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Mechanistic Pavement-Mixture Design Approaches Considering Material Viscoelasticity and Fracture: Design Framework and Comparison with Field Performance

Sayyed Amelian, University of Nebraska - Lincoln

Abstract

This study aims to establish purely mechanistic pavement-mixture design approaches where material viscoelasticity and fracture are considered to accurately predict deformation and damage behavior of flexible pavements than other conventional methods. To that end, this study applies the principles of engineering mechanics and finite element modeling (FEM) technique toward a fully mechanistic framework for analysis-design of flexible pavements. The use of FEM as a substitution of layered theory used in the Pavement ME Design method is expected to substantially improve the ability of models to capture the critical locations under traffic loads in which damages are more likely to occur. Additionally, treating asphalt mixtures as a viscoelastic material will allow including the time-, rate-, and temperature-dependent deformation and fracture of material. While modeling crack development can be done in various ways, this study used the cohesive zone approach. The FE modeling was attempted in two different approaches: single scale modeling and two-way coupled multiscale modeling. The single scale approach is to model pavement structures by assuming each layer homogeneous, but AC layer is treated as viscoelastic with cracking to better account for inelastic deformation and fracture damage. The two-way coupled multiscale approach simultaneously models both pavement structure and mixture considering heterogeneity. This way, named as the “Coupled Mechanistic Pavement and Mixture Design (C-MPMD), directly links the properties of mixture components, mixture design, and pavement structural design. In order to examine the effectiveness and the sensitivity of proposed mechanistic design approaches, the field performance data from NCAT test track, as well as the performance data from a full-scale Accelerated Pavement Testing (APT) were utilized. The modeling outputs were then compared with actual performance data to find the correlation between modeling versus field performance results. Overall, it can be concluded that mechanistic pavement analysis-design methods attempted in this study could differentiate the performance of pavement sections due to variations of design inputs. Furthermore, it is implied that C-MPMD approach can be considered a very promising design framework as it can accomplish designing of mixtures and structures at the same time within the same mechanistic framework with significantly reduced testing and computing needs.

Subject Area

Civil engineering

Recommended Citation

Amelian, Sayyed, "Mechanistic Pavement-Mixture Design Approaches Considering Material Viscoelasticity and Fracture: Design Framework and Comparison with Field Performance" (2019). ETD collection for University of Nebraska - Lincoln. AAI22592003.
https://digitalcommons.unl.edu/dissertations/AAI22592003

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