Properties and Microstructure of Alkali-Activated Slag Paste Modified by Superabsorbent Polymers
Publication: Journal of Materials in Civil Engineering
Volume 36, Issue 5
Abstract
Superabsorbent polymers (SAPs) can serve as effective internal curing agents in alkali-activated slag (AAS) systems, mitigating the risk of cracking. However, the influence of SAPs on the properties and microstructure of AAS systems is not yet fully understood. In this study, the effects of SAPs on the properties, reaction products, and internal moisture migration of AAS pastes were investigated. The water released by SAPs during curing supplemented the water consumption in the hydration process, maintained internal relative humidity, and reduced autogenous shrinkage by more than 80%. However, the addition of SAPs not only created voids in the hardened paste, as indicated by the mercury intrusion porosimetry (MIP) results, but also increased the microscopic pore volume of the paste. SAPs did not change the phase composition of AAS hydration products, but increased the differential thermogravimetry (DTG) peak corresponding to the main hydration product C(-A)-S-H gel at 28 days. The increase in chemically bound water in AAS pastes containing SAPs, along with the changes in the transverse relaxation time () peak area corresponding to SAPs in the low-field NMR results, likely are due to the gradual release of water during internal curing by SAPs.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
This work was funded by the National Natural Science Foundation of China (Grant No. 52278272).
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Published In
Journal of Materials in Civil Engineering
Volume 36 • Issue 5 • May 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: Jun 11, 2023
Accepted: Oct 27, 2023
Published online: Feb 23, 2024
Published in print: May 1, 2024
Discussion open until: Jul 23, 2024
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