Correlation between mineralogical, chemical and geotechnical properties of lateritic soils of Ngaoundal: implication for road construction

This work aims to highlight the relationships between the petrological and geotechnical parameters of the lateritic soils of Ngaoundal and to make it easier to prospect for lateritic deposit and predict their behaviour on construction sites. The results of the mineralogical and geotechnical analyses of the soils obtained were subjected to classic statistical treatments and a principal component factor analysis. Principal component analysis reveals several correlations. Strong negative correlations exist between SiO2 and Fe2O3 (r = − 0.98), and positive correlations between Fe2O3 and Al2O3 (r = 0.80). Mineralogically several strong correlations exist between the different minerals. Geotechnically, there are positive correlations between the liquidity limit and the plasticity index (r = 0.98) and between the liquidity limit and the maximum dry density (r = − 0.89). The SiO2 content shows good positive correlations with the quartz content (r = 0.97) and negative correlations with kaolinite (r = − 0.98). The TiO2 content has a good negative correlation with swelling (r = − 0.93). The grain density is positively correlated with the goethite content (r = 0.71). The maximum dry density shows a good correlation with goethite (r = 0.71). For the simple regression, three relationships with good correlation coefficients were obtained. The analysis of the dendrograms shows that at the chemical, mineralogical and geotechnical levels, there are similarities between the soils samples studied. The studied lateritic soils have good geotechnical characteristics and are suitable for use as foundations and base courses in road construction for all types of traffic. These results have an impact on laterite prospecting in the sense that they make it possible, in certain cases, to guide it.