Recent advances in characterizing the “bee” structures and asphaltene particles in asphalt binders

Yuhong Wang, Kecheng Zhao, Fangjin Li, Qi Gao, King Wai Chiu Lai

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

The microscopic surface features of asphalt binders are extensively reported in existing literature, but relatively fewer studies are performed on the morphology of asphaltene microstructures and cross-examination between the surface features and asphaltenes. This paper reports the findings of investigating six types of asphalt binders at the nanoscale, assisted with atomic force microscopy (AFM) and scanning transmission electron microscopy (STEM). The surface features of the asphalt binders were examined by using AFM before and after being repetitively peeled by a tape. Variations in infrared (IR) absorbance at the wavenumber around 1700 cm−1, which corresponds to ketones, were examined by using an infrared s-SNOM instrument (scattering-type scanning near-field optical microscope). Thin films of asphalt binders were examined by using STEM, and separate asphaltene particles were cross-examined by using both STEM and AFM. In addition, connections between the microstructures and binder’s physicochemical properties were evaluated. The use of both microscopy techniques provide comprehensive and complementary information on the microscopic nature of asphalt binders. It was found that the dynamic viscosities of asphalt binders are predominantly determined by the zero shear viscosity of the corresponding maltenes and asphaltene content. Limited samples also suggest that the unique bee structures are likely related to the growth of asphaltene content during asphalt binder aging process, but more asphalt binders from different crude sources are needed to verify this finding.

Original languageEnglish
Pages (from-to)697-706
Number of pages10
JournalInternational Journal of Pavement Research and Technology
Volume13
Issue number6
DOIs
Publication statusPublished - Nov 2020

Keywords

  • Asphalt aging
  • Asphalt microstructures
  • Asphaltenes
  • Atomic force microscopy
  • Scanning transmission electron microscopy

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Mechanics of Materials

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