Fermented banana stem extract as a workability-enhancing bio-based admixture for concrete

This study investigates the use of fermented banana stem (FBS) extract as a sustainable bio-based admixture in M-20 concrete. The novelty of this work lies in utilizing fermentation-derived banana stem extract, which contains organic compounds that may influence cement hydration and particle dispersion. The FBS extract was prepared through a controlled seven-day fermentation process and characterized in terms of basic physical properties, including pH, specific gravity, viscosity, and total dissolved solids. It was then incorporated as a bio-based admixture through partial replacement of mixing water at levels of 0%, 5%, 10%, 15%, 20%, and 25%. The results indicate that workability increased significantly, with slump values rising from 75 mm (control) to 112 mm at 25% incorporation. Compressive strength improved up to 30.25 MPa at 15% replacement, followed by a slight reduction at higher dosages. Water absorption decreased from 0.60% to 0.38% with increasing FBS content, indicating reduced water uptake. The measured water absorption values are lower than typical ranges reported in the literature; therefore, they are presented for comparative evaluation within this study. The findings suggest that moderate incorporation of FBS extract (≈ 15%) can enhance concrete performance. However, the study is limited by the absence of detailed chemical characterization and statistical analysis, and further investigation is required to validate the proposed mechanisms.