Quantitative in situ X-ray diffraction analysis of early hydration of belite-calcium sulfoaluminate cement at various defined temperatures

Maruša Borštnar (Author), Christian L. Lengauer (Author), Sabina Kramar (Author)

Abstract

The influence of temperature on the early hydration of belite-calcium sulfoaluminate cements with two different calcium sulfate to calcium sulfoaluminate molar ratios was investigated. The phase composition and phase assemblage development of cements prepared using molar ratios of 1 and 2.5 were studied at 25, 40 and 60 ◦C by in situ X-ray powder diffraction. The Rietveld refinement method was used for quantification. The degree of hydration after 24 h was highest at ambient temperatures, but early hydration was significantly accelerated at elevated temperatures. These differences were more noticeable when we increased the temperature from 25 ◦C to 40 ◦C, than it was increased from 40 ◦C to 60 ◦C. The amount of calcium sulfate added controls the amount of the precipitated ettringite, namely, the amount of ettringite increased in the cement with a higher molar ratio. The results showed that temperature also affects full width at half maximum of ettringite peaks, which indicates a decrease in crystallite size of ettringite at elevated temperatures due to faster precipitation of ettringite. When using a calcium sulfate to calcium sulfoaluminate molar ratio of 1, higher d-values of ettringite peaks were observed at elevated temperatures, suggesting that more ions were released from the cement clinker at elevated temperatures, allowing a higher ion uptake in the ettringite structure. At a molar ratio of 2.5, less clinker is available in the cement, therefore these differences were not observed.

Keywords

in situ rentgenska difrakcija;hidratacija;temperatura;cement;rietveldova analiza;odprti dostop;in situ X-ray diffraction;hydration;temperature;rietveld analysis;open access;

Data

Language:	English
Year of publishing:	2021
Typology:	1.01 - Original Scientific Article
Organization:	ZAG - Slovenian National Building and Civil Engineering Institute
Publisher:	MDPI AG
UDC:	620.1/.2
COBISS:	54931459
ISSN:	2075-163X
Views:	6
Downloads:	0
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary keywords:	in situ rentgenska difrakcija;hidratacija;temperatura;cement;rietveldova analiza;
Source comment:	Nasl. z nasl. zaslona; Opis vira z dne 12. 3. 2021;
Pages:	str. 1-21
Volume:	ǂVol. ǂ11
Issue:	ǂno. ǂ3
Chronology:	Mar. 2021
DOI:	10.3390/min11030297
ID:	19394479