Abstract
At early ages, plastic shrinkage can arise when a cement paste is subjected to harsh drying conditions during hardening. Furthermore, when using a low water-to-binder ratio, the cementitious material may show autogenous shrinkage during setting. Super Absorbent Polymers (SAPs) are a promising admixture to mitigate shrinkage in cement pastes. By introducing internal curing by means of the stored mixing water in the SAPs, the plastic shrinkage can be partially mitigated, next to the mitigation of autogenous shrinkage during setting of the cement paste. The kinetics of water release by the SAPs towards the cementitious matrix are an important factor. To effectively and non-destructively monitor the effects induced by the SAPs during the plastic and hardening period as a function of time, Nuclear Magnetic Resonance (NMR) was applied. Using NMR, a clear distinction could be made in terms of the free water signal and the entrained water signal for SAP particles. The SAPs are able to protect the cement paste internally from the harsh ambient drying conditions by sustaining the internal relative humidity. The plastic settlement was reduced and there was less plastic shrinkage measured. By mitigating shrinkage, shrinkage cracking can be partially prevented. However, upon acting mechanical stresses, the cementitious material may crack nevertheless. SAPs are also interesting to first seal a crack due to their swelling capacity and to heal cracks afterwards by promoting autogenous healing. This healing was also monitored by NMR as a function of healing cycles and the amount of healing products formed were estimated based on the water signals obtained by NMR. Part of the water going into the crack was used to trigger further hydration of unhydrated cement particles. Healing in wet/dry cycles was stimulated by means of SAPs and healing at high relative humidity conditions only occurred in samples containing SAPs.
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References
Dudziak, L., Mechtcherine, V.: Enhancing early-age resistance to cracking in high-strength cement based materials by means of internal curing using super absorbent polymers. In: Brameshuber, W. (ed.) International RILEM Conference on Material Science, RILEM Publications S.A.R.L., pp. 129–139 (2010)
Friedemann, K., Stallmach, F., Kärger, J.: NMR diffusion and relaxation studies during cement hydration—a non-destructive approach for clarification of the mechanism of internal post curing of cementitious materials. Cem. Concr. Res. 36(5), 817–826 (2006)
Huang, H., Ye, G., Pel, L.: New insights into autogenous self-healing in cement paste based on nuclear magnetic resonance (NMR) tests. Mat. Struc. 47, 1–15 (2016). https://doi.org/10.1617/s11527-015-0664-9
Jensen, O.M., Hansen, P.F.: Water-entrained cement-based materials I. principles and theoretical background. Cem. Concr. Res. 31(4), 647–654 (2001)
Lee, H.X.D., Wong, H.S., Buenfeld, N.R.: Potential of superabsorbent polymer for self-sealing cracks in concrete. Adv. Appl. Ceram. 109(5), 296–302 (2010)
Mechtcherine, V., Reinhardt, H.W. (eds.): Application of Super Absorbent Polymers (SAP) in Concrete Construction. Springer, The Netherland (2012). https://doi.org/10.1007/978-94-007-2733-5
Mechtcherine, V., Schröfl, C., Wyrzykowski, M., Gorges, M., Cusson, D., Margeson, J., et al.: Effect of superabsorbent polymers (SAP) on the freeze-thaw resistance of concrete: results of a RILEM interlaboratory test. Mat. Struc. 50(14), 1–19 (2017). https://doi.org/10.1617/s11527-016-0868-7
Mechtcherine, V., Snoeck, D., Schröfl, C., De Belie, N., Klemm, A.J., Ichimiya, K., et al.: Testing superabsorbent polymer (SAP) sorption properties prior to implementation in concrete: results of a RILEM Round-Robin test. Mat. Struc. (2018). https://doi.org/10.1617/s11527-018-1149-4
Nestle, N., Kühn, A., Friedemann, K., Horch, C., Stallmach, F., Herth, G.: Water balance and pore structure development in cementitious materials in internal curing with modified superabsorbent polymers studied by NMR. Microporous and Mesoporous Mater. 125(1–2), 51–57 (2009)
Schröfl, C., Snoeck, D., Mechtcherine, V.: A review of characterisation methods for superabsorbent polymer (SAP) samples to be used in cement-based construction materials - Report of the RILEM TC 260-RSC. Mat. Struct. 50(197), 1–19 (2017). https://doi.org/10.1917/s11527-017-1060-4
Snoeck, D.: Self-healing and microstructure of cementitious materials with microfibres and superabsorbent polymers. Doctor in Civil Engineering: Construction Design, Ghent University, Ghent (2015)
Snoeck, D.: Superabsorbent polymers to seal and heal cracks in cementitious materials. RILEM Tech. Lett. 3, 32–38 (2018)
Snoeck, D., Jensen, O.M., De Belie, N.: The influence of superabsorbent polymers on the autogenous shrinkage properties of cement pastes with supplementary cementitious materials. Cem. Concr. Res. 74, 59–67 (2015)
Snoeck, D., Pel, L., De Belie, N.: The water kinetics of superabsorbent polymers during cement hydration and internal curing visualized and studied by NMR. Sci. Rep. 7(9514), 1–14 (2017). https://doi.org/10.1038/s41598-017-10306-0
Snoeck, D., Pel, L., De Belie, N.: Superabsorbent polymers to mitigate plastic drying shrinkage in a cement paste as studied by NMR. Cem. Concr. Compos. 93, 54–62 (2018a)
Snoeck, D., Schröfl, C., Mechtcherine, V.: Recommendation of RILEM TC 260-RSC: testing sorption by superabsorbent polymers (SAP) prior to implementation in cement-based material. Mat. Struct. 51(116), 1–7 (2018b)
Snoeck, D., Van Tittelboom, K., Steuperaert, S., Dubruel, P., De Belie, N.: Self-healing cementitious materials by the combination of microfibres and superabsorbent polymers. J. Intell. Mat. Syst. Struct. 25(1), 13–24 (2014). https://doi.org/10.1177/1045389X12438623
Acknowledgements
As a Postdoctoral Research Fellow of the Research Foundation-Flanders (FWO-Vlaanderen), D. Snoeck would like to thank the foundation for the financial support for this fellowship (12J3617Â N) and for the research stay as Guest Researcher at the Technical University of Eindhoven (TU/e) (V420617Â N). The authors want to thank Dr. A. Assmann and Dr. G. Herth from BASF for providing SAP A.
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Snoeck, D., Pel, L., De Belie, N. (2020). Kinetics of SAPs During Hardening, Drying and Healing in Cementitious Materials Studied by NMR. In: Boshoff, W., Combrinck, R., Mechtcherine, V., Wyrzykowski, M. (eds) 3rd International Conference on the Application of Superabsorbent Polymers (SAP) and Other New Admixtures Towards Smart Concrete. SAP 2019. RILEM Bookseries, vol 24. Springer, Cham. https://doi.org/10.1007/978-3-030-33342-3_15
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DOI: https://doi.org/10.1007/978-3-030-33342-3_15
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