[Zurück]

H. Grothe, F. Handle, D. Großegger, S. Neudl:
"Observing the Microstructure of Bitumen by Fluorescent Spectroscopy and Microscopy";
Vortrag: TURCMOS 2013, Istanbul; 15.09.2013 - 20.09.2013; in: "Book of Abstracts", (2013), S. 62.

The definition and improvement of asphalt concrete is the great challenge the ever rising expectations and requirements of roadworks puts in front of the bitumen industry. Thus, the search for techniques
allowing an assessment of the adhesive and rheological properties of bitumen is very essential. Confocal Laser Scanning Microscopy (CLSM) is an advanced imaging technique that enables structural analysis of very complex materials due to the combination of highly localized chemical information and improved signal power. Complementary spectroscopic analysis, however, is essential to unravel the
sophisticated material behaviour of complex organic composites as bitumen.

CLSM allows the detailed study of the microstructure of bitumen by visualizing fluorescent centres in bitumen. The origin of these fluorescence signals has been the subject of on-going debate. Fluorescence spectroscopy is employed in combination with chromatographic separation techniques to obtain new evidence regarding the composition and ageing behaviour of asphaltene micelles.

The combined results reveal that the aromatic mantle, serving as a stabilizing agent around the micelle, is the source ofthe fluorescent emissions, which contradicts the concept that the asphaltenes themselves would show fluorescent emissions. These facts serve as the basis for an updated micelle model, capable of describing both the visualized microstructure and explaining the ageing behaviour of asphalt concrete in respect to thermal healing of asphalt.

fluorescent microscopy, fluorescent spectroscopy, petrol industry, roadworks