Study of rheological properties of pure and polymer-modified Brazilian asphalt binders

In recent years, many authors have suggested techniques to study asphalt binders and establish structure-property correlations for these materials. Several works have shown that rheological analysis provides reliable information about the stability, elasticity, thermal susceptibility, and also that rheological behavior depends on chemical composition and structure of pure and modified binders. The objective of this work was to study the effect of the asphalt binder chemical composition and modifier polymer type on the linear viscoelastic properties and to correlate these properties to the PMB's thermal susceptibility. A set of polymer-modified asphalt binders (PMB) was prepared using two Brazilian asphalts. Both pure binders and PMB were analyzed by classical and dynamic rotational rheology tests. The rheological analysis results were also compared to storage stability data and PMB's morphology. The fitting capability of the Christensen-Anderson and Christensen-Anderson-Marasteanu rheological models was analyzed for the two pure asphalt binders. Both models presented lack of fitness in the regions of lowest and highest frequencies. When using elastomeric modifiers, it was possible to state the existence and interrelation between the width of the phase angle master curve plateau and the PMB's thermal susceptibility and stability. This interrelation was supported by PMB's storage stability data and microscopy analysis.