Size Effects of Finite Element Model for Three-Dimensional Microstructural Modeling of Asphalt Mixture

Kuanghuai Wu,Qingzi Deng,Xu Cai,Wenke Huang,Naiming Deng

doi:10.1155/2019/1754567

Kuanghuai Wu, Qingzi Deng + Show 3 more

Open Access

https://doi.org/10.1155/2019/1754567

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Abstract

Asphalt mixture is a particulate composite material consisting of aggregate, mastic, and air voids. The computed tomography (CT) image-based finite element approach is used as an effective method to simulate micromechanical response of asphalt mixture. For finite element analysis, the accuracy of the finite results is determined by the size of the finite element. In this paper, a voxel-based three-dimensional (3D) digital reconstruction model of asphalt mixture with the CT images after being processed was proposed. In this 3D model, the aggregate phase was considered as elastic materials while the asphalt mastic phase was considered as linear viscoelastic material. Four micromechanical digital models were generated, whose voxel sizes were 0.5 mm, 0.67 mm, 1.0 mm, and 2.0 mm, respectively. The four digital models were used to conduct uniaxial creep test for predicting creep stiffness modulus to investigate the effect of voxel size. Simulation results showed that the voxel sizes had a significant effect on creep stiffness modulus. For the creep simulation test, the most appropriate voxel size whose creep stiffness modulus changes within 2.5% is 1.0 mm with regard to time steps, computational time, aggregate, and mastic shape representations.

Highlights

Objective. e objective of this study is to investigate size effects of finite element model for three-dimensional microstructural modeling of asphalt mixture
The dead load was imposed to the reference node, and the rigid body distributed the concentrated load on the top surface of the asphalt mixture digital model. e viscoelastic analysis step was used in this paper. e total analysis step time was 10 and the incremental step time was 0.1
Summary and Conclusions. e size effect of finite elements in the three-dimensional microstructural numerical model of asphalt mixture was studied in this paper

Summary

Introduction

E traditional trial and error approach in industrial practice has focused on empirical experiments that develop correlations between the macro phenomena and the material characteristics This traditional approach does not provide information that can be used to explain why certain mixtures perform better than others. This approach is cost intensive, high-resource consuming, and time consuming To overcome these shortcomings, some microstructural methods and numerical techniques are developed to gain insight into the performance of asphalt mixture. E objective of this study is to investigate size effects of finite element model for three-dimensional microstructural modeling of asphalt mixture. The image-based numerical specimens are applied to conduct the creep simulations in order to investigate size effects of finite elements on creep stiffness

Three-Dimensional Microstructural Reconstruction

Material Parameters

Background

Numerical Simulation and Result Analysis

Findings

Conclusions and Future Work