ISSN: 0090-3973
Published Online: 8 April 2008
Page Count: 9

Interpretation of Complex Modulus Test Results for Asphalt-Aggregate Mixes
Levenberg, Eyal
Postdoctoral Researcher and Research Engineer, Purdue University, North Central Superpave Center, IN

Shah, Ayesha
Postdoctoral Researcher and Research Engineer, Purdue University, North Central Superpave Center, IN

(Received 16 November 2007; accepted 10 March 2008)

Abstract

In this paper, a slightly different approach than usual is suggested to interpret complex modulus results for asphalt-aggregate mixes. Similar to current/common methods, the proposed analysis “forces” the test data to comply with thermo-rheological simplicity and linear viscoelastic (solid) behavior. However, unlike current methods, use is made of both dynamic modulus and phase angle data to obtain a master curve along with the corresponding time-temperature shifting. This is done by assuming a mathematical expression for the relaxation spectrum instead of an equation for the dynamic modulus master curve. Consequently, better compliance with linear viscoelastic theory is a-priori ensured for all subsequent analyses. Moreover, using the proposed method, conversion of the test results from the frequency domain to the time domain arises as a natural and simple outcome of the procedure which does not require sophisticated inversion techniques that are known to be computationally problematic. Complex modulus test results obtained for three different asphalt mixes are presented and analyzed in order to demonstrate the applicability of the proposed method.

Keywords:
linear viscoelasticity, relaxation spectrum, complex modulus, dynamic modulus, phase angle, master curve

Paper ID: JTE101577
DOI: 10.1520/JTE101577
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