The base layer is important for the road pavement structural performance. This study aims to monitor the performance of various local composite materials as road construction materials. To do this, an experimental study treated the improvement of geotechnical properties of a lateritic gravel, initially nonadopted as a base layer, by using three improvement techniques: geoconcrete, soil–cement, and soil–gravel–cement to assess their stability, strength, and suitability for supporting road structures. The principle of this work is to amend natural lateritic gravel by loading crushed granite of 30 wt% and cement of various proportions from 1.0 wt% to 2.5 wt%. Nine samples of the composite were made and submitted to compaction and bearing tests. The results show that the composite cement–modified natural soils of 1.5 wt% to 2.5 wt% are suitable for the base layer of road pavement, and the best improvement of natural lateritic gravel is obtained with the crushed granite at a loading of 30 wt% and a cement loading of 1.5 wt% to 2.5 wt%. Indeed, the composite soil–gravel–cement at 1.0 wt% to 2.5 wt% gave an appropriate optimum dry density (2.205 t/m 3 ) and optimum moisture content (7.4%), which are determinants for the road’s performance. The maximum bearing capacities were obtained with a cement loading of 2.5 wt% and a crushed granite loading of 30 wt%, with CBR indexes of 410 and 548, respectively, at 95% and 98% of the optimum modified proctor. These values make the new composite material made from natural lateritic gravels/crushed granite/cement suitable for a base layer of road pavement. These findings highlight that the improvement of a composite of lateritic soil by loading both cement and crushed granite treated at an appropriate percentage offers better geotechnical performance than soil–cement and geoconcrete.
Djoko et al. (2026) studied this question.