ASTM C1365-18 PDF Download

ASTM C1365-18 is a standard test method that allows for direct determination of the proportion of individual phases in Portland cement and Portland-cement clinker using X-ray powder diffraction analysis. It serves as an alternative to the indirect estimation of phase proportion using equations in Specification C150/C150M (Annex A1).

This test method assumes that the operator is qualified to operate an X-ray diffractometer and interpret X-ray diffraction spectra. It can be used as part of a quality control program in cement manufacturing and can also be used to predict properties and performance of hydrated cement and concrete that are dependent on phase composition.

It is important to note that the results obtained through quantitative X-ray diffraction (QXRD) analysis provide a bulk analysis, representing the weighted average composition of several grams of material. Therefore, there may be slight variations compared to results obtained through microscopical methods.

The standard covers the determination of the proportion by mass of various phases, including tricalcium silicate (alite), dicalcium silicate (belite), tricalcium aluminate (aluminate), tetracalcium aluminoferrite (ferrite), magnesium oxide (periclase), calcium sulfate dihydrate (gypsum), calcium sulfate hemihydrate (bassanite), calcium sulfate (anhydrite), and calcium carbonate (calcite).

While the standard specifies certain general aspects of the analytical procedure, it does not provide detailed instructions. Recommended procedures are described, but not mandated. It is the responsibility of the user to demonstrate through analysis of certified reference materials that the chosen analytical procedure provides acceptable precision and bias.

The values in this standard are stated in SI units and should be regarded as the standard for this test method.