Analysis of hydration products, hydration degree, and CO 2 capture in “ye'elimite –H 2 O” system by X-ray diffraction, combined SEM-EDS, and FTIR techniques

By application of the XRD, combined SEM-EDS, and FTIR techniques, this study analyzes morphology, chemical elemental composition, and carbonation of the hydration products precipitated in “ye'elimite–H 2 O” system. The hydration experiment was conducted at a w/y ratio by weight of 3 and a long hydration time of 270 days and resulted in precipitation of the ettringite, gibbsite, and calcite. The hydration degree (≈ 85%), the actual amount of the captured CO 2 (≈ 0.14g/g), and the maximum CO 2 capture capacity (≈ 0.22g/g) of the ye'elimite as a result of the hydration process are evaluated on the bases of a combined analysis of the proposed net hydration reaction and recorded SEM-EDS data. The uptake of CO 2 by hydrated ye'elimite is contributed by calcite and carbonated ettringite. The data of SEM-EDS measurements are also used for confirmation of the mechanism proposed in literature for explanation of the retardation of the ye'elimite hydration by the gibbsite. The results reported in this study may be useful (i) in terms of analysis of the hydration products that are formed as a result of hydration of the ye'elimite and commercial ye'elimite-rich cements and (ii) for quantitative analysis of the captured CO 2 by hydrated ye'elimite and ye'elimite-rich cements.