Experimental investigation of the oxidative ageing mechanisms in bitumen

Experimental investigation of the oxidative ageing mechanisms in bitumen

Pipintakos, Georgios (Universiteit Antwerpen)
Vincent Ching, H. Y. (Universiteit Antwerpen)
Soenen, Hilde (Nynas NV)
Sjövall, Peter (Research Institutes of Sweden RISE)
Mühlich, Uwe (Universiteit Antwerpen)
Van Doorslaer, Sabine (Universiteit Antwerpen)
Varveri, Aikaterini (TU Delft Pavement Engineering)
Van den bergh, Wim (Universiteit Antwerpen)
Lu, Xiaohu (Nynas AB)

2020

Oxidative ageing in bituminous materials is considered one of the most important factors for distress types in road applications. This paper aims to offer insights into the validity of commonly held beliefs regarding the oxidation phases of ageing in bitumen, the fast- and the slow-rate phase, and explore the main oxidation products formed upon ageing. In order to evaluate possible differences between bitumen types, the penetration grade as well as the bitumen production process was varied. Thus, the ageing of three different binders was first studied by Fourier-Transform Infrared (FTIR) and Electron Paramagnetic Resonance (EPR) spectroscopy. The formation of oxygen-containing molecular structures on the bitumen surface during ageing was studied with Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). The results of FTIR reveal a gradual increase of sulfoxides upon ageing, while the EPR results show an increase of organic carbon-centred radicals. In parallel, TOF-SIMS results provide evidence for an increase of oxygenated compounds, such as SO_x^--, HO_x^-- and NO_x^--containing compounds. It appears also that paramagnetic metal species, such as vanadyl-porphyrins, are insusceptible during ageing. Overall, the findings of this study are in agreement with a mechanism comprising two rate-determining phases and support the formation of different oxygenated products. It is believed that the experimental approach used in this work may contribute further to an improved understanding of the ageing mechanisms in bitumen.

Ageing mechanisms
Bitumen
EPR
FTIR
TOF-SIMS

http://resolver.tudelft.nl/uuid:97241680-1607-4865-87e0-cf255f02b33f

https://doi.org/10.1016/j.conbuildmat.2020.119702

2021-05-10

0950-0618

Construction and Building Materials, 260

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2020 Georgios Pipintakos, H. Y. Vincent Ching, Hilde Soenen, Peter Sjövall, Uwe Mühlich, Sabine Van Doorslaer, Aikaterini Varveri, Wim Van den bergh, Xiaohu Lu