Assessing the Potential of Lateritic Clayey Soils for Road Infrastructure in Tropical Regions

Lateritic soils, characterized by complex mineralogy, a high degree of weathering, and a distinctive structure, are widely distributed in tropical regions. However, their use in pavement layers is often restricted due to conservative soil classification methods that may not fully represent their mechanical potential. This study evaluates the geotechnical behavior of a lateritic clay from a small town in São Paulo, referred to in this article as Purple Clay, with a focus on its permanent deformation (PD) and resilient modulus (RM). Repeated load triaxial tests, along with X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), were conducted to assess the soil's mechanical response and microscopic structure. The results indicated that the high concentration of iron oxides contributed to increased cohesion and mechanical strength. When compacted at intermediate Proctor energy, the Purple Clay exhibited RM values comparable to some granular materials reported in the literature, highlighting its potential for pavement applications. However, under higher stress levels, PD was up to 42% greater than that of reference materials, emphasizing the influence of loading conditions on its behavior.