Which factors impact the effectiveness of PCEs in alkali-activated slag cements?

被引：2
作者：
Chen, Jiaxin [1 ]
Plank, Johann [1 ]
机构：
[1] Tech Univ Munich, Inst Adv PCE Studies, Construct Chem, Lichtenbergstr 4, D-85747 Garching, Germany
来源：
CEMENT AND CONCRETE RESEARCH | 2025年 / 190卷
关键词：
Ground granulated blast furnace slag (GGBFS); Alkali-activated slag (AAS); Polycarboxylate (PCE); Stability; Solubility; POLYCARBOXYLATE SUPERPLASTICIZERS; POLY(ETHYLENE GLYCOL); ADMIXTURES; SHRINKAGE; HYDRATION; PASTES; ADSORPTION; RHEOLOGY; BEHAVIOR;
D O I：
10.1016/j.cemconres.2025.107807
中图分类号：
TU [建筑科学];
学科分类号：
0813 ;
摘要：
Behavior of different PCEs (MPEG (methacrylate ester), HPEG (methallyl ether), EPEG (2-hydroxyethyl poly (ethylene glycol) vinyl ether) based PCE) in NaOH-/Na2SiO3-activated two-part slag binders was investigated. In both activator solutions their solubility follows the order MPEG>HPEG>EPEG according to "cloud point" method. GPC chromatograms confirmed that at RT all PCEs don't decompose in activator solutions, independent of activator concentration and exposure time (1h/1d). "Mini-slump" tests confirmed the highest dispersing effectiveness of HPEG PCE, and the least for MPEG PCE. No PCE could disperse Na2SiO3-activated slag when PCE was dissolved in mixing water. Adsorption tests demonstrated non-Langmuir behavior in NaOH and almost no adsorption in Na2SiO3 pastes. DLS measurements revealed that in 1-2 M NaOH and 0.25 M Na2SiO3, decreased steric size (Rh) of PCE molecules was noted, indicating the coiling of PCE polymers. At very high activator dosages (3 M NaOH and 1 M Na2SiO3), remarkably increased Rh values due to the agglomeration of several PCE molecules was observed. Apparently, PCE effectiveness in AAS is strongly controlled by its solved conformation in AAS pore solution.
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页数：15
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