A HYDRATION STUDY BY XRD/RIETVELD ANALYSIS OF CEMENT REGENERATED FROM COMPLETELY RECYCLABLE CONCRETE

Mieke De Schepper, Klaartje De Buysser, Isabel Van Driessche, Nele De Belie

Abstract: In today’s cement and concrete research, mineralogical quantification of (un)hydrated cement samples by X-ray Diffraction/Rietveld analysis becomes more and more important. As the results from XRD/Rietveld analysis are becoming increasingly more accurate, it became a widely used tool to study the hydration of cementitious materials besides other techniques e.g. isothermal calorimetry or thermogravimetric analysis. To quantify amorphous or non-identified phases, an internal standard might be added to estimate these so-called ‘other’ phases. Compared to unhydrated samples which are almost completely crystalline, it has a higher significance in hydrated samples, as certain cement hydrates, such as C-S-H, hydrogarnet, hydrotalcite, AFm, etc., are often poorly crystalline. Within the development of Completely Recyclable Concrete (CRC – a concrete designed for reincarnation within the cement production following the Cradle-to-Cradle Principle) the hydration of the regenerated cement was assessed by XRD/Rietveld analysis. Within this study it was found that the particle size distributions of the sample and the internal standard should not be underestimated within the quantification of the ‘other’ phases

Keywords: X-ray diffraction, Cement hydration, amorphous material

DOI: https://doi.org/10.15623/ijret.2014.0325021