Abstract
Superabsorbent polymer (SAP) has been commonly used to mitigate the shrinkage of alkali-activated slag (AAS) pastes through internal curing. However, the effectiveness of internal curing might be affected by the microstructure of the pastes. Therefore, the effects of incorporating limestone powder (LP) on the microstructure and shrinkage of AAS pastes containing SAP are studied. The results reveal that incorporating LP mitigates the autogenous shrinkage of the pastes with SAP. This is because the incorporation of LP reduces the fraction of mesopores in the pastes containing SAP, while adding SAP maintains the internal relative humidity and increases the size of minimum pores that can drive autogenous shrinkage. In contrast, adding LP tends to enhance the driving force of autogenous shrinkage in the pastes without SAP due to the conversion of mesopores to gel pores. Furthermore, incorporating LP simultaneously enhances the reaction and generates more macropores in the pastes, causing a negligible influence on their mechanical properties and an increase of drying shrinkage. Overall, incorporating LP promotes the internal curing effectiveness in decreasing the autogenous shrinkage of the pastes.
| Original language | English |
|---|---|
| Article number | 107243 |
| Number of pages | 14 |
| Journal | Journal of Building Engineering |
| Volume | 76 |
| Early online date | 1 Jul 2023 |
| DOIs | |
| Publication status | Published - 1 Oct 2023 |
Bibliographical note
Acknowledgment:The authors wish to acknowledge the financial support from Zhejiang Provincial Key R&D Programme (No.: 2023C03146), and Ningbo Municipal Bureau of Science and Technology under Commonweal Programme (No.: 2022S177), and Zhejiang Provincial Key Laboratory for Carbonaceous Wastes Processing and Process Intensification Research funded by the Zhejiang Provincial Department of Science and Technology (2020E10018).
Keywords
- Limestone powder
- Alkali-activated slag
- Internal curing
- Superabsorbent polymer
- Autogenous shrinkage