Rutting and fatigue performance of asphalt mixtures containing amorphous carbon as filler and binder modifier

In this research amorphous carbon (AC) powder, a waste by-product from paraffin production, was used as a bitumen additive and filler material in asphalt mixtures to investigate its influence on rutting and fatigue behavior of asphalt binder and mixtures. For this purpose, multiple stress creep recovery and time sweep tests were conducted on asphalt binders; dynamic creep, Hamburg wheel track and four point bending beam fatigue tests were carried out as asphalt mixture tests to evaluate fatigue and rutting behavior of asphalt binders and mixtures. Results revealed that replacing up to 50% of filler material by AC powder improved the rutting performance and did not have substantial negative effect on fatigue resistance of asphalt mixtures. Using AC powder as bitumen modifier enhanced rutting resistance of both asphalt binders and their corresponding mixtures substantially. However, in spite of enhancing the rutting resistance and fatigue life at low strain levels, the use of more than 5% AC powder as a bitumen additive impaired the fatigue resistance of asphalt mixtures when exposed to high strain levels. From the results of this study to enhance rutting and fatigue performance of asphalt mixtures incorporation of 50% AC powder as filler material by weight of total filler, and 5% AC powder as bitumen additive is recommended.