Developing high-performance low-carbon concrete using ground coal bottom ash and coconut coir fibre

This study addresses the need for eco-friendly concrete by incorporating agro-industrial waste, ground coal bottom ash (GCBA) and coconut coir fibre (CF), as partial replacements for Ordinary Portland Cement. A total of 150 samples were tested using Scanning Electron Microscopy (SEM), Fourier-transform infrared (FTIR), X-ray Fluorescence (XRF) and mechanical methods. Optimal results were achieved with 4.31% CF, 0.4% superplasticizer, and 33.61% GCBA, improving compressive and tensile strength by 44.54% and 48.12%, respectively, with enhanced flexural performance. The addition of CF reduced cracking and improved durability and GCBA enhanced long-term performance through improved particle packing and pozzolanic reactions. The GCBA-CF mixtures also lowered embodied carbon by 194 kg CO₂/m³ and energy by 970 MJ/m³, achieving higher eco-efficiency than traditional concrete. This research supports the development of sustainable, high-performance concrete aligned with circular economy and sustainability goals.