Effects of the pre-absorption of superabsorbent polymers and the water-cement ratio of paste on the adsorption-desorption of superabsorbent polymers: an NMR study

Conference paper (2021)

Authors

Jingbin Yang Tongji University, China
Zhenping Sun Tongji University, China
Ji Yanliang Tongji University, China
Biyun Li Tongji University, China
Min Pang Tongji University, China
Copyright: © 2021 the authors
Superabsorbent polymers Mixing method Water-cement ratio 1H low-field NMR
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Published Date

29-04-2021

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Abstract

As an internal curing material, superabsorbent polymers (SAPs) can effectively reduce the risk of volume shrinkage of cement-based materials. By preparing the cement paste mixed with SAPs, the amount of pre-absorbed water and the water-cement ratio of paste on the water absorption-release behavior in the fresh cement paste were studied by using 1H low-field NMR. The results showed that when the water-cement ratio was 0.30, the SAPs without pre-absorption could absorb the mixing water from the fresh paste and stored the mixing water in the SAPs relatively stable, while the pre-absorbed SAPs released the absorbed water into the paste rapidly, and the more pre-absorbed water, the faster the water released after mixing. When the watercement ratio was increased to 0.40, the mixing water absorbed by SAPs without pre-absorption was more than that absorbed by SAPs when the water-cement ratio was 0.30, but in the system with super high water-cement ratio of 0.50, the SAPs cannot absorb mixing water from the paste after mixing.