State of the art: Multiscale evaluation of bitumen ageing behaviour

TLDR

Ageing is a common phenomenon that seriously affects the performance and service life of asphalt pavements. The paper reviews multiscale evaluations of bitumen ageing to better understand the ageing mechanism and to inform future anti‑ageing and binder rejuvenation efforts. It surveys conventional and bespoke ageing methods and then concentrates on macro, meso, micro and nano‑scale assessments using DSC, TGA, TLC‑FID, GPC, FTIR, AFM, optical and fluorescence spectroscopy, NMR, TOF‑SIMS and molecular dynamics simulations. The review highlights intricate correlations between hierarchical scales and demonstrates that a multiscale approach is essential for a comprehensive understanding of bitumen ageing.

Abstract

Ageing is a common phenomenon that seriously affects the performance and service life of asphalt pavements. In this paper, multiscale evaluations of bitumen ageing behaviour were reviewed to better understand the bitumen ageing mechanism and thereby contribute to future anti-ageing and binder rejuvenation work in this area. The paper initially looks at conventional as well as bespoke ageing methods before concentrating on bitumen ageing evaluation at different scales ranging from macro, meso, micro to nano scale. This is done by introducing the application of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) in thermal indices; thin-layer chromatography-flame ionization detector (TLC-FID), gel permeation chromatography (GPC) and Fourier infrared spectrometer (FTIR) in components and functional groups; atomic force microscopy (AFM), optical spectroscopy and fluorescence spectroscopy (FM) in microstructural analysis; and, finally, nuclear magnetic resonance (NMR), time-of-flight secondary ion mass spectrometry (TOF-SIMS) and molecular dynamic simulations at the nanoscale. This review paper highlights the intricate correlations between the different hierarchical scales of bitumen ageing and the importance of a multiscale approach to provide a more comprehensive study and understanding of the ageing of bitumen.