Evaluation of Rutting and Fatigue effects of as built flexible pavement by using Finite Element Method

Abstract

This research aims to evaluate the rutting and fatigue effects of as-built flexible pavements using the Finite Element Method (FEM). Flexible pavements are commonly used in road infrastructure due to their ability to withstand dynamic loads and provide a smooth driving surface. However, over time, these pavements experience distresses such as rutting and fatigue cracking, which significantly reduce their service life and performance. The conventional methods for evaluating these distresses have limitations in terms of accuracy and capturing underlying mechanisms. Therefore, this study employs FEM to provide a detailed analysis of pavement behavior, considering complex material properties and structural configurations. The research utilizes a dataset comprising pavement sections from various locations, with detailed information on material properties, layer thicknesses, and traffic loading conditions. The FEM models are developed based on this dataset, incorporating realistic inputs to simulate the structural response of the pavements. The rutting and fatigue performance of the pavements are evaluated through analysis of stress and strain distributions, as well as the development of permanent deformations and crack propagation.Three-dimensional linear elastic plane strain problem is analyzed using finite element method using ABAQUS computer program. Wheel spacing is 13.5 in (343 mm), and tire contact pressure is 87 psi (0.6 MPa). The investigation reveals that rut depth and fatigue cracking at the bottom asphalt layer have grown due to the material's qualities, and tensile tension in that layer causes cracking at an 8% rate, despite increases in stress levels of 14% in the levelling course and 27% in the base course. Repeated traffic loads can damage existing papers by up to 80mm throughout the course of the road's useful life and ERA document conditions by 70mm which is almost 12.5% reduction. The maximum number of repetitions required to cause fatigue rises by up to 68%. The fatigue resistance decreases to 32% when only the Ethiopian Road Authority (ERA) document situations are modelled. The findings of the study reveal the influence of different factors on the rutting and fatigue behavior of as-built flexible pavements. It is observed that variations in material properties, such as stiffness and fatigue resistance, significantly affect the performance of the pavements. Additionally, the impact of traffic loading conditions, including axle loads and traffic volume, is studied to understand their contribution to pavement distresses. The research contributes to the development of accurate and reliable models for predicting the rutting and fatigue effects of as-built flexible pavements. The outcomes of this study can aid in the design and maintenance of flexible pavements, enabling the implementation of cost-effective strategies to mitigate rutting and fatigue cracking. The utilization of FEM provides a comprehensive understanding of pavement behavior, facilitating informed decision-making for road infrastructure authorities and pavement engineers.