Fermented Banana Stem Extract as a Sustainable Water-Reducing Admixture in Concrete

This study explores the utilization of Fermented Banana Stem (FBS) extract as a sustainable bio-based water-reducing admixture in concrete. The FBS extract was prepared by collecting fresh banana stems, cleaning, chopping, and mixing them with water in a 1:1 ratio by weight. The mixture was then fermented naturally at room temperature for seven days, followed by filtration to obtain brownish, mildly fermented liquid rich in organic compounds. Physical characterization revealed a viscous texture and earthy odor, while chemical analysis confirmed the presence of phenolic compounds, polysaccharides, and organic acids, which are known to enhance workability, strength, and durability in cementitious systems.In the experimental phase, FBS extract was used to partially replace mixing water at 0%, 5%, 10%, 15%, 20%, and 25% proportions for an M20 grade Concrete. Standard tests were conducted to evaluate the workability (slump test), compressive strength (after 7 and 28 days of curing), and durability (water absorption test) of the prepared concrete mixes. Results indicated that FBS addition significantly improved workability, The slump increased from 75 mm to 112 mm. The maximum compressive strength of 30.25 MPa was observed at 15% replacement, attributed to improved particle dispersion and enhanced hydration due to the organic compounds present in the extract. Beyond 20% replacement, a slight reduction in strength was recorded, suggesting an oversaturation effect. Moreover, water absorption decreased consistently with increasing FBS content, confirming improved pore structure and reduced permeability.In conclusion, Fermented Banana Stem extract can serve as an effective and eco-friendly admixture in concrete production. An optimum dosage of 15% replacement of mixing water enhances workability, compressive strength, and durability, promoting sustainable and green construction practices.