Mineralogy, geochemistry, and geotechnical characterization of lateritic and alluvial clay deposits from Batouri, East Cameroon

Physical and mechanical features of lateritic and alluvial clay mixtures from Batouri (East Cameroon) were evaluated as sustainable building materials. Collected samples were subjected to mineralogical and geochemical analyses and physical tests. Geotechnical tests (linear shrinkage, apparent porosity, bulk density, water absorption, and flexural and compressive strength) were carried out on prepared fired bricks. The analyzed samples are mainly made up of quartz, kaolinite, gibbsite, hematite, muscovite, and anatase, with SiO2, Al2O3, and Fe2O3 being the main oxides. The low proportion of fluxing oxides causes insufficient sintering during firing. These samples are sandy clays with medium plasticity, which is favorable for extrusion and manual processing. The linear shrinkage of the fired bricks is less than 5% when the firing temperature is up to 1050 °C. The low porosity values are related to the spread-out grain size distribution, which is favorable for good compaction of the final products. The flexural strength values decrease with the increase in iron and sand contents. The addition of alluvial clays increases flexural and compressive strength while decreasing water absorption. These overall features make Batouri clay mixtures suitable for dense brick production. Nine samples with water absorption lower than 20% and flexural strength greater than 6.5 MPa are suitable to produce roofing tiles.