Finite Element and Distress Models for Geosynthetic-reinforced Pavements

Abstract

A finite element (FE) response model has been developed to describe stress and strain response parameters for geosynthetic-reinforced flexible pavement systems where the geosynthetic is placed at the bottom of the unbound aggregate layer. The model contains membrane elements and an anisotropic linear-elastic material model for the geosynthetic inclusion. Elasto-plastic models are used for the asphalt concrete, base aggregate and subgrade layers. Principal response parameters extracted from the FE model include vertical strain in the top of the subgrade and bulk stress in the unbound base aggregate layer. These response parameters are used in empirical damage models for the prediction of long-term pavement performance and the definition of reinforcement benefit. Reinforcement benefit is defined in terms of an extension of service life of the pavement, a reduction in aggregate thickness for equivalent service life, or a combination of the two. The damage models are calibrated from reinforced and unreinforced pavement test sections. The model is shown to provide general descriptions of reinforcement mechanisms that are consistent with those previously observed in instrumented pavement test sections. A companion paper (S.W., Perkins and M.Q., Edens (2003) A Design Model for Geosynthetic-Reinforced Pavements, International Journal of Pavement Engineering) describes the use of the response and damage models in a parametric study from which a design model for geosynthetic-reinforced pavements is developed.

Keywords:

• Pavement
• Geosynthetic
• Reinforcement
• Numerical
• Model

Acknowledgements

The authors gratefully recognize the financial support and technical review provided by the Montana, Idaho, Kansas, Minnesota, New York, Texas, Wisconsin and Wyoming Departments of Transportation and the Western Transportation Institute at Montana State University. The technical contribution of Mr Yan Wang is gratefully recognized. Dr Muralee Muraleetharan of the University of Oklahoma and Dr Kim Mish of Lawrence Livermore National Laboratory generously provided source code and support for development of a user defined material model.