{"title":"论磷酸盐系超塑化剂在单组分碱活性矿渣中的作用机理","authors":"","doi":"10.1016/j.cemconres.2024.107659","DOIUrl":null,"url":null,"abstract":"<div><p>The mechanisms responsible for the compromised or lost dispersing capability of polycarboxylate ether (PCE) superplasticizers in two-part alkali-activated slag (AAS) have been extensively studied, but limited scientific understanding is available on how PCEs function or lose their dispersing efficiency in one-part AAS systems, particularly those prepared using greener carbonate -based solid activators. This study investigates the dispersing and adsorption behaviors of phosphate-based PCE in one-part AAS activated by K<sub>2</sub>CO<sub>3</sub> or a combination of K<sub>2</sub>CO<sub>3</sub> and CaO. Our findings indicate that in K<sub>2</sub>CO<sub>3</sub>-activated slag systems, the loss of phosphate-based PCE efficiency primarily results from the conformational contraction of PCE molecules, which deteriorates steric repulsion in the alkaline activating solution, rather than the insolubility of PCEs in alkaline solution or competitive adsorption between PCEs and carbonate anions on dissolving slag grains. In K<sub>2</sub>CO<sub>3</sub>-CaO-activated slag systems, when PCE dosage is below 5 mg/g, the consumption of PCE by early precipitates (e.g., C-A-S-H, gaylussite, calcite) contributes substantially to its lost efficiency; however, once the PCE dosage surpasses this threshold, the dominant factor influencing PCE efficiency shifts to the conformational change of PCE.</p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":null,"pages":null},"PeriodicalIF":10.9000,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On the action mechanism of phosphate-based superplasticizers in one-part alkali-activated slag\",\"authors\":\"\",\"doi\":\"10.1016/j.cemconres.2024.107659\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The mechanisms responsible for the compromised or lost dispersing capability of polycarboxylate ether (PCE) superplasticizers in two-part alkali-activated slag (AAS) have been extensively studied, but limited scientific understanding is available on how PCEs function or lose their dispersing efficiency in one-part AAS systems, particularly those prepared using greener carbonate -based solid activators. This study investigates the dispersing and adsorption behaviors of phosphate-based PCE in one-part AAS activated by K<sub>2</sub>CO<sub>3</sub> or a combination of K<sub>2</sub>CO<sub>3</sub> and CaO. Our findings indicate that in K<sub>2</sub>CO<sub>3</sub>-activated slag systems, the loss of phosphate-based PCE efficiency primarily results from the conformational contraction of PCE molecules, which deteriorates steric repulsion in the alkaline activating solution, rather than the insolubility of PCEs in alkaline solution or competitive adsorption between PCEs and carbonate anions on dissolving slag grains. In K<sub>2</sub>CO<sub>3</sub>-CaO-activated slag systems, when PCE dosage is below 5 mg/g, the consumption of PCE by early precipitates (e.g., C-A-S-H, gaylussite, calcite) contributes substantially to its lost efficiency; however, once the PCE dosage surpasses this threshold, the dominant factor influencing PCE efficiency shifts to the conformational change of PCE.</p></div>\",\"PeriodicalId\":266,\"journal\":{\"name\":\"Cement and Concrete Research\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":10.9000,\"publicationDate\":\"2024-09-06\",\"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://www.sciencedirect.com/science/article/pii/S0008884624002400\",\"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}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cement and Concrete Research","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0008884624002400","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}
On the action mechanism of phosphate-based superplasticizers in one-part alkali-activated slag
The mechanisms responsible for the compromised or lost dispersing capability of polycarboxylate ether (PCE) superplasticizers in two-part alkali-activated slag (AAS) have been extensively studied, but limited scientific understanding is available on how PCEs function or lose their dispersing efficiency in one-part AAS systems, particularly those prepared using greener carbonate -based solid activators. This study investigates the dispersing and adsorption behaviors of phosphate-based PCE in one-part AAS activated by K2CO3 or a combination of K2CO3 and CaO. Our findings indicate that in K2CO3-activated slag systems, the loss of phosphate-based PCE efficiency primarily results from the conformational contraction of PCE molecules, which deteriorates steric repulsion in the alkaline activating solution, rather than the insolubility of PCEs in alkaline solution or competitive adsorption between PCEs and carbonate anions on dissolving slag grains. In K2CO3-CaO-activated slag systems, when PCE dosage is below 5 mg/g, the consumption of PCE by early precipitates (e.g., C-A-S-H, gaylussite, calcite) contributes substantially to its lost efficiency; however, once the PCE dosage surpasses this threshold, the dominant factor influencing PCE efficiency shifts to the conformational change of PCE.
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.