Neutron and X-ray Rietveld quantitative phase analysis of industrial Portland cement clinkers

Weight fractions of four dominant phases (C3S, C2S, C4AF and C3A) present in five industrial clinkers were estimated by a series of neutron and X-ray Rietveld refinements. Calculated powder patterns were derived from the structural data for triclinic and monoclinic C3S, monoclinic C2S, orthorhombic C4AF and cubic C3A. Neutron diffraction data were collected with the high resolution E9 diffractometer (BENSC) using the wavelengths of 1.797Å and 2.816Å, X-ray diffraction data with a high resolution transmission diffractometer using CoKα1 radiation. Elemental composition of the samples obtained by ESEM/EDX technique were in a good agreement with the data delivered by the producers. Convergence of the refinements was remarkably different for X-ray and for neutron data. Several refinements were not completed due to numerical instabilities. Neutron refinements were found to be more stable than X-ray, but there was not any notable difference in the final estimated phases' compositions. Calculated absolute deviates of phases' weight fractions were mostly within ±10%, which for the less abundant phases corresponded to relative deviations within ±50%