1. Hydration mechanism of calcium sulfoaluminate-activated supersulfated cement.
- Author
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Sun, Zhengning, Nie, Song, Zhou, Jian, Li, Hui, Chen, Zhifeng, Xu, Mingfeng, Mu, Ru, and Wang, Ying
- Subjects
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SULFOALUMINATE cement , *CARBON emissions , *PORTLAND cement , *CEMENT , *CALCIUM , *ETTRINGITE - Abstract
Innovations in the cement industry strive towards achieving an eco-friendly alternative to traditional cement. A low-carbon cement, calcium sulfoaluminate-activated supersulfated cement (CSA-SSC), has been recently developed. This cement consists of 80% granulated blastfurnace slag (GBFS), 15% anhydrite, and 5% high-belite calcium sulfoaluminate cement (HB-CSA) clinker. The hydration mechanism of CSA-SSC was experimentally investigated using isothermal calorimetry, X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy, and was numerically studied using thermodynamic modeling. CSA-SSC shows a moderate compressive strength at the early stage, which is mainly attributed to the rapid formation of ettringite from the hydration of C 4 A 3 S ¯ with CaSO 4 in HB-CSA clinker. Meanwhile, the hydration of f-CaO in HB-CSA clinker supplies an alkaline environment for the dissolution of GBFS and the formation of more ettringite. In the late stage, apart from ettringite, the hydration of GBFS forms C–S–H, leading to the continuous increase in late strength. A statistical analysis reveals that the high volume of GBFS in CSA-SSC results in a very low direct CO 2 emission, which is only 8.7% of that of Portland cement. [Display omitted] • CSA-SSC is comprised of 80% GBFS, 15% anhydrite and 5% HB-CSA clinker. • The carbon dioxide emission of CSA-SSC is 72.0 kg/t, 8.7% of that of PC. • CSA-SSC shows relatively higher compressive strength than PC and other types of SSCs. • The hydration of CSA-SSC produces ettringite from beginning and C–S–H at later stage. • CSA-SSC has a high ratio of compressive strength to amount of non-evaporable water. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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