Computer controlled characterization of X-ray diffraction (XRD) spectra of asphalt binder were studied with respect to X-ray background type, profile fit and dimensional analysis. Four different background types (linear, parabolic, 3rd and 4th order polynomial) were used in order to assess the precision of fit and residual error of fit. Mathematical functions (Pearson VII, pseudo-Voigt, generalized Fermi) are also employed in this analysis. When varying the Pearson VII exponent (1.6, 2.0) and pseudo-Voigt Lorentzian (1.0) constant the results show an effect on the X-ray peak position and calculated average size of crystallite parameters. The interlayer distance between the aromatic sheets (dM) was determined to be between 4 to 5 angstroms and the distance between the saturated portions (d?) at 5 to 7 angstroms. For all cases the lowest residual error of fit was the 4th order polynomial X-ray background type.
