Sustainable Soil Stabilization: Enhancing Expansive Soil with Natural Luffa Fiber

Abstract The swelling behavior of expansive soils presents significant challenges in geotechnical engineering, primarily due to volume changes induced by moisture fluctuations. Among various stabilization techniques, the use of natural fibers has emerged as a cost-effective and environmentally friendly alternative to conventional chemical stabilizers. Luffa fibers, in particular, offer promising potential due to their low cost and sustainable nature. This study investigates the effectiveness of luffa fibers as a stabilizing agent for expansive soils and assesses their suitability for practical soil remediation applications. Laboratory tests were conducted on expansive soil samples collected from the Hammam N’Bail region in Guelma. The study examined the effects of varying luffa fiber contents (0.5%, 1%, 1.5%, and 2% by dry weight of soil) on key geotechnical properties, including Atterberg limits, free swell, swelling pressure, blue methylene value, pH, and compaction characteristics, using the Standard Proctor test. The results demonstrate that incorporating luffa fibers improves the engineering properties of expansive soil by reducing plasticity and swelling, while enhancing cohesion and compaction. Optimal performance was observed at fiber contents between 1.0% and 1.5%, which provided the best balance of increased shear strength, reduced plasticity index, improved internal friction, and minimized swelling. These findings support the potential use of luffa fibers as a sustainable, natural stabilizer for expansive soils.