Recycling of aged asphalt binders with wax warm additives

Abstract

Warm mix asphalt (WMA) has been used in pavement industry since 2000. While there were several studies related to WMA performances, recycling characteristics of WMA binders are not investigated in detail. Rudimentary performances of recycled binder with wax warm additives were evaluated through a series of Superpave binder tests. WMA binders were produced using two wax additives of LEADCAP and Sasobit, and then artificially short-term and long-term aged using the rolling thin film oven and pressure ageing vessel procedures. The control binder was mixed with aged binders at two recycling contents of 15% and 30%. Superpave binder tests were carried out on the binders through the rotational viscometer, the dynamic shear rheometer, and the bending beam rheometer. In general, the results of this study indicated that (1) the addition of warm asphalt additives considerably improves the high-temperature properties of control and recycled binders, (2) the recycling contents played a significant role in determination of the binder properties, and (3) the wax additives in recycled WMA binder were still effective to improve viscosity and rutting properties, even though those additives experienced short- and long-term ageing processes.