Valorization of coffee cherry waste ash as a sustainable construction material

Abstract

This study explores the potential of treated coffee cherry waste (T-CCW) as a partial replacement of cement in mortar. T-CCW was characterized and incorporated into pastes and mortars at 5 %–25 % cement replacement. The main objectives were to examine the fresh and hardened properties, hydration, and environmental assessment. Results showed that the high specific surface area and porous structure of T-CCW particles increased water demand and accelerated setting times. T-CCW incorporation of up to 15 % enhanced compressive strength at all curing ages due to improved hydration and limited pozzolanic reactions. Ultrasonic pulse velocity indicated good homogeneity and compactness in T-CCW blended mortars. Microstructural analysis revealed that T-CCW enhanced cement hydration, leading to a denser matrix. Environmental analysis showed a reduced embodied carbon and cement intensity index compared to the control mix. Overall, the optimal performance was observed at 15 % T-CCW replacement, significantly improving engineering properties and environmental impact. Further, the fishbone diagram addresses various factors to optimize the use of T-CCW as a cementitious composite. These findings demonstrate the potential of T-CCW as a sustainable construction material, offering a promising pathway towards environmentally friendly and resource-efficient building practices while addressing waste management in the coffee industry. © 2024 Elsevier Ltd