Evaluation of the Effect of Material Properties on the Dynamic Response of Flexible Pavement under FWD Loading

Document Type : Original Article

Authors

Farzaneh Ghadyani Nezhad Razaki ¹

Mohammadreza Khanmohammadi ²

Mahdi Shojaei ¹

¹ Department of Civil Engineering, Isfahan University of Technology, Isfahan, Iran

² Department of Civil Engineering, Isfahan University of Technology

10.22067/jfcei.2025.95401.1375

Abstract

A precise evaluation of pavement structural performance under the dynamic loading of the Falling Weight Deflectometer (FWD) requires simultaneous consideration of complex material properties and loading conditions—an issue often treated only partially in previous studies. In this research, a finite element model was developed to dynamically simulate the response of flexible pavement subjected to FWD loading. The model was applied in a case study of a pavement in Khuzestan Province, and after validation, the effects of dynamic analysis, viscoelastic asphalt properties, anisotropic and nonlinear behavior of unbound materials, and the presence of bedrock were investigated. To include nonlinear and anisotropic characteristics, a FORTRAN subroutine was coded and integrated into the model. Results showed that dynamic analysis could increase pavement deflection by up to 44%, especially at high temperatures. Considering viscoelastic properties increased deflection values by up to 27% compared to the elastic condition. Transverse isotropy caused up to a 15% rise in pavement deflection and more than a 50% increase in critical responses, leading to shorter fatigue life and greater rutting depth. Moreover, the nonlinear modulus, particularly in the base layer, significantly affected critical responses. The presence of bedrock at depths shallower than 4 meters also influenced the dynamic response, mainly at points distant from the load center. This modeling framework can serve as a basis for improving the analysis and interpretation of pavement behavior under FWD loading.

Keywords

Falling Weight Deflectometer (FWD)

dynamic analysis of flexible pavement

viscoelasticity

non-linear analysis

transversely isotropic

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