Analysis of the unsaturated behaviour of compacted lateritic fine-grained tropical soils for use in transport infrastructure

This article evaluates the unsaturated behaviour of fine-grained tropical soils for application in transport infrastructure. An extensive experimental campaign was conducted covering physical, chemical, mineralogical and mechanical tests. Simulations of a pavement structure were carried out applying the new Brazilian pavement design method (MeDiNa). The results showed highly weathered soils, with classification ranging from A-4 to A-7-6 (TRB), SC, SM, ML and CL (USCS), but of the same class MCT (LA’ – lateritic sandy soils), bimodal SWCC and excellent resilient modulus (394–680 MPa). The compaction directly influenced its unsaturated behaviour. The soils were proved to be suitable for use in the pavement with high traffic, thus enabiling the exploitation of the local materials and reducing costs with transport and acquiring scarce granular materials. Polynomial and linear regression equations were proposed to predict the MR as a function of confining and deviation stresses acting in the subgrade and sub-base layers.