Fundamental Discrepancy of Chemical Reactivity of Tricalcium Oxy Silicate , and Their Polymorphs: A Density Functional Theory Study

Tricalcium oxy silicate (C.sub.3S) and dicalcium silicate (C.sub.2S) are the major constituents of cement. In this study, the reactivity of polymorphs of calcium silicates is quantitatively investigated using Density Functional Theory. The result of combining the DFT calculation and the Bader charge...

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Bibliographic Details
Published in:International journal of concrete structures and materials 2022-12, Vol.16 (1)
Main Authors: Kim, Seungchan, Lee, Yangwoo, Plank, J, Moon, Juhyuk
Format: Article
Language:English
Subjects:
Comparative analysis
Density functionals
Specific gravity
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Summary:Tricalcium oxy silicate (C.sub.3S) and dicalcium silicate (C.sub.2S) are the major constituents of cement. In this study, the reactivity of polymorphs of calcium silicates is quantitatively investigated using Density Functional Theory. The result of combining the DFT calculation and the Bader charge analysis elucidates that the main difference in reactivity between C.sub.3S and C.sub.2S is the presence of oxy ions in C.sub.3S which has smaller partial charge compared to that of other oxygen in the crystals. For the C.sub.3S, the reactivity of among different C.sub.3S polymorphs is decisively affected by the Bader charge of oxy ions. In contrast, total internal energy of C.sub.2S determines the quantitative chemical reactivity of C.sub.2S polymorphs. This result suggests that oxy ion has more dominant impact on the thermodynamic stability of calcium silicates. Furthermore, total energy can be used to estimate the chemical reactivity of calcium silicates, where there is no oxy ion exists.
ISSN:1976-0485
DOI:10.1186/s40069-022-00539-3