Effects of pozzolana addition and geogrid reinforcement of lateritic clays in the sub-Saharan zone (West Cameroon): Implications for road construction

The effects of pozzolana addition and geogrid reinforcement of lateritic clays for road construction in the sub-Saharan zone (west Cameroon) were evaluated. Geotechnical studies were carried out on the sampled materials determining their physical and compaction characteristics, compressive strength and elasticity modulus. The studied lateritic clays are very thick red materials (2.0–3.5 m), thinner (63–68%), more plastic (35–36%) and of low bearing capacity (CBR = 10–13%) as compared to pozzolanas (CBR = 36%). These lateritic clays can be used as subgrade, whereas pozzolanas can be used as sub-base, despite their low maximum dry density (1.486–1.523 g/cm 3 ). The pozzolana addition (20–40%) to these lateritic clays results in a decrease in plasticity (35–20%) and an increase in bearing capacity (12–29%), uniaxial compressive strength (0.136–0.296 MPa) and Young's modulus (78.50–280.70 MPa). Pozzolana-improved materials (LCP) can be used in subgrade and sub-base courses for T1 and T2 traffics. The LCP geogrid reinforcement leads to an increase in bearing capacity (17–50%), compressive strength (0.177–0.683 MPa) and Young's modulus (139.7–607.3 MPa). This increase minimises the deformation of these materials once implemented. Geogrid-reinforced LCP mixes (LCPG) can be used in sub-base and base courses for T1 to T3 traffic. The economic analysis confirms that LCPG materials are viable in an unfavourable financial context. It is less expensive to use LCPG in the study area than natural materials such as lateritic gravels and rock-crushed stone.