Understanding the bitumen ageing phenomenon: A review

The ageing phenomenon in asphalt mixtures is one of the most important factors affecting its service life. The current paper provides an overview of a number of studies related to the ageing process in bitumen, to determine the main component affecting this phenomenon. Moreover, a review is presented of the in laboratory tests used to simulate the different ageing processes (short-term ageing, long-term ageing, UV ageing) that occur in the field, along with a description of the techniques currently employed to analyse, from different perspectives, what happens to the binder after ageing. Finally, a summary is presented of the various types of anti-ageing additives (antioxidants, UV blockers, UV absorbers) that are currently most commonly studied, along with their effects. This document reveals the importance of assessing the influence of UV radiation in any ageing study that is related to field data, and the need for a standard to simulate bitumen ageing. In addition, it highlights the importance of considering the influence of other components of the mixture on the ageing of the bitumen and the need to conjointly consider different types of techniques in order to fully understand the phenomenon. (C) 2018 Elsevier Ltd. All rights reserved.