Autogenous and drying shrinkage of alkali‐activated slag mortars. Issue 8 (25th February 2019)

• Record Type: Journal Article
• Authors: Hu, Xiang; Shi, Caijun; Zhang, Zuhua; Hu, Zhangli
• Is Part Of: Journal of the American Ceramic Society. Volume 102:Issue 8(2019)
• Page Start: 4963
• Page End: 4975
• Publication Date: 2019-02-25
• Subjects: additives -- alkali activation -- alkali‐activated slag -- shrinkage; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.16349
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract: Shrinkage of alkali‐activated slag (AAS) cement is a critical issue for its industrial application. This study investigated the mechanisms and effectiveness of shrinkage‐reducing agent (SRA) and magnesia expansive agent on reducing autogenous and drying shrinkage of AAS mortars that were activated by liquid sodium silicate (LSS) solution with modulus (SiO2 /Na2 O molar ratio) of 0‐1.5. The results showed that the autogenous shrinkage of AAS mortars increased with the increase of LSS modulus from 0 to 0.5, then decreased as modulus increased up to 1.5. The drying shrinkage consistently increased with the increase in the modulus of LSS. The oxyalkylene alcohol‐based SRA could significantly reduce the autogenous and drying shrinkage of AAS mortars while the magnesia expensive agent was comparatively less effective. The autogenous shrinkage of AAS mortars was inversely proportional to the internal relative humidity, while the drying shrinkage was more related to the mass loss of samples. Mathematical models were established to describe the autogenous and drying shrinkage behavior of AAS mortars.