In Situ Spectroscopic Insights into the Setting Performance of Alkali-Activated Slag
Publication: Journal of Materials in Civil Engineering
Volume 35, Issue 2
Abstract
This work investigated the setting performance of alkali-activated slag (AAS) pastes prepared with various activators including sodium hydroxide (NH), sodium carbonate/hydroxide (Nc/NH), and sodium silicate (NS) solutions using in situ attenuated total reflectance Fourier transform infrared spectroscopy (FTIR). Also, the AAS slurry samples at the initial and final setting moments were characterized by multiple microscopic techniques [i.e., X-ray diffraction (XRD), thermogravimetric analysis (TGA), FTIR, and field emission scanning electron microscopy (FESEM)]. The results showed that a higher concentration of NH activator leads to more rapid setting reaction and more calcium-aluminosilicate-hydrate (C─ A─ S─ H) formation in AAS at the setting moments. In AAS prepared with carbonate-rich activators, early-age precipitation of carbonate phases (e.g., gaylussite and calcite) contributed substantially to the initial setting completion; afterward, the C─ A─ S─ H precipitation played a decisive role in final setting realization. In NS-activated slag systems, a relatively high silica modulus in activators facilitated the plasticity loss of fluid paste due to the early precipitation of C─ A─ S─ H products formed by the rapid reaction of aqueous silicates from activators with the calcium ions released from dissolving slag particles. This study contributes to identification of characteristic molecular and microstructural features of AAS that are correlated well with the setting moments.
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Data Availability Statement
All data, models, and code generated or used during the study appear in the published article.
Acknowledgments
The financial support from the University of Hong Kong through the URC Small Equipment Grant and Seed Fund for Basic Research is greatly appreciated.
References
Akturk, B., A. H. Akca, and A. B. Kizilkanat. 2020. “Fracture response of fiber-reinforced sodium carbonate activated slag mortars.” Constr. Build. Mater. 241 (11): 118128. https://doi.org/10.1016/j.conbuildmat.2020.118128.
ASTM. 2021. Standard test methods for time of setting of hydraulic cement by vicat needle. ASTM C191. West Conshohocken, PA: ASTM.
Aydın, S., and B. Baradan. 2014. “Effect of activator type and content on properties of alkali-activated slag mortars.” Composites, Part B 57 (Oct): 166–172. https://doi.org/10.1016/j.compositesb.2013.10.001.
Ben Haha, M., G. Le Saout, F. Winnefeld, and B. Lothenbach. 2011. “Influence of activator type on hydration kinetics, hydrate assemblage and microstructural development of alkali activated blast-furnace slags.” Cem. Concr. Res. 41 (3): 301–310. https://doi.org/10.1016/j.cemconres.2010.11.016.
Bernal, S. A., J. L. Provis, R. J. Myers, R. San Nicolas, and J. S. J. van Deventer. 2015. “Role of carbonates in the chemical evolution of sodium carbonate-activated slag binders.” Mater. Struct. 48 (3): 517–529. https://doi.org/10.1617/s11527-014-0412-6.
Cai, R., and H. Ye. 2021. “Clinkerless ultra-high strength concrete based on alkali-activated slag at high temperatures.” Cem. Concr. Res. 145 (21): 106465. https://doi.org/10.1016/j.cemconres.2021.106465.
Cao, R., S. Zhang, N. Banthia, Y. Zhang, and Z. Zhang. 2020. “Interpreting the early-age reaction process of alkali-activated slag by using combined embedded ultrasonic measurement, thermal analysis, XRD, FTIR and SEM.” Composites, Part B 186 (20): 107840. https://doi.org/10.1016/j.compositesb.2020.107840.
Chang, J. J. 2003. “A study on the setting characteristics of sodium silicate-activated slag pastes.” Cem. Concr. Res. 33 (7): 1005–1011. https://doi.org/10.1016/S0008-8846(02)01096-7.
Chang, J. J., W. Yeih, and C. C. Hung. 2005. “Effects of gypsum and phosphoric acid on the properties of sodium silicate-based alkali-activated slag pastes.” Cem. Concr. Compos. 27 (1): 85–91. https://doi.org/10.1016/j.cemconcomp.2003.12.001.
Chen, Z., and H. Ye. 2021. “Sequestration and release of nitrite and nitrate in alkali-activated slag: A route toward smart corrosion control.” Cem. Concr. Res. 143 (Feb): 106398. https://doi.org/10.1016/j.cemconres.2021.106398.
Choi, S., and K.-M. Lee. 2019. “Influence of Na2O content and Ms (SiO2/Na2O) of alkaline activator on workability and setting of alkali-activated slag paste.” Materials 12 (13): 2072. https://doi.org/10.3390/ma12132072.
