• 2026-05-08
• A.T. Akinbuluma, S.T. Oyewo
• Volume 2, Issue 1

Abstract

Lateritic soils common in tropical regions, are known for their high iron content and complex microstructure, both of which significantly affect their hydraulic behavior. Despite extensive studies on laterite soil properties, the specific impact of ferric oxide on permeability is mostly underexplored. This study investigates the geotechnical influence of ferric oxide (Fe₂O₃) accumulation on the permeability of lateritic soils across five locations in Lagos state, Nigeria. X-Ray Fluorescence (XRF), permeability tests, Atterberg limits, porosity calculations, and microstructural SEM analyses were conducted to assess the correlation between Fe₂O₃ content and soil hydraulic behavior. Results reveal a strong inverse correlation (r = -0.96, p < 0.05) between Fe₂O₃ concentration and permeability. Soils with high ferric oxide levels (≥17%) particularly from Badagry, Epe, and Ajah showed drastically reduced permeability (k = 10⁻⁷ to 10⁻⁸ m/s), high plasticity indices (>20%), and compact microstructures with poorly connected pores. Conversely, Ikeja and Ikorodu soils with lower Fe₂O₃ ( 10⁻⁶ m/s), lower plasticity, and open-textured pore structures. A linear regression model (R² = 0.943) confirmed Fe₂O₃ as a key predictor of permeability. The study concludes that ferric oxide plays a critical role in reducing permeability in lateritic soils through both physical blockage and chemical binding mechanisms. These findings are vital for geotechnical design in tropical regions. The study therefore recommends that lateritic soils with high degree of Fe₂O₃ be avoided or modified in sub-base or drainage-sensitive applications and Soil stabilization techniques be considered where permeability needs improvement.