Abstract: This study investigates the geochemical and geotechnical properties of soils from Uwelu, Benin City, Nigeria (6.3861°N, 5.5827°E, 107 m altitude), to assess their engineering relevance. Samples from two sites underwent tests including specific gravity, sieve analysis, Atterberg limits, compaction, and California Bearing Ratio (CBR), following ASTM and AASHTO standards. X-ray fluorescence (XRF) was used to determine the presence of major oxides and trace elements. The soils, classified as A-2-4 and A-2-6 by AASHTO, had specific gravities of 2.55 and 2.54. The optimum moisture content was 10%, with Maximum Dry Densities (MDD) of 2.01 and 2.06 g/cm³. CBR results showed higher strength in unsoaked samples (20.11%, 6.38%) than soaked ones (9.69%, 3.24%). SiO₂ dominated the geochemistry (57.33%, 48.36%), with notable Al₂O₃ and Fe₂O₃. The findings emphasize the value of integrating geochemical and geotechnical analyses in construction.
Keywords: XRF, geochemical characterisation, geotechnical test, Atterberg’s limit, CBR
