Title:
Mechanisms of Workability Control in Alkali-Activated Slag by Zinc Addition
Author(s):
Alice Gava, Jean-Baptiste d’Espinose de Lacaillerie, Claire Giraudeau, Loren Jørgensen, Théo Merland, Nicolas Sanson, Marie Teinturier
Publication:
Symposium Paper
Volume:
370
Issue:
Appears on pages(s):
1-10
Keywords:
Admixture, Retarder, Rheology, Sodium silicate, XRD, isothermal calorimetry, SEM
DOI:
10.14359/51751743
Date:
5/1/2026
Abstract:
The retarder effect of zinc (Zn) species on the setting of cementitious binders has been studied in the literature. However, their influence on the rheology of fresh pastes and their chemical fate, in particular in alkali-activated (AA) binders, remains unclear. This study investigates how formulation parameters can affect zinc behaviour in fresh AA binder, aiming to control its retarder effect in order to optimize the material workability and its retention time.
The hydration of cement pastes is a highly complex chemical process that depends on the precursor material and involves interconnected reactions that are modified in the presence of zinc. The effects of zinc have been predominantly reported for OPC-type materials. For low-Ca-content materials, however, such as AA systems (i.e., blast furnace slags), the process is even more complex due to the reactions of zinc moieties with the activator. This work focuses on Zn(II) salt reactions in activated solutions and how they impact yield stress over time by retarding slag hydration. Various fresh zinc-doped alkali-activated paste formulations were examined, resulting in different rheological behaviours. These results contribute to optimizing the use of zinc as a workability agent in AA systems.
Related References:
1. Provis, J. L. Alkali-Activated Materials. Cem. Concr. Res. 2018, 114, 40–48. doi: 10.1016/j.cemconres.2017.02.009
2. Kriven, W. M.; Leonelli, C.; Provis, J. L.; Boccaccini, A. R.; Attwell, C.; Ducman, V. S.; Ferone, C.; Rossignol, S.; Luukkonen, T.; Van Deventer, J. S. J.; Emiliano, J. V.; Lombardi, J. E. Why Geopolymers and Alkali‐activated Materials Are Key Components of a Sustainable World: A Perspective Contribution. J. Am. Ceram. Soc. 2024, 107 (8), 5159–5177. doi: 10.1111/jace.19828
3. Paillard, C.; Cordoba, M. A.; Sanson, N.; d’Espinose De Lacaillerie, J.-B.; Ducouret, G.; Boustingorry, P.; Jachiet, M.; Giraudeau, C.; Kocaba, V. The Role of Solvent Quality and of Competitive Adsorption on the Efficiency of Superplasticizers in Alkali-Activated Slag Pastes. Cem. Concr. Res. 2023, 163, 107020. doi: 10.1016/j.cemconres.2022.107020
4. Tong, S.; Yuqi, Z.; Qiang, W. Recent Advances in Chemical Admixtures for Improving the Workability of Alkali-Activated Slag-Based Material Systems. Constr. Build. Mater. 2021, 272, 121647. doi: 10.1016/j.conbuildmat.2020.121647
5. Xu, L.; Sun, Z.; Chen, Y.; Yang, K.; Yang, X.; Wu, K.; Lothenbach, B. Retardation Mechanism of Zinc on Portland Cement and Alite Hydration. Cem. Concr. Res. 2024, 184, 107571. doi: 10.1016/j.cemconres.2024.107571
6. Holschemacher, K.; Tekle, B. H. Review and Experimental Investigation of Retarder for Alkali-Activated Cement. In Proceedings of the 75th RILEM Annual Week 2021; Escalante-Garcia, J. I., Castro Borges, P., Duran-Herrera, A., Eds.; RILEM Bookseries; Springer International Publishing: Cham, 2023; Vol. 40, pp 614–625. doi: 10.1007/978-3-031-21735-7_67
7. Guo, A.; Zhang, Y.; Feng, H.; Yu, Z.; Fan, C.; Hao, F.; Lu, S.; Ma, H.; Geng, Y.; Sun, Z.; Du, Y. A Review of Setting Retardation Methods for Alkali-Activated Cementitious Materials. J. Mater. Sci. 2025, 60 (31), 13236–13260. doi: 10.1007/s10853-025-11239-0
8. Garg, N.; White, C. E. Mechanism of Zinc Oxide Retardation in Alkali-Activated Materials: An in Situ X-Ray Pair Distribution Function Investigation. J. Mater. Chem. A 2017, 5 (23), 11794–11804. doi: 10.1039/C7TA00412E
9. Tan, J.; Sierens, Z.; Vandevyvere, B.; Dan, H.; Li, J. Zinc Oxide in Alkali-Activated Slag (AAS): Retardation Mechanism, Reaction Kinetics and Immobilization. Constr. Build. Mater. 2023, 371, 130739. doi: 10.1016/j.conbuildmat.2023.130739
10. Cong, X.; Zhou, W.; Geng, X.; Elchalakani, M. Low Field NMR Relaxation as a Probe to Study the Effect of Activators and Retarders on the Alkali-Activated GGBFS Setting Process. Cem. Concr. Compos. 2019, 104, 103399. doi: 10.1016/j.cemconcomp.2019.103399
11. Nedunuri, A. S. S. S.; Muhammad, S. The Role of Zinc Sulphate as a Retarder for Alkali Activated Binders and Its Influence on the Rheological, Setting and Mechanical Behaviour. Constr. Build. Mater. 2022, 344, 128128. doi: 10.1016/j.conbuildmat.2022.128128
12. Qian, G.; Sun, D. D.; Tay, J. H. Characterization of Mercury- and Zinc-Doped Alkali-Activated Slag Matrix. Cem. Concr. Res. 2003, 33 (8), 1257–1262. doi: 10.1016/S0008-8846(03)00046-2