Análise de fatores intervenientes na propagação de trincas de cima para baixo em pavimentos asfálticos a partir do software ABAQUS

Abstract

Top-down cracking is a failure mechanism in flexible pavements, considered to be a minor problem in Brazilian pavements, mainly for its rare frequency, possible to many factors such as the low-temperature variation at the surface and most usage of thin asphalt layers in the country. However, the oncoming mechanistic pavement design can result in thicker asphalt layers, as usual in most countries of the northern hemisphere, mostly by considering subgrade material singularities and fatigue cracking predictions. This paper's main objective is to investigate the possible major causes for top-down cracking, and posterior analysis of them with a FE model design and structural response test. Abaqus is a mechanical simulation software that provides stress, strain, and deflection results, in three-dimensional graphics, for structural analysis by finite elements model. The contact pressure distribution was simulated by the usage of experimental values in previous works, which have been discovered it’s a non-equal distribution of pressure at the contact area between the tire and surface layer. It is known that tire pressure distribution can be by two main forms: low tire pressure/high load makes the “m” distribution, defined by its higher pressure at tire lateral edges, and high pressure/lower loads results in the “n” distribution, with higher pressure on the center of the contact area. The main results have been analyzed and focused on the main top-down cracking mechanisms, as seen in the literature review. Higher transverse shear stresses are localized right below tire edges and can be a major cause of surface occurrence, because of its low distribution for the base layer. The inverse can be seen for longitudinal shear stresses, which indicates a more fatigue-cracking connection for them.