NON-LINEAR VISCOELASTIC AND FATIGUE PROPERTIES OF ASPHALT BINDERS

A study was conducted to relate linear visco-elastic properties of asphalt binders of the same PG-Grade to the rheological properties of asphalt mixtures of same aggregate source, gradation, and volumetric proportions. The only variable was the type of modifier used in the production of the binder. Results indicated that linear properties are not good indicators of mixture response. The study was expanded to evaluate the role of non-linear viscoelastic properties in mixture response. The results collected indicate that modified and un-modified asphalt binders vary significantly in the non-linear behavior. The non-linear study was expanded to include fatigue performance of binders at various strain levels in the linear and non-linear range. The paper presents a parametric study showing factors that influence strain dependency of asphalt binders of a wide variety of chemical composition and modification techniques. The results of fatigue testing of the binders are also presented to show factors that influence fatigue behavior. This paper is intended to stimulate the research on the non-linear behavior of binders and to suggest that non-linear properties are essential for effective estimation of the role of binders in mixture behavior.