Rheological properties of warm mix asphalt binders and warm mix asphalt binders containing polyphosphoric acid

This paper presents the laboratory investigation of properties of warm mix asphalt (WMA) binders and WMA binders containing polyphosphoric acid (PPA).Two types of warm mix additives were used to produce the WMA binders. Superpave tests were carried out on original and short-term aged binders through the rotational viscometer, the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). The results indicated that the WMA binders with different warm mix additives showed different viscosity values, however, the addition of PPA remarkably increased the viscosity values of these two kinds of WMA binders used, in the present study, to a similar level. The WMA additive type and the PPA had significant effects on the complex modulus ( G * ), phase angle ( δ ) and G ∗ / sin δ regardless of the binders’ aging state (without aging or short-term aging). In addition, two WMA binders with different additive types showed significant differences on the creep stiffness and m -value, and the addition of PPA degraded the low temperature rheological properties of the WMA binders.