Abstract
Polyacrylamide (PAM) superabsorbent polymer microspheres were synthesized for use as internal curing agents in low water-to-cement ratio mixtures. An increase in PAM swelling capacity in pore solutions was achieved by reducing the crosslinking density during synthesis: 5.1 g/g swelling was observed for 2 wt.% crosslinker and 20.6 g/g for 0.5 wt.% crosslinker. Capillary micromechanical experiments showed that a reduction in crosslinking density decreased the PAM elastic modulus from 1100 ± 310 kPa to 110 ± 15 kPa. Yet all PAM maintained mechanical integrity when mixed with cement and cured under a compressive load. SEM analysis showed hydrated product formation within cement voids left behind by dehydrated PAM. PAM with reduced crosslinking densities resulted in a 26 ± 7.3% increase in hydrated product formation within these voids. Cement paste density and compressive strength was not compromised by the addition of PAM.
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Davis, C.R., Bose, B., Alcaraz, A.M., Martinez, C.J., Erk, K.A. (2020). Altering the Crosslinking Density of Polyacrylamide Hydrogels to Increase Swelling Capacity and Promote Calcium Hydroxide Growth in Cement Voids. 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_3
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DOI: https://doi.org/10.1007/978-3-030-33342-3_3
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