Characterization of rutting performance of warm additive modified asphalt mixtures

Driven by the reduction in fuel consumption and CO2 emission in producing and placing asphalt concrete, the warm technology has gained a lot of interests in the recent years in academia and/or industry. Warm additives are available both in a liquid and solid state; there are concerns over the rutting performance of WMA. The purpose of this study is to investigate and characterize the effects of various warm additives on the rutting performance of asphalt concrete with different binders and mixing temperature applications. The results showed that the lowered mixing temperature increases the rutting susceptibility due to reduced binder aging. The wax warm additives stiffen the binder, and can offset the rutting problem rendered by the lowered mixing temperature, while the chemical warm additives have the same rutting performance as the control mixtures.

► Lowering mixing temperature in WMA increases the rutting susceptibility.
► The rutting differences between wax and chemical additives are distinct.
► The wax additives stiffen the binder and offset the rutting susceptibility in WMA.
► Chemical warm additives perform the same as the virgin binder in rutting.
► The recovered binders’ G*/sin δ had a weak correlation with the rutting performance.