Rheological behaviour and reaction kinetics in alkali-activated slag-metakaolin blends with limestone sludge
DOI:
https://doi.org/10.14311/AP.2026.66.0185Keywords:
limestone sludge, limestone powder, alkali activation, rheology, early-stage reaction kineticsAbstract
This study focuses on the influence of raw limestone materials on the fresh-state properties and early hydration behaviour of alkali-activated systems composed of blast furnace slag and metakaolin. Three types of limestone powders were examined in relation to their rheological impact, structural rebuilding (via oscillatory strain-amplitude sweeps and 3iTT tests), calorimetric behaviour, and thermal stability (TG/DTG). The results show that, at early stages, limestone primarily acts as an inert filler, but its particle morphology and impurity content significantly affect the system’s rheology and reaction kinetics. Limestone powder with high calcite content slightly accelerates structural regeneration and improves dispersion, while limestone powders containing clay minerals increase plasticity and stiffness due to water retention and enhanced interparticle interactions. Such clay-bearing powders can, however, also slow structural rebuilding and reduce flowability under shear. Calorimetry and thermal analysis confirmed that limestone powder addition, especially in low-calcium systems, promoted the formation of hybrid gels (C-(A)-S-H and N-A-S-H). Clay-related alumina also significantly affected both the early-age rheology and the reaction kinetics.
Downloads
References
[1] A. M. Rashad. Effect of limestone powder on the properties of alkali-activated materials – A critical overview. Construction and Building Materials 356:129188, 2022. https://doi.org/10.1016/j.conbuildmat.2022.129188
[2] X. Zhu, X. Kang, J. Deng, et al. Chemical and physical effects of high-volume limestone powder on sodium silicate-activated slag cement (AASC). Construction and Building Materials 292:123257, 2021. https://doi.org/10.1016/j.conbuildmat.2021.123257
[3] X. Gao, Q. L. Yu, H. J. H. Brouwers. Properties of alkali activated slag-fly ash blends with limestone addition. Cement and Concrete Composites 59(1):119–128, 2015. https://doi.org/10.1016/j.cemconcomp.2015.01.007
[4] P. Perez-Cortes, J. I. Escalante-Garcia. Design and optimization of alkaline binders of limestone-metakaolin – A comparison of strength, microstructure and sustainability with portland cement and geopolymers. Journal of Cleaner Production 273:123118, 2020. https://doi.org/10.1016/j.jclepro.2020.123118
[5] J. Qian, M. Song. Study on influence of limestone powder on the fresh and hardened properties of early age metakaolin based geopolymer. In K. Scrivener, A. Favier (eds.), Calcined Clays for Sustainable Concrete, vol. 10, pp. 253–259. Springer Netherlands, Dordrecht, 2015. https://doi.org/10.1007/978-94-017-9939-3_31
[6] C. K. Yip, J. L. Provis, G. C. Lukey, J. S. J. van Deventer. Carbonate mineral addition to metakaolin-based geopolymers. Cement and Concrete Composites 30(10):979–985, 2008. https://doi.org/10.1016/j.cemconcomp.2008.07.004
[7] C. Lin Chan, M. Zhang. Effect of limestone on engineering properties of alkali-activated concrete: A review. Construction and Building Materials 362:129709, 2023. https://doi.org/10.1016/j.conbuildmat.2022.129709
[8] B. Felekoğlu, K. Tosun, B. Baradan, et al. The effect of fly ash and limestone fillers on the viscosity and compressive strength of self-compacting repair mortars. Cement and Concrete Research 36(9):1719–1726, 2006. https://doi.org/10.1016/j.cemconres.2006.04.002
[9] N. R. Rakhimova, R. Z. Rakhimov, N. I. Naumkina, et al. Influence of limestone content, fineness, and composition on the properties and microstructure of alkali-activated slag cement. Cement and Concrete Composites 72:268–274, 2016. https://doi.org/10.1016/j.cemconcomp.2016.06.015
[10] J. Xiang, L. Liu, X. Cui, et al. Effect of limestone on rheological, shrinkage and mechanical properties of alkali – Activated slag/fly ash grouting materials. Construction and Building Materials 191:1285–1292, 2018. https://doi.org/10.1016/j.conbuildmat.2018.09.209
[11] X. Dai, S. Aydin, M. Y. Yardimci, et al. Rheology, early-age hydration and microstructure of alkaliactivated GGBFS-fly ash-limestone mixtures. Cement and Concrete Composites 124:104244, 2021. https://doi.org/10.1016/j.cemconcomp.2021.104244
