Mechanical characterization of an alternative laterite gravel used as pavement material

Abstract

Laterite gravels have been successfully adopted as pavement materials in the field. Despite that, they are often rejected in material selection processes because of its base on traditional gradation and consistency limits requirements. To allow a deeper evaluation of such material found abundantly in tropical countries, along to characterizing traditional parameters, repeated load triaxial tests were performed in a Laterite Gravel from Acre/Brazil to evaluate its elastic and plastic behavior through Resilient Modulus (RM) and Permanent Deformation (PD), respectively. In addition, a simulation was conducted in the MeDiNa software, based on the test results considering stress states that are usually applied in pavement layers. The material showed RM values higher than 500 MPa, which was considered high compared to materials such as Quartz and Granite. It was also observed low permanent deformation (below 1 mm for higher tensions applied) and accommodation of displacement (shakedown) for most specimens. The simulation results showed low rutting prediction for the Laterite Gravel applied in highway pavement layers. Thus, the results indicated that the lateritic gravel can be adopted in the composition of base or subbase layers of flexible pavements, even though some limits of the parameters specified by traditional specifications were violated, as expected. In addition, we also highlight the need for adoption of new material selection strategies that are based on key mechanical characteristics to avoid discarding potentially well performing materials.

Keywords
Flexible pavements; Mechanical behavior; Permanent deformation; Resilient modulus; Shakedown theory