MUN , SUNGHO . Nonlinear Finite Element Analysis of Pavements and Its Application

MUN, SUNGHO. Nonlinear Finite Element Analysis of Pavements and Its Application to Performance Evaluation. (Under the direction of Dr. Y. Richard Kim and Dr. Murthy N. Guddati.) This research documents the findings from the study of failure mechanisms of fatigue cracking in asphalt pavements using the finite element program that employs the viscoelastic continuum damage model for asphalt layer and a nonlinear elastic model for unbound layers. Both bottom-up and top-down cracks are investigated by taking several important variables into account, such as asphalt layer thickness, layer stiffnesses, pressure distribution under loading, and load levels applied on the pavement surface. The crack initiations in different pavement structures under different loading conditions are studied by monitoring a damage contour. The developed finite element code, called VECD-FEP++, employs the viscoelastic continuum damage model as the constitutive model of asphalt concrete and the universal model (or so-called Uzan-Witczak resilient modulus model) for unbound materials. The finite element analysis of various pavementload combinations showed significantly different failure mechanisms. Details on the VECD-FEP++ and the findings are given in the following chapters.