[12] H. Mehdizadeh, E. Najafi Kani. Rheology and apparent activation energy of alkali activated phosphorous slag. Construction and Building Materials 171:197–204, 2018. https://doi.org/10.1016/j.conbuildmat.2018.03.130
[13] V. Bilek Jr, M. Pazour. Structural build-up and breakdown of sodium hydroxide-activated slag paste assessed using oscillatory rheology. Journal of Physics: Conference Series 2341(1):012001, 2022. https://doi.org/10.1088/1742-6596/2341/1/012001
[14] D. Jiao, R. De Schryver, C. Shi, G. De Schutter. Thixotropic structural build-up of cement-based materials: A state-of-the-art review. Cement and Concrete Composites 122:104152, 2021. https://doi.org/10.1016/j.cemconcomp.2021.104152
[15] A. M. Mostafa, A. Yahia. New approach to assess build-up of cement-based suspensions. Cement and Concrete Research 85:174–182, 2016. https://doi.org/10.1016/j.cemconres.2016.03.005
[16] X. Dai, S. Aydin, M. Y. Yardimci, G. De Schutter. Rheology and structural build-up of sodium silicate- and sodium hydroxide-activated GGBFS mixtures. Cement and Concrete Composites 131:104570, 2022. https://doi.org/10.1016/j.cemconcomp.2022.104570
[17] D. Kubátová, I. Khongová, M. Krejčí Kotlánová, et al. The use of limestone sludge for the geopolymer preparation. IOP Conference Series: Materials Science and Engineering 1205(1):012002, 2021. https://doi.org/10.1088/1757-899X/1205/1/012002
[18] B. Panda, C. Unluer, M. J. Tan. Investigation of the rheology and strength of geopolymer mixtures for extrusion-based 3D printing. Cement and Concrete Composites 94:307–314, 2018. https://doi.org/10.1016/j.cemconcomp.2018.10.002
[19] M. Stieger. The rheology handbook – For users of rotational and oscillatory rheometers. Applied Rheology 12(5):232–232, 2002. https://doi.org/doi:10.1515/arh-2002-0029
[20] B. Panda, G. B. Singh, C. Unluer, M. J. Tan. Synthesis and characterization of one-part geopolymers for extrusion based 3D concrete printing. Journal of Cleaner Production 220:610–619, 2019. https://doi.org/10.1016/j.jclepro.2019.02.185
[21] P. Rovnaník, P. Rovnaníková, M. Vyšvařil, et al. Rheological properties and microstructure of binary waste red brick powder/metakaolin geopolymer. Construction and Building Materials 188:924–933, 2018. https://doi.org/10.1016/j.conbuildmat.2018.08.150
[22] S. A. Bernal, J. L. Provis, V. Rose, R. Mejia De Gutierrez. Evolution of binder structure in sodium silicate-activated slag-metakaolin blends. Cement and Concrete Composites 33(1):46–54, 2011. https://doi.org/10.1016/j.cemconcomp.2010.09.004
[23] M. Palacios, S. Gismera, M. M. Alonso, et al. Early reactivity of sodium silicate-activated slag pastes and its impact on rheological properties. Cement and Concrete Research 140:106302, 2021. https://doi.org/10.1016/j.cemconres.2020.106302
[24] Y. Liu, B. Dong, Y. Zhang, et al. Limestone powder-based alkali-activated materials: Influence of activator type. Powder Technology 434:119334, 2024. https://doi.org/10.1016/j.powtec.2023.119334
[25] F. J. Huertas, L. Chou, R. Wollast. Mechanism of kaolinite dissolution at room temperature and pressure Part II: Kinetic study. Geochimica et Cosmochimica Acta 63(19–20):3261–3275, 1999. https://doi.org/10.1016/S0016-7037(99)00249-5
[26] R. Mohamed, R. Abd Razak, M. M. A. B. Abdullah, et al. Heat evolution of alkali-activated materials: A review on influence factors. Construction and Building Materials 314:125651, 2022. https://doi.org/10.1016/j.conbuildmat.2021.125651
[27] U. De Filippis, E. Prud’homme, S. Meille. Raw earth stabilised by alkaline activation of slag: Effect of clay on slag hydration. Materialia 36:102143, 2024. https://doi.org/10.1016/j.mtla.2024.102143
[28] A. Chaipanich, K. Wianglor, M. Piyaworapaiboon, S. Sinthupinyo. Thermogravimetric analysis and microstructure of alkali-activated metakaolin cement pastes. Journal of Thermal Analysis and Calorimetry 138(3):1965–1970, 2019. https://doi.org/10.1007/s10973-019-08592-z
[29] A. Cwirzen, J. L. Provis, V. Penttala, K. Habermehl-Cwirzen. The effect of limestone on sodium hydroxideactivated metakaolin-based geopolymers. Construction and Building Materials 66:53–62, 2014. https://doi.org/10.1016/j.conbuildmat.2014.05.022
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Dana Kubátová, Eliška Křivánková, Michaela Krejčí Kotlánová, Martin Nguyen, Martin Boháč
This work is licensed under a Creative Commons Attribution 4.0 International License.
