Title: Identifying non-linear HMA behaviour from uniaxial creep and dynamic modulus test results

Authors: Samer W. Katicha; Gerardo W. Flintsch; Amara Loulizi

Addresses: Center for Sustainable Transportation Infrastructure, Virginia Tech Transportation Institute, 3500 Transportation Research Plaza, Blacksburg VA 24061, USA. ' Center for Sustainable Transportation Infrastructure, Virginia Tech Transportation Institute, 3500 Transportation Research Plaza, Blacksburg VA 24061, USA. ' Ecole Nationale d'Ingénieurs de Tunis, BP 37, Le Belvédère 1002 Tunis, Tunisia

Abstract: Viscoelastic materials can be characterised using a number of tests of which the most commonly used for hot-mix asphalt (HMA) are creep and dynamic sinusoidal loading. For linear viscoelastic materials, the information obtained from these tests is essentially the same as the creep compliance and dynamic modulus are mathematically related through the convolution integral. In this paper, the non-linear response of HMA is studied by comparing uniaxial creep compliance and dynamic modulus test results. It is observed that non-linear behaviour occurs at high temperatures/reduced time. The specimen deformation response in the dynamic modulus test is used to confirm that the observed differences between the creep compliance and dynamic modulus test results are due to non-linearity and not just experimental error. Non-linear behaviour causes frequency modulation of the deformation response signal. The signal frequency is therefore non-stationary as illustrated by the instantaneous frequency calculated using the Hilbert-Huang transform.

Keywords: viscoelastic materials; nonlinear behaviour; hot-mix asphalt; Hilbert-Huang transform; HHT; instantaneous frequency; uniaxial creep; dynamic modulus; deformation; frequency modulation.

DOI: 10.1504/IJMMP.2012.050941

International Journal of Microstructure and Materials Properties, 2012 Vol.7 No.5, pp.380 - 389

Published online: 10 Dec 2012 *

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