Characterizing the Asphalt-Aggregate Mixtures Using Rheological Properties of Asphalt Binders

Modeling techniques were employed to establish the relationship between the rheological properties (G* and δ) of asphalt binders and asphalt-aggregate mixtures. Results of this study indicate that the complex modulus and phase angle of the mixture can be represented by the same parameters obtained from the binder under the conditions of material linearity. This relationship is independent of frequency (or loading time) and temperature. For typical dense graded asphalt mixtures, the relationship is not significantly affected by the characteristics of both the asphalt binder and the aggregate. The relationship between the complex moduli of the asphalt binder and mixture can be mathematically modeled by the generalized power function. This function is more precise than the Heukelom and Klomp model (HK expression) and bilogarithm linear model (BL approximation), particularly at low and high modulus values. The generalized power function can differentiate asphalt binder as a viscoelastic liquid and asphalt mixture as a viscoelastic solid under the action of shear loading. The relationship of the phase angles, as an integrated part of rheological property of a viscoelastic material, between asphalt binders and mixtures can be modeled by a modified haversine function. This function completes the modeling of rheological properties as a whole for the first time and also reflects the fundamental material difference between the binder and the mixture in viscoelastic theory. Characterizing the asphalt mixture properties through the binder properties not only can save tremendous efforts in testing an asphalt mixture, but also can simplify the pavement performance prediction.