Rheological and chemical characteristics of warm mix asphalt binders at intermediate and low performance temperatures

Warm asphalt has been gaining increasing popularity in recent years around the world due to many reasons including the energy reductions and environmental benefits. In the present study, the objective was to conduct a laboratory investigation of rheological properties of eight binders with four non-foaming warm mix asphalt (WMA) additives at intermediate and low performance temperatures in terms of Superpave low temperature test criteria. The conventional testing procedures such as dynamic shear rheometer (DSR), bending beam rheometer (BBR) test as well as specific Fourier transform infrared spectroscopy (FTIR) were performed to determine the influences of non-foaming additives on asphalt binders after a long-term aging procedure. The test results indicated that the binder type and source play key roles in determining the G*sin delta values of WMA binders with the non-foaming WMA additive. All eight binders containing Sasobit generally have higher creep stiffness values compared to the binders with other WMA additives. The FTIR tests illustrated that the absorbance of the C-O stretch and C-H bend regions of the WMA binders after a short and long-term aging procedure can be considered similar. Moreover, the WMA binders generally exhibit better performance properties than control binders at intermediate and low temperatures after a long-term aging procedure. Furthermore, FTIR analysis results indicate that the binder type and source play important roles in determining the rheological properties of WMA binders.