Calibration of grayscale values of cement constituents using industrial X-ray tomography

X-ray computer tomography (CT) has been intensively applied to the research of cement-based materials, while most of the CT applications are qualitative. To have more quantitative applications, the arbitrary grayscale values and the specially defined CT numbers of the main cement constituents, including the cement clinkers, the hydrated products, and some durability products are calibrated on an industrial CT system in this study. The calibration results can deepen our understandings of the X-ray CT image of the cement-based materials. The universalities of the calibrated results and the calibration procedures are clarified. The potential applications are anticipated, such as segmentation of the individual phases, quantitative durability research, porosity determinations, and quantitative composition characterizations.