Bitumen reuse: physical and chemical approach to investigate the effectiveness of rejuvenators
Kim Schwettmann, Nina Nytus, Martin Radenberg, Dietmar Stephan
Abstract
This study investigates a cyclic reuse of bitumen. In the first life cycle, only virgin bitumen is used, which is reused in the second life cycle through rejuvenators. The reuse rates of the bitumen samples are 100%, so no fresh binder is added in the second life cycle. At the beginning of the research a calculation method based on the equi-shear modulus temperature T(|G*| = 15 kPa) is used to determine the optimal rejuvenator dosages. For the rejuvenators, a wide range of dosages between 6% and 48% is found, which displays the diversity of the products available on the market. For the evaluation of the rejuvenators' performances , a comprehensive investigation programme of physical and chemical methods is carried out. Results show that not only the rejuvenation effect but also the effect of the rejuvenator on subsequent ageing should be considered when evaluating the effectivness.