Exploring the oxidative mechanisms of bitumen after laboratory short- and long-term ageing

• The oxidative mechanisms in bitumen were studied after laboratory short- and long-term ageing. Three binders of varying crude source, distillation, performance wax presence investigated. 1 H NMR demonstrated slight changes the relative proton distribution upon EPR supported an increase organic carbon-centred radicals short-term TOF-SIMS revealed SO x -, (OH) -containing compounds because Understanding fundamental ageing is considered paramount importance order to take steps towards durable able tackle distresses related this phenomenon which deteriorates asphalt performance. This paper focuses on identification intermediate final oxygenated products simulated with rolling thin-film oven testing (RTFOT) pressurised vessel (PAV) respectively. investigated study, two originated from same wax-free while third was obtained a different containing natural wax, followed manufacturing process. Fourier-Transform Infrared (FTIR) spectroscopy clear sulfoxide carbonyl functional groups for all independently origin, or Electron Paramagnetic Resonance (EPR) showed (RTFOT), whereas PAV these remained constant originating even decreased third, waxy binder. Proton Nuclear Magnetic ( NMR) reported differences protons between unaged state, similar minor both regardless binder’s source distillation. results Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) that - are produced sequentially occurring bitumens, almost behaviour aliphatics can be seen bitumens. Finally, strengths weaknesses each experimental techniques reviewed compared versus possible mechanisms.