Potentials for the quantification of the chemical microstructure of modified bitumen

Abstract

This research investigated the potential for quantifying the microstructural features of montmorillonite-modified bitumen by Fourier-transform infrared (FTIR) microscopy to simultaneously visualise the micro-phase and chemically characterise them by FTIR spectroscopy. The analysis was based on the successive thresholding of the micrographs representing integrals of the FTIR spectra from 960 to 1100 cm−1. The characterisation included size distributions and spatial arrangements of peak-value regions, and the local thickness distributions of the surrounding space. The arrangement of regions of modifier’s high concentration was mostly randomly heterogeneous, while the thresholded area fraction barely affected the assessment of agglomeration. In agglomerated areas, the local peaks seemed to repel each other. Microstructural manifestations of ageing were recognised to be the most promising application of this approach. Moreover, there is a huge potential for evaluating interfacial chemical interactions like diffusion in polymer-modified bitumens.