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The superstructure of C3S from synchrotron and neutron powder diffraction and its role in quantitative phase analyses
We have synthesised the room temperature MIII form of alite stabilised by doping with Mg and Al. The complex disordered superstructure of this tricalcium silicate (Ca3SiO5 (C3 S)) sample has been studied by a joint Rietveld refinement of ultra-high-resolution synchrotron X-ray powder diffraction data, medium-resolution neutron powder diffraction data and soft constraints of interatomic distances. Alite crystallises in a monoclinic cell with dimensions a = 33.1078(6) A, b = 7.0355(1) A, c = 18.5211(4) A, beta = 94.137(1) degree and V = 4302.9(2) A3. The final R factors were RWP = 8.76% and RF(C3S) = 3.45% for the synchrotron data and RWP = 6.09% and RF(C3S) = 5.10% for the neutron data. The reported superstructure is simpler than those previously reported, and it fits properly to a variety of Portland clinker and cement patterns. The Rietveld analyses of four clinkers with variable Mg contents have shown that the refinements are good. The Bogue approach gave quite poor results when compared to these state-of-the-art powder diffraction analyses. Bogue method slightly underestimates the C3S+C2S content, overestimates the C3A fraction and underestimates the C4AF content. Similar analyses of Portland cements with nine crystalline phases are shown to be feasible.
The superstructure of C3S from synchrotron and neutron powder diffraction and its role in quantitative phase analyses
We have synthesised the room temperature MIII form of alite stabilised by doping with Mg and Al. The complex disordered superstructure of this tricalcium silicate (Ca3SiO5 (C3 S)) sample has been studied by a joint Rietveld refinement of ultra-high-resolution synchrotron X-ray powder diffraction data, medium-resolution neutron powder diffraction data and soft constraints of interatomic distances. Alite crystallises in a monoclinic cell with dimensions a = 33.1078(6) A, b = 7.0355(1) A, c = 18.5211(4) A, beta = 94.137(1) degree and V = 4302.9(2) A3. The final R factors were RWP = 8.76% and RF(C3S) = 3.45% for the synchrotron data and RWP = 6.09% and RF(C3S) = 5.10% for the neutron data. The reported superstructure is simpler than those previously reported, and it fits properly to a variety of Portland clinker and cement patterns. The Rietveld analyses of four clinkers with variable Mg contents have shown that the refinements are good. The Bogue approach gave quite poor results when compared to these state-of-the-art powder diffraction analyses. Bogue method slightly underestimates the C3S+C2S content, overestimates the C3A fraction and underestimates the C4AF content. Similar analyses of Portland cements with nine crystalline phases are shown to be feasible.
The superstructure of C3S from synchrotron and neutron powder diffraction and its role in quantitative phase analyses
De La Torre, A.G. (Autor:in) / Bruque, S. (Autor:in) / Campo, J. (Autor:in) / Aranda, M.A.G. (Autor:in)
Cement and Concrete Research ; 32 ; 1347-1356
2002
10 Seiten, 48 Quellen
Aufsatz (Zeitschrift)
Englisch
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