A dynamic modulus master curve for asphalt concrete is a critical input for flexible pavement design in the mechanistic-empirical pavement design guide developed in NCHRP Project 1-37A which has drawn much attention among asphalt technologists. The objectives in this study are to, 1) consider and compare different analysis techniques for construction of the master curve, and 2) measure and analyze the effect of permanent strain on samples that have been tested using the SPT modulus test. It was found that differences existed in the values of calculated asymptote values and shape of master curve depending upon which method was adopted. Recommendations are made for modifications to the testing protocol and further work to determine the effect of permanent strain at higher test temperatures. Rowe, Hakimzadeh, and Blankenship 3 EVALUATION OF ASPECTS OF E* TEST USING HMA SPECIMENS WITH VARYING VOID CONTENTS Geoffrey M. Rowe, Salman Hakimzadeh, and Phillip Blankenship INTRODUCTION The dynamic modulus of an asphalt mixture is a significant parameter that determines the ability of material to resist compressive deformation as it is subjected to cyclic compressive loading and unloading. The dynamic modulus test has been suggested by NCHRP Projects 9-19 and 9-29 as a simple performance test (SPT) to verify the performance characteristics of Superpave mixture designs (1). It has also been suggested as the potential quality control-quality assurance parameter in the field (2). Dynamic modulus is also an input to the Mechanistic-Empirical Pavement Design guide (MEPDG) (3) and supports the predictive performance models developed as part of NCHRP project 1-37A (4). For visco-elastic materials such as HMA mixtures, the stress-strain relationship under a continuous sinusoidal loading is defined by its complex dynamic modulus (E*). This is a complex number that relates stress to strain for linear visco-elastic materials subjected to continuously applied sinusoidal loading in the frequency domain. The complex modulus is defined as the ratio of the amplitude of the sinusoidal stress and the amplitude of the sinusoidal strain, as follows: