The influence of wax model compounds on the surface topography of bitumen

In literature, microscopy techniques including atomic force microscopy (AFM), scanning electron microscopy (SEM) and recently also confocal laser scanning microscopy (CLSM) have been used to study the microstructure of bitumen. Es-pecially by AFM, various surface morphologies have been observed. Well-known are the so-called Bee structures, related to a regular height profile of lower and higher regions. The appearance of these microstructures has been linked to the presence of crystallizing waxes. In addition to this, other regions surround-ing, or in between the Bee structures have been described. These have been re-ferred to as the perpetua or peri structures, and very little is known about the origin or formation of these phases. In this study, straight, saturated hydrocarbons of specific chain lengths, were added to a wax-free naphthenic bitumen, and the air-bitumen interfaces were in-vestigated by AFM. As expected, the unmodified bitumen did not display any topological microstructure, and by adding waxes to this binder, Bee structures could be generated. However, not only Bee structures were obvious, but the in-termediate phases could also be generated under certain conditions. The chain length of the waxes, as well as their blending ratios were the determining parame-ters for the type of structures that were formed. So, in conclusion, this study demonstrates that not only the Bee structures, but also the intermediate and/or surrounding structures are related to the presence of waxy hydrocarbons, and no other molecular structures are needed or involved in the formation of these structures.

ISBN:978-3-030-46454-7

Publication year:2022

Keywords:P1 Proceeding

Accessibility:Open