Identification of viscoelastic functions for hot-mix asphalt mixtures using a modified harmony search algorithm

This study proposes a modified harmony search (MHS) algorithm for determining the time-domain viscoelastic function of hot-mix asphalt (HMA) concrete materials. This MHS technique, employing a global optimization technique as well as a Wiechert model for the relaxation function, substantially enhances accuracy and consistency in the determination of viscoelastic functions of several HMA mixtures. In addition, this study shows how to determine a time-domain Prony series representation from the complex modulus in the frequency domain using the MHS algorithm. This can be efficiently used for numerical analysis with techniques such as the finite-element method. The results from lab frequency sweep tests of unmodified and lime-modified HMA at various asphalt contents were consistent with the functions obtained from the MHS algorithm.