| Autor: |
Junyi Zhang, Huan Ye, Xiaojian Gao, Weidong Wu |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
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| Zdroj: |
Journal of Materials Research and Technology, Vol 17, Iss , Pp 1740-1751 (2022) |
| Druh dokumentu: |
article |
| ISSN: |
2238-7854 |
| DOI: |
10.1016/j.jmrt.2022.01.145 |
| Popis: |
The adsorption behavior of polycarboxylate ether (PCE) superplasticizer in fresh cement-based materials has been well investigated, but its desorption behavior was little reported. To facilitate deeper understanding the dispersion effect of PCE on binder particles, this research focused on both adsorption and desorption of PCE polymers in unitary or binary fresh paste blended with mineral admixtures as supplementary cementitious materials (SCMs), and thus aimed to give insights into interactions of PCE and SCMs. Five kinds of SCMs including fly ash (FA), ground granulated blast-furnace slag (GGBS) and limestone (LS) were adopted in experiment. The adsorption and desorption amounts of PCE were evaluated by measuring the concentration of PCE polymers remaining in liquid phase before and after dilution treatment. Results showed that only little desorption of adsorbed PCE occurred in unitary cement paste, but the desorption behavior of PCE was pronounced in unitary pastes for SCMs with similar particles size distribution to cement. For binary pastes, the incorporation of FA or GGBS in cement suspension led to more adsorption amount with a higher desorption ratio freshly, but after prolonged mixing duration the desorption was substantially reduced to nearly zero. The addition of LS powder in cement paste can inhibit the desorption behavior of PCE since the initial stage. The dissolution and release of calcium or sulfate from SCMs into solution could exert a remarkable promoting or inhibiting effect on PCE adsorption. The mechanisms could be explained from the perspective of colloidal particles surface chemistry. Consequently, the adsorption and desorption of PCE molecules in fresh blended cementitious materials largely depended on intrinsic physico-chemical properties of SCMs, including mineral components, hydration activity, particles size, morphology and zeta potential. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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