Numerical method applied to the nondestructive characterization of the cracks in the roadways

Abstract This article proposes numerical simulations for the thermal nondestructive characterization. It relates to the thermal nondestructive study of defects of cracks type in the roadways. The model used is a semi-rigid roadway containing cracks of various positions and sizes. The thermal behavior of the roadway, according to geometrical and thermophysical parameters of the defect, is analyzed. A constant density of heat flow is applied to the higher face of the wearing layer of the roadway, the face of lower part of the base layer being maintained at a constant temperature. The influence of the various geometrical parameters of the defect (size, thickness and position) is studied and the thermographical image of the face of entry is simulated then analyzed. The numerical method adopted for the resolution of this problem is that of the finite elements. 1. Introduction The evaluation of the state of the roadways is an essential sector to identify the afflicted places, and for the planning and the assignment of the budgets of maintenance. The vehicular traffic worsens the cracks and propagates them towards surface, which leads to the deterioration of the external and fundamental layers [1]. For this reason, the first identification of the weak zones and cracks make it possible to departments of transport to develop remedies to attenuate the negative impacts and to lengthen the lifespan of the roadways. The ideal scenario in the evaluation of the defects is based on nondestructive approaches to prevent to obstruct the vehicular traffic. In this article, we will draw up a numerical study of the response of a semi-rigid roadway, containing defects of the cracks type, with a thermal wave and the influence of such defects on the thermographical image simulated on the road surface. Indeed, When a material is thermically requested, (e.g. reheating in a natural way by the sun), diffuse heat in material and the presence of a defect within the material (e.g. a crack) generally modify the heat flux through the structure taking into account the difference between the thermophysical parameters of material and those of the defect. It follows from there the appearance of a more or less hot zone on the surface compared to close material deprived of anomaly [2, 3]. To be able to detect the presence of an anomaly in the structure, the change which flow undergoes must be sufficient so that the contrast of temperature, between the healthy zones and the problematic ones, is significant and detectable thereafter.