Thermal methods and microcalorimetry application in the studies of low energy cements

Rajczyk, K.; Nocuń-Wczelik, Wiesława

doi:10.1007/bf01979407

Cited by 2 publications

(3 citation statements)

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“…So, a CSA clinker was mixed with 25 wt% of crystalline gypsum [CaSO 4 ·2H 2 O or C S H 2 , in cement nomenclature (cement nomenclature: C = CaO, S = SiO 2 , A = Al 2 O 3 , F = Fe 2 O 3 , S = SO 3 , M = MgO, and T = TiO 2 )], labeled as 25G_CSA. The accuracy of the quantitative analysis of gypsum in this sample was confirmed by comparison to the weighed value and also to the value obtained from an alternative technique differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA) (Rajczyk and Nocun-Wczelik, 1992). Hence, the sample was heated from RT to 1273 K at a rate of 10° min −1 , and its mass variation was accurately monitored.…”

Section: Resultssupporting

confidence: 52%

“…, labeled as 25G_CSA. The accuracy of the quantitative analysis of gypsum in this sample was confirmed by comparison to the weighed value and also to the value obtained from an alternative technique differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA) (Rajczyk and Nocun-Wczelik, 1992). Hence, the sample was heated from RT to 1273 K at a rate of 10°min −1 , and its mass variation was accurately monitored.…”

Section: Constant Volume Assumptionmentioning

confidence: 65%

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Rietveld quantitative phase analysis with molybdenum radiation

et al. 2014

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Building materials are very complex samples of worldwide importance, hence quantitative knowledge of their mineralogical composition is necessary to predict performances. Rietveld quantitative phase analysis (RQPA) allows a direct measurement of the crystalline phase contents of cements. We highlight in this paper the use of laboratory x-ray powder diffraction (LXRPD) employing high energy radiation, Mo, for attaining the RQPA of cements. Firstly, we evaluate the accuracy of RQPA employing a commercial calcium sulfoaluminate clinker with gypsum. In addition to Mo Kα 1 and Mo Kα 1,2 radiations, Cu and synchrotron patterns are also analyzed for the sake of comparison. Secondly, the assessment of the accuracy of RQPA results obtained using different radiations (synchrotron, Mo and Cu) and geometries (reflection and transmission) is performed by analyzing two well known commercial samples. As expected, for LXRPD data, accuracy in the RQPA results improves as the irradiated volume increases. Finally, three very complex aged hydrated cements have been analyzed using MoKα 1 -LXRPD and Synchrotron-XRPD. The main overall outcome of this work is the benefit for RQPA of using strictly monochromatic Mo Kα 1 radiation. Best laboratory results arise from Mo Kα 1 data as the effective tested volume is much increased but peak overlapping is not swelled.

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Section: Resultssupporting

confidence: 52%

Section: Constant Volume Assumptionmentioning

confidence: 65%

Rietveld quantitative phase analysis with molybdenum radiation

et al. 2014

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“…The precision of the quantitative analysis of gypsum, bassanite, portlandite and calcite was confirmed by comparison with other quantification techniques such as DTA (differential thermal analysis) and TGA (thermogravimetric analysis) (Rajczyk & Nocun-Wczelik, 1992). A crushed sample is heated from RT to 1273 K at a rate of 283 K min À1 , and its mass variation is accurately monitored.…”

Section: Commercial Samplesmentioning

confidence: 87%

Round robin on Rietveld quantitative phase analysis of Portland cements

et al. 2009

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Interlaboratory studies on the precision and accuracy of Rietveld quantitative phase analysis (R‐QPA) of mixtures of crystalline phases have already been carried out. However, cement‐related materials are samples of variable complexity, ranging from three phases in white Portland clinkers to more than eight phases in grey cements, that need to be specifically investigated. Here, the results are reported from a round robin on the R‐QPA of cement‐related materials from laboratories with experience in this type of analysis. The aim of the work was to evaluate the levels of precision and accuracy associated with Portland clinkers and cements. Two sets of samples have been investigated, artificial mixtures and commercial samples. Artificial mixtures were prepared by mixing (weighing) synthesized single‐crystalline phases in the appropriate proportions: (i) white clinker (Ca3SiO5, Ca2SiO4 and Ca3Al2O6) and (ii) grey cement (Ca3SiO5, Ca2SiO4, Ca3Al2O6, Ca4Al2Fe2O10, CaCO3 and CaSO4·2H2O). These two samples were used to assess the accuracy and uncertainty of the procedure, as an expected mineralogical phase fraction, the `true mineralogical percentage', is available under the assumption of negligible non‐diffracting contents. In order to assess the validity and limitations of the Rietveld‐based approach for cement materials, three commercial samples were measured: (i) white Portland clinker, (ii) grey Portland clinker and (iii) a type‐I grey Portland cement. The samples studied have been chosen in order to cover most of the different typologies of binders. Reproducibilities and general uncertainty values, with a level of confidence of 95%, are reported and discussed.

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Thermal methods and microcalorimetry application in the studies of low energy cements

Cited by 2 publications

References 0 publications

Rietveld quantitative phase analysis with molybdenum radiation

Rietveld quantitative phase analysis with molybdenum radiation

Round robin on Rietveld quantitative phase analysis of Portland cements

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