New direct observations of asphalts and asphalt binders by scanning electron microscopy and atomic force microscopy

TLDR

SEM observation requires adequate sample preparation. The study combines AFM, SEM, and fluorescence microscopy to examine asphalt structure, enabling observation without pre‑preparation and revealing polymer‑induced structural changes. The observations reveal a network of asphaltene molecules in asphalt gel, with SEM providing higher resolution, and show that polymer addition rearranges asphaltene associations, implying polymer aggregates the asphaltene phase.

Abstract

Observations made using AFM and SEM have been combined in order to study the structure of asphalts. Fluorescence microscopy was used to aid in understanding the structural changes occurring when polymer is added to the asphalts. With the atomic force microscope we are able to study the structure of the asphalts without any pre‐preparation. Despite very low resolution, our study reveal ed a network of asphaltene molecules with regard to asphalt gel. The same result is obtained by SEM observation but with a much better resolution. SEM observation, however, needs an adequate preparation method. In the presence of polymer we observed a rearrangement of the initial asphaltene association which leads to the assumption that polymer can aggregate the asphaltene phase.