ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Geopolymerization, rheology, and strength development of metakaolin-based self-compacting geopolymer concrete

Shahida Khan, Malik Parveez, and Manzoor Ahmad Tantray

Department of Chemical Engineering, National Institute of Technology, Srinagar, India

E-mail: Shaibakhan321@gmail.com

Received: 17 April 2025  Accepted: 1 September 2025

Abstract:

This study examines the fresh and hardened properties of self-compacting geopolymer concrete (SCGC) produced using metakaolin as the only binder. The work focuses on optimizing key mix design variables—alkali concentration, sodium silicate-to-hydroxide ratio, superplasticizer content, and extra water—under ambient curing. Unlike many earlier investigations that rely on blended binders or heat curing, this research evaluates a metakaolin-based SCGC. The novelty of the work lies in combining self-compacting behavior with a single-binder geopolymer system cured at room temperature (27 ± 2 °C) for structural applications, an approach rarely explored in existing literature. The SCGC displayed excellent workability, achieving slump flows up to about 740 mm without signs of segregation. Compressive strengths above 40 MPa and tensile strengths up to 3.6 MPa at 28 days were recorded for well-balanced mixtures. Results suggest that moderate alkalinity (12 M NaOH with a silicate-to-hydroxide ratio near 2.1–3.0) provides the best balance of flowability and strength, while very high alkali levels reduced performance. The improved behavior is linked to uniform gel formation and stable rheology within the binder system. Overall, the findings confirm that metakaolin-based SCGC can be produced successfully without Portland cement and without heat curing. Its combination of high flow, reliable strength, and potentially lower carbon footprint makes it a promising alternative for sustainable construction of reinforced concrete structures.

Keywords: Self-compacting geopolymer concrete; Metakaolin; Workability; Mechanical properties

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04499-2

Chemical Papers 80 (2) 1931–1945 (2026)