Geotechnical, mechanical and geological characterization of lateritic gravels of Boumpial (Cameroon) used in road construction

The present study deals with a geological, mechanical and geotechnical characterization of lateritic gravels developed on gneiss in the Boumpial region (East Cameroon). The raw materials description was done during the fieldwork. The collected samples were subjected to mechanical and geotechnical tests. The rock sample powder and lateritic gravels mineralogy were determined using optical microscopy and X-rays diffraction on the total fractions and the fine ones. The overall chemical compositions of major elements of lateritic gravels were determined by the use of X-fluorescence and titrimetry. The results obtained show that lateritic gravels of East Cameroon present: fines (18 wt.%), plasticity index (21%), CBR (72%), compressive strength (1.27 Mpa) and tensile strength of 0.08Mpa. The X-ray diffraction and the chemical analysis revealed 34 wt.% kaolinite, 24 wt.% of hematite, 13 wt.% of goethite, 11 wt.% of quartz, 10 wt.% of gibbsite and 1 wt.% of anatase. The silica/sesquioxides ratio (1.04) showed that the lateritic gravels is suitable for the sub-base course in road construction. By mixing 20 wt.% of the 5/20 rock fragment fraction (with LA< 60) and 80 wt.% of lateritic gravels (CBR = 92 %), the studied material can be employed for constructing foundations.Keywords: Lateritic gravels; Geotechnical and mechanical tests; Mineralogical and chemical analyses; Road construction; Cameroo