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

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement and Concrete Research Pub Date : 2025-01-27 DOI:10.1016/j.cemconres.2025.107807

Jiaxin Chen, Johann Plank

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引用次数: 0

Abstract

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 (R_h) 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 R_h 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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研究了不同 PCE（MPEG（甲基丙烯酸酯）、HPEG（甲基烯丙基醚）、EPEG（2-羟乙基聚（乙二醇）乙烯基醚）在 NaOH-Na2SiO3 活化的双组分矿渣粘结剂中的行为。根据 "浊点 "法，它们在两种活化剂溶液中的溶解度依次为 MPEG>>HPEG>>EPEG。GPC 色谱图证实，在 RT 状态下，所有 PCE 在活化剂溶液中都不会分解，与活化剂浓度和暴露时间（1 小时/1 天）无关。"小坍落度 "测试证实，HPEG 聚乙烯的分散效果最好，而 MPEG 聚乙烯的分散效果最差。当将 PCE 溶解在混合水中时，没有任何 PCE 可以分散 Na2SiO3 活性渣。吸附测试表明，在 NaOH 中不存在朗穆尔吸附行为，而在 Na2SiO3 浆料中几乎不存在吸附行为。DLS 测量显示，在 1-2 M NaOH 和 0.25 M Na2SiO3 中，PCE 分子的立体尺寸（Rh）减小，表明 PCE 聚合物发生了卷曲。在活化剂用量非常高的情况下（3 M NaOH 和 1 M Na2SiO3），由于多个聚合氯化乙烯分子聚集在一起，Rh 值显著增加。显然，PCE 在 AAS 中的有效性主要受其在 AAS 孔溶液中的溶解构象控制。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Cement and Concrete Research 工程技术-材料科学：综合

CiteScore

20.90

自引率

12.30%

发文量

318

审稿时长

53 days

期刊介绍： Cement and Concrete Research is dedicated to publishing top-notch research on the materials science and engineering of cement, cement composites, mortars, concrete, and related materials incorporating cement or other mineral binders. The journal prioritizes reporting significant findings in research on the properties and performance of cementitious materials. It also covers novel experimental techniques, the latest analytical and modeling methods, examination and diagnosis of actual cement and concrete structures, and the exploration of potential improvements in materials.