Assessment of Geotechnical Properties of Lateritic Gravels from South-Cameroon Road Network

Abstract

The southern road network covers the eastern, central and southern administrative regions; its linear network of national and provincial roads is about 5 620 km. It was the subject of a survey for the identification of lateritic quarries. To this effect, 144 sites have been discovered. The collected lateritic gravels were subjected to identification analyzes (Granulometry, Atterberg Limits, densimetry, water content) and geotechnical characterization tests (Proctor Modified, CBR at 95% OPM). The obtained results show that the grain size has a great percentage of gravels (>60%) followed by sand. Stones silt and clay particles are poorly represented. The samples show a high plasticity in conformity with Casagrande’s plasticity diagram. The density values of the solid particles ( γ s ) are quite stable in the studied area and vary between 26 and 29 KN/m3 for a natural water content comprised between 10% and 20%. The modified proctor test gives an optimal water value (Wop %) comprised between 8% and 12%. Dry density values ( γ d ) varied between 18 and 30 KN/m3. The bearing capacity of the materials is good (30 < CBR < 90). These results permit the recommendation of the studied materials as foundation layers of roads for traffic classes between T1-T4.