Optimizing Concrete Compressive Strength with Coffee Bagasse Biochar: A Sustainable Approach to Waste Valorization in Construction Materials

The escalating global imperative for sustainable waste management has prompted innovative research into valorizing organic waste streams in construction materials. This study investigates coffee bagasse (BC) as a potential fine aggregate replacement in concrete, addressing both environmental challenges and material performance optimization. Through systematic analysis, the effect of coffee bagasse incorporation as fine aggregate in the compressive resistance of concrete was studied. Coffee bagasse was processed in raw and pyrolyzed states and incorporated into concrete mixtures at 5%, 10%, and 20% volume replacement levels. Differential scanning calorimetry (DSC) and comprehensive compressive strength assessments were carried out to analyze the performance and behavior of the material. The findings revealed critical insights: raw coffee bagasse lixiviation significantly impaired cement hydration, negatively affecting concrete mechanical properties, whereas pyrolysis at 349.5°C transformed BC into coffee biocarbon, yielding a remarkable 22.39% increase in concrete compressive strength. The thermal treatment emerged as a pivotal intervention for effective waste material integration, demonstrating a promising pathway for converting agricultural by-products into high-value construction materials. By bridging waste management strategies with material science innovation, this research contributes to circular economy principles, offering a sustainable approach to reducing waste and enhancing infrastructure material performance through advanced thermal processing techniques.