A Dynamic Semi-Circular Bending Configuration for the Rheological Characterization of Asphalt Mixtures

Marina Cauhape Casaux,Fernando Martinez,Silvia Angelone

doi:10.32732/jcec.2020.9.3.150

Marina Cauhape Casaux, Fernando Martinez + Show 1 more

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https://doi.org/10.32732/jcec.2020.9.3.150

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Abstract

Many experimental procedures have been proposed for the determination of the rheological properties of asphalt mixtures. Among them, the indirect tensile test (ITT) has gained a lot of attention because of its relative simplicity and advantages. However, a biaxial state of stress is developed into the sample and then, the Poisson ratio must be estimated or measured for the calculations of the dynamic modulus. Looking for a testing configuration with the same simplicity and advantages, this paper proposes the Semi-Circular Bending (SCB) geometry with dynamic loading conditions in order to characterize the rheological properties (dynamic modulus and phase angle) of asphalt mixtures. Samples compacted in the laboratory or cored from in-service pavements can be used. A uniaxial state of stress is developed in the lower plane surface of the sample doing negligible the influence of the Poisson ratio on the dynamic modulus calculations. A specific experimental configuration was adopted and a 2D-FEM model has been used for the development of an equation for the calculation of the dynamic modulus. Two different asphalt mixtures were tested at diverse testing temperatures and loading frequencies. The obtained results have been analyzed and compared with those acquired with the more conventional testing configuration in uniaxial compression. An excellent agreement has been found for either the dynamic modulus or the phase angle with both sets of results. It could be concluded that the SCB configuration has been validated as a simple and promising methodology for the characterization of the viscoelastic response of asphalt mixtures.

Highlights

The rheological characteristics of asphalt mixtures have been traditionally determined in laboratory by different experimental procedures evaluating the viscoelastic properties under different conditions of loading frequencies and testing temperatures
In this paper the use of the Semi-Circular Bending (SCB) test configuration for the characterization of the rheological properties of asphalt mixtures is investigated. This configuration was selected because it is indicated that the SCB test possesses several advantages as the test setup is simple and virtually any loading frame used with other testing configuration can be adapted for the test, the used specimens can be prepared by sawing samples fabricated in the laboratory or cored in the field from in service pavements
The instrumentation of the sample is relatively simple and any testing equipment suitable for dynamic modulus measurements with other standardized procedures could be adapted in order to accommodate the geometry proposed in this study

Summary

Introduction

The rheological characteristics of asphalt mixtures have been traditionally determined in laboratory by different experimental procedures evaluating the viscoelastic properties (dynamic modulus and phase angle) under different conditions of loading frequencies and testing temperatures. In this paper the use of the Semi-Circular Bending (SCB) test configuration for the characterization of the rheological properties of asphalt mixtures is investigated. This configuration was selected because it is indicated that the SCB test possesses several advantages as the test setup is simple and virtually any loading frame used with other testing configuration can be adapted for the test, the used specimens can be prepared by sawing samples fabricated in the laboratory or cored in the field from in service pavements. Mull et al [5] have used the SCB configuration to evaluate the tensile strength on notched specimens to evaluate the fracture resistance of asphalt mixtures

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