Correlation between the characterization of bee structures and chemical composition/nano-scale mechanical property of bitumens

The characterization of the bee structures which is observed on the surface of bitumens by atomic force microscopy (AFM) has received increasing attention in recent two decades. This study is initiated to develop a method to quantitatively evaluate the dispersed nature of bee structures, and investigate the correlation between the topographical characteristics of bee structures and the laboratory measured properties of bitumens. The AFM images of bitumens are obtained and further processed with image process technique. The data collected from Delaunay triangles are statistically analyzed. Experiments are conducted to measure four fractions, molecular distributions, and dynamic modulus of the bitumens. It is found that the dispersion of bee structures can be reasonably evaluated by the proposed method. The type of bitumens significantly affects the topographical characteristics of bee structures including major axis, aspect ratio, area, and wavelength. The asphaltenes content and the viscoelastic property of bitumens can be estimated using aspect ratio of bee structures with R2 value of over 0.97. The results will benefit a comprehensive understanding of bitumen microstructure and may potentially assist practical applications such as performance-related design for bituminous materials. (C) 2019 Elsevier Ltd. All rights reserved.