Exploring okra-based biopolymer as a green binder for stabilizing clayey soil

Abstract

The requirement for sustainable soil stabilization techniques has increased interest in natural and eco-friendly alternatives to conventional soil stabilizers. This study presents the first attempt to utilize okra mucilage solution—a biopolymer derived from Abelmoschus esculentus—for the stabilization of clayey soil. The okra mucilage solution is a safe and environmentally friendly material. Its mucilage, a viscous material high in organic polysaccharides, offers potential for soil stability. The okra mucilage solutions were prepared in three concentrations by weight-to-volume ratios of 1:30 (1 g okra: 30 ml water), 1:20 (1 g okra: 20 ml water), and 1:10 (1 g okra: 10 ml water), respectively and applied to clayey soil to assess its consistency limits, compaction, and unconfined compressive strength (UCS) at different curing periods. The UCS of untreated soil increased from 207.82 kPa to 293.93 kPa, 338.49 kPa, and 380.22 kPa for the 1:30, 1:20, and 1:10 concentrations, respectively, after 28 days of curing. The maximum value of UCS was found at a 90-day curing period for a 1:10 concentration. The treatment further improved the consistency limits and compaction characteristics. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses provided microscopic insights, supplementing the lab testing and helping to estimate the internal mechanism. Analysis of variance (ANOVA) on UCS data yielded significant results, further confirming the significance of the results. Okra mucilage shows strong potential as a sustainable, readily available alternative to conventional soil stabilizers.