Modeling of the Asphalt Concrete to Compare Uniaxial, Hollow Cylindrical, and Indirect Tensile Test

Document Type

Article

Publication Date

9-2014

Abstract

The objective of this study is to develop a micromechanical based Discrete Element Model (DEM) to simulate dynamic modulus of the asphalt concrete using Uniaxial Tensile (UT), Hollow Cylindrical Tensile (HCT), and Indirect Tensile (IDT) model. This research is used to compare DEM simulation of the UT, HCT, and IDT tests. The asphalt concrete mixture used was a 19 mm Nominal Maximum Aggregate Size (NMAS) with an asphalt content of 5.59% and air void level of 4.36% to develop UT, HCT, and IDT model. The dynamic moduli of the sand mastic and stiffness of aggregate were used as input parameters of the DEM to predict the dynamic moduli of the asphalt concrete through a virtual testing of UT, HCT, and IDT. The sand mastic had an NMAS of 1.18mm, which was used in a DEM. The three-dimensional (3D) internal microstructure of the asphalt concrete mixture (i.e., distribution of aggregate, mastic, and air voids) was obtained through the X-ray CT (Computed Tomography). From the 3D X-ray CT images, location of aggregates, mastic, and air voids were obtained using image processing. The laboratory measured dynamic moduli of asphalt concrete were used to compare predicted dynamic moduli of UT, HCT, and IDT tensile models. It was found that the UT model was able to predict the asphalt concrete modulus across a range of temperatures and loading frequencies. The HCT model was slightly lower at low and high temperatures, and the IDT model was slightly higher at a low temperature and slightly lower at high temperature. The results indicate that UT, HCT, and IDT tensile are useful models to predict dynamic moduli of asphalt concrete.

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