Assessment of Lateritic Gravelled Materials for Use in Road Pavements in Cameroon

Early surface and structural deterioration of new pavements are becoming increasingly perceptible in Cameroon. This raises serious concerns regarding the nature, spatiotemporal evolution, and quality of materials used. Therefore, this study uses geotechnical identification, X-ray diffractometry, and statistical methods to optimize the durability of lateritic gravelled material (LGM) pavements. The CBR values within the study sites are dispersed and present low variability (coefficient of variation-CV < 15%), to high variability (CV > 35%). Three groups of LGM were distinguished at the Bamileke Plateau: firstly, LGM at the BAN site were characterized by CBR (31%). Secondly, LGM of Bamendjou 1 and Bamendjou 2 sites, characterized by CBR varying between 25 and 27%, CI between 1.3 and 1.5, gravel content among 62.7 to 64.7%, and MDD between 1.76 and 1.82 g/cm³. Thirdly the Sekakouo and Chenye sites LGM are dominated by fines with C80µm between 38 and 44%. Swelling clay minerals are absent in these materials. It results that, these materials are suitable for use as a subgrade layer for any type of traffic, and as a sub-base for low-volume traffic T1 to T3, except those at the Sekakouo and Chenye sites. Prospecting of LGM deposits should be directed towards those with high proportions of Gm, gravel content, MDD, CI, SG, and low proportions of Pm, C80µm, C400µm, Pp, ɛs and C2mm.