Laboratory-to-field geotechnical suitability assessment of granular lateritic materials-crushed rock aggregate mixture for tropical pavements

Granular lateritic materials (GLM), widely used in tropical regions for their availability and low cost, often exhibit high variability and inadequate bearing capacity to satisfy pavement design requirements. Nevertheless, their local abundance makes them a cost-effective option when properly improved. This study evaluates the suitability and structural performance of a granular lateritic materials–crushed rock aggregates mixture for pavement layers through laboratory characterization and in-situ measurements. A 75/25 mixture of GLM and crushed rock aggregates (CRA) was formulated and tested. Laboratory investigations included compaction, California Bearing Ratio (CBR), Micro-Deval, and Los Angeles abrasion (LAA) tests, while field performance was assessed using in-situ compaction control and deflection measurements. Results show that GLM are suitable for subbase applications (MDD = 2.094 g/cm³; CBR = 36%), whereas CRA meets base layer requirements with high mechanical resistance (Micro-Deval < 15; LAA < 45; CBR ≥ 60%). The combined material exhibited good homogeneity after nine mixing cycles. Field implementation achieved compaction degrees ≥ 98 ± 2% and low characteristic deflection (D90 ≈ 80/100 mm), indicating adequate stiffness under traffic loading. Differences between laboratory and field values remained limited (ΔMDD ≈ 0.043 g/cm³; ΔCBR ≈ 8%), confirming the reliability of the proposed mixture. These findings demonstrate that a properly designed GLM–CRA mixture provides a durable, cost-effective, and sustainable alternative for tropical pavements, promoting the efficient use of locally available materials.