How to Construct an Asphalt Binder Master Curve and Assess the Degree of Blending between RAP and Virgin Binders

Abstract

The master curve of an asphalt binder provides a relationship between the binder stiffness and reduced frequency over a range of temperatures and frequencies. Accordingly, the master curve makes it possible to predict viscoelastic properties over a wide frequency range and also to predict viscoelastic properties at any temperature. To construct a master curve, the stiffness of an asphalt binder at multiple temperatures and frequencies is measured. The data are then fitted into a viscoelastic model applied to asphalt binders. Recently, a methodology has been developed that utilizes the measured dynamic modulus of a hot-mix asphalt (HMA) mixture and the master curves for the as-recovered binders to determine the degree of blending between aged and virgin binders in asphalt mixtures that incorporates recycled materials. This study presents the methodology for constructing asphalt binder master curves in a step-by-step format. The study also describes in a step-by-step format the methodology for evaluating the degree of blending between aged and virgin binder. Furthermore, to clarify the method and elaborate on the analysis of experimental results, plant-produced mixtures containing different percentages of recycled asphalt pavement (RAP) were obtained and tested. The test results were used to develop the master curves and examine the degree of blending by the aid of the methodology explained in the paper.