{"title":"Which factors impact the effectiveness of PCEs in alkali-activated slag cements?","authors":"Jiaxin Chen, Johann Plank","doi":"10.1016/j.cemconres.2025.107807","DOIUrl":null,"url":null,"abstract":"Behavior of different PCEs (MPEG (methacrylate ester), HPEG (methallyl ether), EPEG (2-hydroxyethyl poly(ethylene glycol) vinyl ether) based PCE) in NaOH-/Na<sub>2</sub>SiO<sub>3</sub>-activated two-part slag binders was investigated. In both activator solutions their solubility follows the order MPEG<span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo is=\"true\">&gt;</mo></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"1.625ex\" role=\"img\" style=\"vertical-align: -0.235ex;\" viewbox=\"0 -598.2 778.5 699.5\" width=\"1.808ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-3E\"></use></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo is=\"true\">></mo></math></span></span><script type=\"math/mml\"><math><mo is=\"true\">></mo></math></script></span>HPEG<span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo is=\"true\">&gt;</mo></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"1.625ex\" role=\"img\" style=\"vertical-align: -0.235ex;\" viewbox=\"0 -598.2 778.5 699.5\" width=\"1.808ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-3E\"></use></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mo is=\"true\">></mo></math></span></span><script type=\"math/mml\"><math><mo is=\"true\">></mo></math></script></span>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 Na<sub>2</sub>SiO<sub>3</sub>-activated slag when PCE was dissolved in mixing water. Adsorption tests demonstrated non-<em>Langmuir</em> behavior in NaOH and almost no adsorption in Na<sub>2</sub>SiO<sub>3</sub> pastes. DLS measurements revealed that in 1–2 M NaOH and 0.25 M Na<sub>2</sub>SiO<sub>3</sub>, decreased steric size (R<sub>h</sub>) of PCE molecules was noted, indicating the coiling of PCE polymers. At very high activator dosages (3 M NaOH and 1 M Na<sub>2</sub>SiO<sub>3</sub>), remarkably increased R<sub>h</sub> 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.","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"120 1","pages":""},"PeriodicalIF":10.9000,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cement and Concrete Research","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1016/j.cemconres.2025.107807","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CONSTRUCTION & BUILDING TECHNOLOGY","Score":null,"Total":0}
Which factors impact the effectiveness of PCEs in alkali-activated slag cements?
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 MPEGHPEGEPEG 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.
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.