Deb, P. S., P. Nath, and P. K. Sarker. 2014. “The effects of ground granulated blast-furnace slag blending with fly ash and activator content on the workability and strength properties of geopolymer concrete cured at ambient temperature.” Mater. Des. 62 (1): 32–39. https://doi.org/10.1016/j.matdes.2014.05.001.
De Schutter, G., and L. Taerwe. 1995. “General hydration model for portland cement and blast furnace slag cement.” Cem. Concr. Res. 25 (3): 593–604. https://doi.org/10.1016/0008-8846(95)00048-H.
Dung, N. T., T. J. N. Hooper, and C. Unluer. 2019. “Accelerating the reaction kinetics and improving the performance of Na2CO3-activated GGBS mixes.” Cem. Concr. Res. 126 (1): 105927. https://doi.org/10.1016/j.cemconres.2019.105927.
Fang, S., E. S. S. Lam, B. Li, and B. Wu. 2020. “Effect of alkali contents, moduli and curing time on engineering properties of alkali activated slag.” Constr. Build. Mater. 249 (Apr): 118799. https://doi.org/10.1016/j.conbuildmat.2020.118799.
Fernández-Jiménez, A., and F. Puertas. 2001. “Setting of alkali-activated slag cement. Influence of activator nature.” Adv. Cem. Res. 13 (3): 115–121. https://doi.org/10.1680/adcr.2001.13.3.115.
García-Lodeiro, I., A. Fernández-Jiménez, M. T. Blanco, and A. Palomo. 2008. “FTIR study of the sol–gel synthesis of cementitious gels: C–S–H and N–A–S–H.” J. Sol-Gel Sci. Technol. 45 (1): 63–72. https://doi.org/10.1007/s10971-007-1643-6.
Hojati, M., and A. Radlińska. 2017. “Shrinkage and strength development of alkali-activated fly ash-slag binary cements.” Constr. Build. Mater. 150 (Jun): 808–816. https://doi.org/10.1016/j.conbuildmat.2017.06.040.
Huang, L., J.-C. Liu, R. Cai, and H. Ye. 2021. “Mechanical degradation of ultra-high strength alkali-activated concrete subjected to repeated loading and elevated temperatures.” Cem. Concr. Compos. 121 (10): 104083. https://doi.org/10.1016/j.cemconcomp.2021.104083.
Jiang, M., X. Chen, F. Rajabipour, and C. T. Hendrickson. 2014. “Comparative life cycle assessment of conventional, glass powder, and alkali-activated slag concrete and mortar.” J. Infrastruct. Syst. 20 (4): 04014020. https://doi.org/10.1061/(ASCE)IS.1943-555X.0000211.
Jiao, Z., Y. Wang, W. Zheng, and W. Huang. 2018. “Effect of dosage of sodium carbonate on the strength and drying shrinkage of sodium hydroxide based alkali-activated slag paste.” Constr. Build. Mater. 179 (Mar): 11–24. https://doi.org/10.1016/j.conbuildmat.2018.05.194.
Kovtun, M., E. P. Kearsley, and J. Shekhovtsova. 2015. “Chemical acceleration of a neutral granulated blast-furnace slag activated by sodium carbonate.” Cem. Concr. Res. 72 (Feb): 1–9. https://doi.org/10.1016/j.cemconres.2015.02.014.
Król, M., P. Rożek, D. Chlebda, and W. Mozgawa. 2019. “ATR/FT-IR studies of zeolite formation during alkali-activation of metakaolin.” Solid State Sci. 94 (Jun): 114–119. https://doi.org/10.1016/j.solidstatesciences.2019.06.004.
Lee, N. K., and H. K. Lee. 2013. “Setting and mechanical properties of alkali-activated fly ash/slag concrete manufactured at room temperature.” Constr. Build. Mater. 47 (Jul): 1201–1209. https://doi.org/10.1016/j.conbuildmat.2013.05.107.
Li, N., C. Shi, and Z. Zhang. 2019. “Understanding the roles of activators towards setting and hardening control of alkali-activated slag cement.” Composites, Part B 171 (Apr): 34–45. https://doi.org/10.1016/j.compositesb.2019.04.024.
Liu, C., X. Yao, and W. Zhang. 2020. “Controlling the setting times of one-part alkali-activated slag by using honeycomb ceramics as carrier of sodium silicate activator.” Constr. Build. Mater. 235 (36): 117091. https://doi.org/10.1016/j.conbuildmat.2019.117091.
