Effect of Alkaline Salts on Calcium Sulfoaluminate Cement Hydration
This work analyzes the effect of the presence of 5 wt.% of solid sodium salts (Na<sub>2</sub>SO<sub>4</sub>, Na<sub>2</sub>CO<sub>3</sub>, and Na<sub>2</sub>SiO<sub>3</sub>) on calcium sulfoaluminate cement (CSA) hydration, addr...
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| Format: | Article |
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MDPI AG
2021-03-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/26/7/1938 |
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| author | Luís Urbano D. Tambara Júnior Janaíde C. Rocha Malik Cheriaf Pilar Padilla-Encinas Ana Fernández-Jiménez Angel Palomo |
| author_facet | Luís Urbano D. Tambara Júnior Janaíde C. Rocha Malik Cheriaf Pilar Padilla-Encinas Ana Fernández-Jiménez Angel Palomo |
| author_sort | Luís Urbano D. Tambara Júnior |
| collection | DOAJ |
| description | This work analyzes the effect of the presence of 5 wt.% of solid sodium salts (Na<sub>2</sub>SO<sub>4</sub>, Na<sub>2</sub>CO<sub>3</sub>, and Na<sub>2</sub>SiO<sub>3</sub>) on calcium sulfoaluminate cement (CSA) hydration, addresses hydration kinetics; 2-, 28-, and 90-d mechanical strength, and reaction product microstructure (with X-ray diffraction (XRD), and Fourier transform infrared spectroscopy, (FTIR). The findings show that the anions affect primarily the reactions involved. Ettringite and AH<sub>3</sub>, are the majority hydration products, while monosulfates are absent in all of the samples. All three salts hasten CSA hydration and raise the amount of ettringite formed. Na<sub>2</sub>SO<sub>4</sub> induces cracking in the ≥28-d pastes due to post-hardening gypsum and ettringite formation from the excess SO<sub>4</sub><sup>2–</sup> present. Anhydrite dissolves more rapidly in the presence of Na<sub>2</sub>CO<sub>3</sub>, prompting carbonation. Na<sub>2</sub>SiO<sub>3</sub> raises compressive strength and exhibits strätlingite as one of its reaction products. |
| first_indexed | 2024-03-10T12:46:41Z |
| format | Article |
| id | doaj.art-9894187dc11d4be6ba81d57c3291b704 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T12:46:41Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-9894187dc11d4be6ba81d57c3291b7042023-11-21T13:25:52ZengMDPI AGMolecules1420-30492021-03-01267193810.3390/molecules26071938Effect of Alkaline Salts on Calcium Sulfoaluminate Cement HydrationLuís Urbano D. Tambara Júnior0Janaíde C. Rocha1Malik Cheriaf2Pilar Padilla-Encinas3Ana Fernández-Jiménez4Angel Palomo5Laboratory of Waste Valorization and Sustainable Materials (ValoRes), Department of Civil Engineering, Federal University of Santa Catarina (UFSC), Florianópolis 88040900, BrazilLaboratory of Waste Valorization and Sustainable Materials (ValoRes), Department of Civil Engineering, Federal University of Santa Catarina (UFSC), Florianópolis 88040900, BrazilLaboratory of Waste Valorization and Sustainable Materials (ValoRes), Department of Civil Engineering, Federal University of Santa Catarina (UFSC), Florianópolis 88040900, BrazilEduardo Torroja Institute, National Research Council (CSIC), 28033 Madrid, SpainEduardo Torroja Institute, National Research Council (CSIC), 28033 Madrid, SpainEduardo Torroja Institute, National Research Council (CSIC), 28033 Madrid, SpainThis work analyzes the effect of the presence of 5 wt.% of solid sodium salts (Na<sub>2</sub>SO<sub>4</sub>, Na<sub>2</sub>CO<sub>3</sub>, and Na<sub>2</sub>SiO<sub>3</sub>) on calcium sulfoaluminate cement (CSA) hydration, addresses hydration kinetics; 2-, 28-, and 90-d mechanical strength, and reaction product microstructure (with X-ray diffraction (XRD), and Fourier transform infrared spectroscopy, (FTIR). The findings show that the anions affect primarily the reactions involved. Ettringite and AH<sub>3</sub>, are the majority hydration products, while monosulfates are absent in all of the samples. All three salts hasten CSA hydration and raise the amount of ettringite formed. Na<sub>2</sub>SO<sub>4</sub> induces cracking in the ≥28-d pastes due to post-hardening gypsum and ettringite formation from the excess SO<sub>4</sub><sup>2–</sup> present. Anhydrite dissolves more rapidly in the presence of Na<sub>2</sub>CO<sub>3</sub>, prompting carbonation. Na<sub>2</sub>SiO<sub>3</sub> raises compressive strength and exhibits strätlingite as one of its reaction products.https://www.mdpi.com/1420-3049/26/7/1938calcium sulfoaluminate cementalkaline saltsmicrostructureettringite |
| spellingShingle | Luís Urbano D. Tambara Júnior Janaíde C. Rocha Malik Cheriaf Pilar Padilla-Encinas Ana Fernández-Jiménez Angel Palomo Effect of Alkaline Salts on Calcium Sulfoaluminate Cement Hydration Molecules calcium sulfoaluminate cement alkaline salts microstructure ettringite |
| title | Effect of Alkaline Salts on Calcium Sulfoaluminate Cement Hydration |
| title_full | Effect of Alkaline Salts on Calcium Sulfoaluminate Cement Hydration |
| title_fullStr | Effect of Alkaline Salts on Calcium Sulfoaluminate Cement Hydration |
| title_full_unstemmed | Effect of Alkaline Salts on Calcium Sulfoaluminate Cement Hydration |
| title_short | Effect of Alkaline Salts on Calcium Sulfoaluminate Cement Hydration |
| title_sort | effect of alkaline salts on calcium sulfoaluminate cement hydration |
| topic | calcium sulfoaluminate cement alkaline salts microstructure ettringite |
| url | https://www.mdpi.com/1420-3049/26/7/1938 |
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