Nanosize Asphaltene in Asphalt Binders Characterized by X-ray Diffraction

¹Physics and Physical Oceanography Department, Memorial University Newfoundland, St. John’s, NL, Canada
²Process Engineering Department, Memorial University Newfoundland, St. John’s, NL, Canada

*Corresponding author: John Shirokoff, Process Engineering Department, Memorial University Newfoundland, St. John’s, NL, Canada A1C5S7.

Received: November 10, 2019
Published: November 26, 2019

ABSTRACT

Computer controlled X-ray diffraction (XRD) spectra of asphalt binders were studied with respect to X-ray background type, profile fit and dimensional analysis. Four different background (linear, parabolic, 3^rd and 4^th order polynomial) types were used in order to assess profile fit (precision, residual error) the precision of fit and residual error of fit. Pearson VII, pseudo-Voigt, generalized Fermi mathematical functions were employed in this analysis. When varying the Pearson VII exponent (1.6, 2.0) and pseudo-Voigt Lorentzian at constant value (1.0) the results show an effect on the X-ray peak position and calculated average size of crystallite parameters. Interlayer distance between aromatic sheets (d_M) was determined to be between 4.3 to 4.8 angstroms and the distance between the saturated portions (d_γ) at 5.7 to 6.9 angstroms. For all cases the lowest residual error of fit was the 4^th order polynomial X-ray background type.

Keywords: Asphalt binder; X-ray diffraction; Spectral line shapes; Fitting; Plotting; Modeling