Análise empírico-mecanística de pavimento asfáltico para verificação da influência dos módulos resilientes nos parâmetros de deformabilidade das camadas do pavimento e subleito.

Abstract

Brazilians cargo operates predominantly with road transportation, roads demand infrastructure with good performance so that it does not rupture prematurely and presents projects estimated durability. Pavement layers must work together so that there is stiffness compatibility between its materials, avoiding high gradients of resilience modules (MR) between layers. Thus, structure, characteristics of the materials and the stiffness of each layer are important parameters and directly relate to the evaluation compatibility of deformations and stresses in the pavement. Which should minimize the accumulation of rutting deformation, and prevent that repetition of loads does not cause excessive cracking of the surface by premature fatigue, considering the performance of the pavement in the short, medium and long term. The main objective of this research was to evaluate the influence of resilience modules of all layers on the mechanical properties of a homogeneous segment of federal highway BR-230, through probabilistic analysis with the FOSM Method, sought to identify the critical layers that affected the design of the structures reinforcement. This study was performed through structural evaluation of the pavement, using data from deflectometric surveys carried out with the Falling Weight Deflectometer (FWD) equipment, which made it possible to do retroanalysis of the pavement by the BAKFAA program and the analysis of displacements, stresses and deformations with the ELSYM5 program. Which is necessary for compatibility analysis of the structure and for probabilistic analysis of the pavement carried out with the FOSM Method (First Order Second Moment). This study identified that programs BAKFAA and ELSYM5 programs showed a good correlation between the theoretical calculated basins, which indicated compatibility in the multiple elastic layer analysis implemented in these programs, with similar structural discovered values. The probabilistic analysis with the FOSM method allowed to infer the base layer as the most critical. Resilience modules of the surface and base layers as the most main module for the variance of the stress difference and tensile strain in the surface, and consequently in the fatigue lifespan of this layer. This study identified the natural subgrades resilience module as the most main module for compression strain and vertical stresses at the top of the subgrade, followed by the resilience module of subbase and surface coarses. These data indicate the need for a better dimensioning of base reinforcement, greater control of execution and compaction in order to obtain suitable stiffness modules for the project and guarantee the layer homogeneity, decreasing thus the areas with high concentration of tension in relation to what was defined in the executive project.