Quantitative in situ X-ray diffraction analysis of early hydration of belite-calcium sulfoaluminate cement at various defined temperaturesMrak, Maruša (Avtor) Lengauer, Christian L. (Avtor) Dolenec, Sabina (Avtor) in situ X-ray diffractionhydrationtemperaturecementrietveld analysisThe 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.MDPI AG20212022-11-30 10:52:12Neznano15853UDK: 620.1/.2ISSN pri članku: 2075-163XDOI: 10.3390/min11030297COBISS_ID: 54931459sl© 2021 by the authors. Licensee MDPI, Basel, Switzerland.