Jawaher Alshammari1, Jihan Alshammari1, John K C Lewis1, John Shirokoff2
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
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, 3rd and 4th 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 (dM) was determined to be between 4.3 to 4.8 angstroms and the distance between the saturated portions (dγ) at 5.7 to 6.9 angstroms. For all cases the lowest residual error of fit was the 4th order polynomial X-ray background type.
Keywords: Asphalt binder; X-ray diffraction; Spectral line shapes; Fitting; Plotting; Modeling