Liu, J.-C., Z. Chen, R. Cai, and H. Ye. 2022. “Quantitative effects of mixture parameters on alkali-activated binder-based ultra-high strength concrete at ambient and elevated temperatures.” J. Adv. Concr. Technol. 20 (1): 1–17. https://doi.org/10.3151/jact.20.1.
Mahmood, A. H., M. Babaee, S. J. Foster, and A. Castel. 2021. “Continuous monitoring of the early-age properties of activated GGBFS with alkaline solutions of different concentrations.” J. Mater. Civ. Eng. 33 (12): 04021374. https://doi.org/10.1061/(ASCE)MT.1943-5533.0003997.
Mahmoud, M., and M. Bassuoni. 2019. “Performance of concrete with alkali-activated materials and nanosilica in acidic environments.” J. Mater. Civ. Eng. 31 (3): 04019009. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002635.
Nath, P., and P. K. Sarker. 2014. “Effect of GGBFS on setting, workability and early strength properties of fly ash geopolymer concrete cured in ambient condition.” Constr. Build. Mater. 66 (5): 163–171. https://doi.org/10.1016/j.conbuildmat.2014.05.080.
Oderji, S. Y., B. Chen, C. Shakya, M. R. Ahmad, and S. F. A. Shah. 2019. “Influence of superplasticizers and retarders on the workability and strength of one-part alkali-activated fly ash/slag binders cured at room temperature.” Constr. Build. Mater. 229 (5): 116891. https://doi.org/10.1016/j.conbuildmat.2019.116891.
Palacios, M., P. F. Banfill, and F. Puertas. 2008. “Rheology and setting of alkali-activated slag pastes and mortars: Effect of organic admixture.” ACI Mater. J. 105 (2): 140.
Palacios, M., and F. Puertas. 2005. “Effect of superplasticizer and shrinkage-reducing admixtures on alkali-activated slag pastes and mortars.” Cem. Concr. Res. 35 (7): 1358–1367. https://doi.org/10.1016/j.cemconres.2004.10.014.
Thomas, R. J., H. Ye, A. Radlińska, and S. Peethamparan. 2016. “Alkali-activated slag concrete: A closer look at sustainable alternatives to Portland cement.” Concr. Int. 38 (1): 33–38.
Tong, S., Z. Yuqi, and W. Qiang. 2021. “Recent advances in chemical admixtures for improving the workability of alkali-activated slag-based material systems.” Constr. Build. Mater. 272 (2): 121647. https://doi.org/10.1016/j.conbuildmat.2020.121647.
Wang, S.-D., X.-C. Pu, K. L. Scrivener, and P. L. Pratt. 1995. “Alkali-activated slag cement and concrete: A review of properties and problems.” Adv. Cem. Res. 7 (27): 93–102. https://doi.org/10.1680/adcr.1995.7.27.93.
Wang, W.-C., H.-Y. Wang, and M.-H. Lo. 2015. “The fresh and engineering properties of alkali activated slag as a function of fly ash replacement and alkali concentration.” Constr. Build. Mater. 84 (Sep): 224–229. https://doi.org/10.1016/j.conbuildmat.2014.09.059.
Wu, X., W. Jiang, and D. M. Roy. 1990. “Early activation and properties of slag cement.” Cem. Concr. Res. 20 (6): 961–974. https://doi.org/10.1016/0008-8846(90)90060-B.
Ye, H., Z. Chen, and L. Huang. 2019. “Mechanism of sulfate attack on alkali-activated slag: The role of activator composition.” Cem. Concr. Res. 125 (12): 105868. https://doi.org/10.1016/j.cemconres.2019.105868.
Ye, H., and A. Radlińska. 2016. “Quantitative analysis of phase assemblage and chemical shrinkage of alkali-activated slag.” J. Adv. Concr. Technol. 14 (5): 245–260. https://doi.org/10.3151/jact.14.245.
Ye, H., G. Yang, and C. Fu. 2021. “Effect of dolomite filler on the sulfuric acid resistance of alkali-activated slag binders.” J. Mater. Civ. Eng. 33 (9): 04021219. https://doi.org/10.1061/(ASCE)MT.1943-5533.0003893.
Živica, V. 2007. “Effects of type and dosage of alkaline activator and temperature on the properties of alkali-activated slag mixtures.” Constr. Build. Mater. 21 (7): 1463–1469. https://doi.org/10.1016/j.conbuildmat.2006.07.002.
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Published In
Journal of Materials in Civil Engineering
Volume 35 • Issue 2 • February 2023
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© 2022 American Society of Civil Engineers.
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Received: Feb 2, 2022
Accepted: May 16, 2022
Published online: Nov 25, 2022
Published in print: Feb 1, 2023
Discussion open until: Apr 25, 2023
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