Physicochemical Study of the Self-Disintegration of Calcium Orthosilicate (β→γ) in the Presence of the C<sub>12</sub>A<sub>7</sub> Aluminate Phase
The β-γ polymorphic transition of calcium orthosilicate (C<sub>2</sub>S) is a key phenomenon in cement chemistry. During this transition, the compound expands due to structural changes and a significant reduction in its density is observed, leading to its disintegration into a powder wit...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | article |
| Language: | EN |
| Published: |
MDPI AG
2021
|
| Subjects: | |
| Online Access: | https://doaj.org/article/55a3d9aa88e64d05b71925daf849e1db |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | The β-γ polymorphic transition of calcium orthosilicate (C<sub>2</sub>S) is a key phenomenon in cement chemistry. During this transition, the compound expands due to structural changes and a significant reduction in its density is observed, leading to its disintegration into a powder with a very high specific surface area. Owing to this tendency of the C<sub>2</sub>S material to “self-disintegrate”, its production is energy-efficient and thus environmentally friendly. A physicochemical study of the self-disintegration process was conducted with the aim of determining how the amount of dodecacalcium hepta-aluminate (C<sub>12</sub>A<sub>7</sub>) in calcium orthosilicate (C<sub>2</sub>S) affects the temperature at which the polymorphic transi-tions from α’L-C<sub>2</sub>S to β-C<sub>2</sub>S and from β-C<sub>2</sub>S to γ-C<sub>2</sub>S undergo stabilization. The applied techniques included differential thermal analysis (DTA), calorimetry and X-ray diffraction (XRD), and they made it possible to determine what C<sub>2</sub>S/C<sub>12</sub>A<sub>7</sub> phase ratio in the samples and what cooling rate constitute the optimal conditions of the self-disintegration process. The optimal cooling rate for C<sub>2</sub>S materials with a C<sub>12</sub>A<sub>7</sub> content of up to 60 wt% was determined to be 5 K·min<sup>−1</sup>. The optimal mass ratio of C<sub>2</sub>S/C<sub>12</sub>A<sub>7</sub> was found to be 70/30, which ensures both efficient self-disintegration and desirable grain size distribution. |
|---|