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Keramatikerman, M. and Nikraz, H. (2016). “Flexible pavement modelling using Kenlayer.” Electronic Journal of Geotechnical Engineering , 21(7): 2467-2479. Gedafa, D. S. (2006). “Comparison of flexible pavement performance using KENLAYER and HDM-4.” Midwest Transportation Consortium, Ames, Iowa . Gupta, A., Kumar, P., and Rastogi, R. (2014). “Critical review of flexible pavement performance models.” KSCE Journal of Civil Engineering , 18(1): 142 – 148. DOI: 10.1007/s12205-014-0255-2. Hong, F., Pereira, F. M., and Prozzi, J. A. (2006). “Comparison of equivalent single axle

Abstract

In this paper, a comparison between pavement responses is performed by considering two different models for the linear viscoelastic behavior of an asphalt concrete layer. Two models, the Maxwell model and the Kelvin-Voigt model, are generalized. The former is used in ABAQUS and the latter in KENLAYER. As a preliminary step, an appropriate structural model for a flexible pavement structure is developed in ABAQUS by considering linear elastic behavior for all the layers. According to this model, when the depth of a structural model is equal to 6 meters, there is a good agreement between the ABAQUS and KENLAYER results. In this model, the thickness of the pavement is equal to 30 centimeters, and the thickness of the subgrade is equal to 5.7 meters. Then, the viscoelastic behavior is considered for the asphalt concrete layer, and the results from KENLAYER and ABAQUS are compared with each other. The results indicate that the type of viscoelastic model applied to an asphalt concrete layer has a significant effect on the prediction of pavement responses and, logically, the predicted performance of a pavement.

ABSTRACT

The evaluation of bituminous concrete mixes for their tendency to rutting has been an important research field for many years. Rutting is a major type of distress encountered in bituminous pavements. The Finite Element Method (FEM) is a numerical analysis technique to obtain various structural parameters such as stress, strain and deflection of pavement layers. The objective of this paper is to study the sensitivity of these variables in reducing the vertical surface deflections, the critical tensile strains at the bottom of the bitumen layer and the critical compressive strains on the top of subgrade using the finite element method. This study has been carried out in order to compare the performance of flexible pavement using the finite element method and KENLAYER. Vertical surface deflections in flexible pavements have always been a major concern and are used as a criterion for pavement design. It is desirable to reduce the deflections as much as possible. This paper deals with ways to reduce deflections by varying the design configuration, such as increasing the Hot Mix Asphalt (HMA) modulus, the base modulus, sub base modulus and the subgrade modulus. Another objective of the present study is to investigate the effectiveness of two different methods in reducing vertical surface deflections (wo) and the critical tensile strains in the bitumen layer (εt) or the radial strains at the bottom layer of HMA. The finite element method was adopted to evaluate the effectiveness of the two methods and the sensitivity of various factors