Contribution to the flexible pavement design guides evaluation used in tropical zone: Application to lateritic materials of Bamougoum (West, Cameroon)

The choice of any materials in the realization of sustainable road infrastructures for the well-being of populations must be made using reliable criteria. In this work, classic geotechnical characteristics and experimental Young's modulus determination of the Bamougoum lateritic materials were put together in order to raise the non-exhaustive limits of pavement design guides used in tropical zone. The results show that the Bamougoum materials are very plastic silty materials, made up mainly of the fine fraction (33.49% and 76.41%) with plasticity indices between 9.49 and 36.88. The CBR values vary from 11 to 38 and the behavior of materials is qualified as fair to poor. For compression forces of 18.30–25.45 KN, and longitudinal deformations of 0.007–0.02, Young's modulus values varies from 72 to 221 MPa with an increase percentage less than 20 from age 3–7 days. The compliance of studied materials to road pavement standards for tropical countries and technical guides indicate that they can be used in sub-base of flexible pavements of medium or low traffic. However, relying mainly on these criteria can be misrepresentative as materials characteristics vary considerably based on laboratory test procedures, climate and parent rock not considered in the different manuals. Then, the experimental Young's modulus association with the existing classical selection criteria of material to be used in road pavement could contribute to the reduction of early roads degradation in tropical countries. Moreover, the use of pre-established modulus values has a negative impact on the infrastructure durability.