Rejuvenating effect of soft bitumen, liquid surfactant, and bio-rejuvenator on artificial aged asphalt

Abstract

Challenges are existing when applying high percentages of reclaimed asphalt pavement (RAP) into construction as the aged RAP binder became more brittle, and stiffer after second-round usage. The bio-rejuvenator with dramatic environmental effects can alleviate stiffness and increases viscous components of aged RAP binder and is becoming popular in the incorporation with RAP. Unfortunately, till now, there is no research available to fully characterize and compare the regenerating effect between bio- rejuvenator, soft bitumen, and warm mix asphalt additives on high artificial RAP binder. To overcome this issue, in this study, a bio-rejuvenator and the other two rejuvenators including soft bitumen and Evotherm-DAT, were used to quantify the difference on regenerating effects of asphalt binder with different contents of artificial RAP binder. Penetration, softening point, rotational viscometer, dynamic shear rheometer (DSR), and bending beam rheometer (BBR) test were performed to characterize the basic properties, workability, and rheological properties of prepared samples. Test results showed that the bio-rejuvenator had the most effective rejuvenating impact, while its improvement on low-temperature performance was limited when it was used on binder containing 80% of artificial RAP binders. In addition, Evotherm-DAT had a significant softening effect on binder containing 30% of artificial RAP binders. Finally, it was found that Evotherm-DAT and bio-rejuvenator can perform well when maximum artificial RAP binder contents were 50% and 80%, respectively. The results of this study indicate possible uses of three different rejuvenators to improve the rejuvenating performance on the high percentage of RAP binder.