Contribution to resilient and permanent deformation investigation of unbound granular materials with different geological origins from Rio Grande do Sul, Brazil

This article evaluates the resilient modulus and permanent deformation of granular materials of different lithological origins widely used as a pavements base layer in south Brazil. For this, a single particle size distribution was determined for the materials that were subjected to physical, chemical, mechanical characterizations, especially resilient modulus and permanent deformation by repeated load triaxial tests. It was noticed that the denser materials had a higher resilient modulus generated by increase in the sample’s stiffness. For permanent deformation this tendency has not been maintained for all materials. Therefore, the granulation and structure of the materials can influence long-term tests. The Guimarães’ model has proven to be adequate for the sample evaluation. For the shakedown research, samples showed accommodation and creep shakedown. The samples that presented accommodation had an increase in the resilient modulus after permanent deformation, while those that presented creep increased or decreased resilient modulus according to the material origin.