Quantitative Rietveld analysis of the amorphous content in cements and clinkers

The potential presence of an amorphous content in OPC clinker and cements is usually overlooked when studying their phase composition. This is largely because of the difficulty in determining amorphous content experimentally. Despite this difficulty, the study of amorphous content and composition in these materials has merit due to the likely effects on the reactivity of the resulting cement. This paper applied the Rietveld method using X-ray powder diffraction data to determine the amorphous content of a number of materials, including clinker, cements and single phases. The cementitious materials were found to contain widely varying, but significant, amorphous contents. The addition of amorphous slag to change the amorphous content by a known amount, gave results as expected from the calculated results for the pure cement and clinker amorphous contents. The results are discussed in relation to other studies published on the issue of amorphous content in cementitious materials.