Finite element modeling of flexible pavements

Abstract

It is well-known that the analysis of flexible pavements is a difficult task, since the pavement system is multilayered and three-dimensional. To provide accurate displacements, strains and stresses, the system must consider the different characteristics of each layer. Granular layers, for example, present complex nonlinear stress-strain relationship, while the surface (asphalt) layer displays a time-dependent viscoelastic behavior. Furthermore, cracks and fatigue are some of the problems that the surface layer may present. This paper addresses techniques used in the finite element modeling of flexible pavements. Therefore, appropriate constitutive models and numerical algorithms to represent the nonlinear resilient behavior of the unbound layers and the viscoelastic characteristics of the HMA layer are thoroughly discussed. These techniques are implemented in a computer system developed using an Object-Oriented Programming (OOP) approach. Both axisymmetric and three-dimensional models are included. Several numerical examples will be analyzed in order to validate the implementation and assess the importance of the consideration of the nonlinear and time-dependent effects. The obtained results will be compared with available analytical and computational solutions.