete. Beyond this optimal dosage, higher biochar contents resulted in reduced strength due to increased porosity and dilution of the cementitious matrix. The findings demonstrate that biochar can be effectively utilized as a sustainable cement replacement when properly optimized, offering benefits such as enhanced strength, internal curing, waste valorization, and carbon sequestration. This study concludes that biochar-enhanced concrete, at low replacement levels, presents a viable and eco-friendly alternative for sustainable construction applications and recommends further research on long-term durability and field performance.