Impact of Anti-Ageing Compounds on Ageing Kinetics of Bitumen by Infrared Spectroscopy Analysis

This paper investigates the effect of anti-ageing additives on the oxidation kinetics of bitumen using Fourier Transformation Infrared Spectroscopy technique (FTIR). Twenty different anti-oxidant compounds were added to bitumen (asphalt binder) and subjected to laboratory oven ageing conditioning. Those modifiers included a few known anti-ageing materials, recently proposed compounds for asphalt mixtures, polymer modifiers and other new compounds. Normalized Carbonyl Index has been proposed to quantify the amount of oxidation for the bitumen modified by the anti-ageing additives, while the activation energy of fast-rate oxidation was determined and utilized for the initial screening and optimization of effective anti-ageing compounds. The additive Irganox acid of 15% concentration, achieved best results in preventing fast-rate ageing under the tested conditions. This study proposed an initial screening and analysing methodology for testing bitumen anti-ageing additives, that could provide a subjective primary idea of the additives’ effectiveness at reducing ageing rate, however, it should be followed by detailed laboratory ageing and rheology tests for the anti-ageing materials final nomination.