Mechanical Characteristics of Materials for Pavement: a Case Study Laboratory and Field

Abstract

The road sector represents the largest means of transport used in Brazil, for both people and cargo. The changes in recent decades, of maximum loads and materials used in road pavements, make necessary a mechanical study of these structures to ensure its durability. The determination of the resilience modulus of these materials (required in mechanical studies) can be accomplished through laboratory tests or by retroanalise of deflectometric basins obtained in nondestructive testing of field. Thus, various computer programs can be used to calculate the stresses, deformations and displacements that occur in the structure with the application of loads. Examples of these programs are the EVERSTRESS 5.0 and EFin3D, based on Methods of Finite Layers and Methods of Finite Elements, respectively. In this work, was done a comparative study of pavement layers of resilience modules obtained in the laboratory and in the field, also establishing its implications when used in the calculations of stresses and strains for design purposes. This study was conducted to a section of existing pavement on BR-101, Northeast Brazil, built with Binder coating modified by SBS and cement-treated crushed rock base, for which it was evaluated the effect of these differences in terms of stresses, deformations and displacements calculated for each situation. It was observed significant differences in the analyses results, due to differences in resilience modules obtained in the field and laboratory (mainly for surfacing and subgrade). The structural configuration obtained by laboratory tests underestimating just half the actual structural performance of the pavement observed in the field. Further, the vertical stress calculated by the Method of Finite Layers exceeded the Method of Finite Elements.