Abstract

Alkali-activated materials have emerged as promising low-carbon alternatives to ordinary Portland cement-based binders; however, their practical application is strictly limited by rapid setting and poor workability. To address these challenges, this study proposes an evaluation methodology combining setting time measurement, cloud point tests for chemical stability, and wide-range rheological analysis. While conventional superplasticizers like polycarboxylate ether (PCE) proved unstable in high-alkaline environments, cloud point tests revealed that polynaphthalene sulfonate (PNS) and butyl acrylate (BA) exhibited superior chemical stability. Notably, BA was identified as a novel and effective dispersant in 3.5 M KOH-activated systems, reducing yield stress of fresh mortar by 33% when combined with an anti-foaming agent. In terms of retardation, 0.06% sodium gluconate (SG) successfully extended the initial setting time to over 5 h. Furthermore, rheological modeling revealed that replacing 10% of ground granulated blast-furnace slag with fly ash not only reduced viscosity but also enhanced the 28-day compressive strength to 45.0 MPa, surpassing the control sample (43.7 MPa) due to improved particle packing. These findings offer practical guidelines for enhancing the workability of alkali-activated slag mortars through the use of chemically stable admixtures and optimized mineral substitution.

Department(s)

Civil, Architectural and Environmental Engineering

Publication Status

Full Text Access

Keywords and Phrases

Alkali-activated slag; Chemical stability; Dispersant; Retarder; Rheology

International Standard Serial Number (ISSN)

2352-7102

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 Elsevier, All rights reserved.

Publication Date

15 Feb 2026

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