Quantitative phase analysis of hydraulic limes using the Rietveld method

Long-term leaching test in concretes: An X-ray powder diffraction study

“…This might be related to a low degree of crystallinity of portlandite, often observed in cement materials, which yields a relevant broadening of the diffraction peaks. The LX profile parameter of CH implies a small crystalline size, hinting at an amorphous Ca(OH) 2 fraction occurrence, attributed to calcium hydrate by thermal analysis but not revealed as portlandite by X-ray diffraction [21,35]. Note that: (i) the discrepancies between XRPD and DTA/TGA lie within the uncertainties affecting the CH-fraction values attained by the Rietveld method; (ii) DTA/TGA does not bring to light CH in DLT99_4, whereas XRPD does.…”

“…[20]) have attributed to XRPD a relevant role among the most widespread and promising characterisation techniques of polycrystalline materials, both in research and industrial laboratories. Note that studies on the use of XRPD for quantitative phase determination in cement paste have been reported by several authors, pointing out a good precision and accuracy of the attained results [21][22][23][24][25][26]. In such a view, a pilot study has been undertaken aimed at investigating the well-known leaching phenomenon on concretes by XRPD combined with the Rietveld method as a new approach for a direct quantification of portlandite dissolution.…”

An investigation to establish the source of the Roman lime mortars used in Wallsend, UK

“…The findings from the analysis of the mortars are broadly in line with the mineral assemblages identified by other authors (Andersen et al 2000;Maravelake-Kalaitzaki et al 2005). Gualtieri et al (2012) discussed the carbonation of brucite Mg(OH) 2 which would be formed during processing lime burning with dolomite. This would, they suggest result in amorphous Mg carbonate.…”

The micro-structural character of limestone and its influence on the formation of phases in calcined products: natural hydraulic limes and cements

“…% of internal standard (NIST676a corundum) was homogenized by hand in an agate mortar and added to the samples. This method allowed for the weight fraction of each phase in an unknown mixture to be calculated using the entire powder diffraction profile [52]. This requires knowledge of the crystal structures of all the phases present in the sample, and, in the case of amorphous phases being present, using a specific amount of internal standard [53].…”