Contribuições para um método mecanístico-empírico de dimensionamento de pavimentos asfálticos: influência da temperatura e da velocidade de tráfego na previsão de área trincada

Abstract

The recent proposed asphalt pavement design method brings significant improvement to Brazilian roadway infrastructure. Pavement layers structural analysis and monitoring of test sections, in terms of cracked area, allow the use of Transfer Functions (TF) to predict cracking evolution under a mechanistic-empirical method. The Resilient Modulus (RM) for stiffness and Diametral Indirect Tensile (DT) test for fatigue characterization are intended to be used for structural analysis inputs and fatigue simulation, respectively, on the method currently considered. Although the tests are state of practice in many laboratories, they do not incorporate viscoelastic parameters neither in stiffness nor in fatigue simulation. In addition, criticisms are found in the literature, particularly to the DT test, and they provide a greater understanding for more appropriate characterization of Hot Mix Asphalt (HMA) in Brazil. This research carries out analysis of predicted cracked area (%CA) using a viscoelastic test system characterization, such as Dynamic Modulus (|E*|) for stiffness and Uniaxial Direct Tension-compression (DTC) test for fatigue. For fatigue modeling, the S-VECD (Simplified Viscoelastic Continuum Damage) approach is used, which is yet largely disseminated in Brazil. In order to broaden the understanding of appropriate viscoelastic characterization for pavement design, sensitivity analysis are performed upon %CA with respect to the following variables: (i) traffic, with respect to intensity and speed; (ii) climate, with respect to air temperature; (iii) S-VECD modeling parameters for damage. To achieve such desired analysis, a new TF is calibrated for 23 monitored sections under Petrobras’s Asphalt Technology Network, in CAP3D-D software, developed at Federal University of Ceará (UFC). The results indicate particular relevance of air temperature in predicted %CA, as well as significant relevance of traffic intensity. The sensitivity tests of S-VECD parameters allowed a deeper understanding of the DTC modeling under continuum damage theories, identifying the most sensible parameters, as Δ in GR(Nf), besides major discussions regarding the ß parameter. This parameter, specifically, originated relevant propositions for future researches regarding simulations and structural analysis.