Wena de Nazaré do Rosário Martel, Josée Duchesne, Benoît Fournier
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Due to the lack of a tailored protocol for EPMA analysis of alkali-rich SCMs, this study established analytical conditions to minimize errors in quantifying pozzolanic GP. Mixed glass culets and GP particles embedded in 7-year-old ternary concrete made with GP and silica fume were analyzed using ten different current densities by varying beam size, current, and the sub-counting method. The results show that alkali migration is highly sensitive to material composition and irradiation conditions. Na losses exceeded 70% as Ca and Si overestimation reached approximately 13% at current densities above 0.354 nA/μm². Literature-reported densities often surpass this threshold. At those conditions, the implementation of a sub-counting method effectively reduces the Na loss to 3%. However, it introduced a tendency for Na overestimation at lower current densities. Among all conditions, a beam diameter of 6 µm and a current of 10 nA, was the most accurate, reducing losses to under 2% and closely matching the reference glass analysis.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100132"},"PeriodicalIF":0.0000,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Optimization of microprobe analysis of cementitious materials incorporating glass powder under electron beam to avoid alkali migration\",\"authors\":\"Wena de Nazaré do Rosário Martel, Josée Duchesne, Benoît Fournier\",\"doi\":\"10.1016/j.cement.2025.100132\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The growing use of alkali-rich glass powder (GP) as a supplementary cementitious material (SCM) in concrete has led to a rising number of studies focused on the microstructure of cementitious matrices incorporating GP. Electron probe microanalyzer (EPMA) is commonly used to characterize cementitious materials. However, alkali migration induced by electron irradiation - a well-known phenomenon in inorganic materials - remains underexplored in this context. This migration often leads to underestimation of Na and K and overestimation of Si and Ca, thus compromising the analysis of key elements in cementitious hydrates, such as C-S-H. Due to the lack of a tailored protocol for EPMA analysis of alkali-rich SCMs, this study established analytical conditions to minimize errors in quantifying pozzolanic GP. Mixed glass culets and GP particles embedded in 7-year-old ternary concrete made with GP and silica fume were analyzed using ten different current densities by varying beam size, current, and the sub-counting method. The results show that alkali migration is highly sensitive to material composition and irradiation conditions. Na losses exceeded 70% as Ca and Si overestimation reached approximately 13% at current densities above 0.354 nA/μm². Literature-reported densities often surpass this threshold. At those conditions, the implementation of a sub-counting method effectively reduces the Na loss to 3%. However, it introduced a tendency for Na overestimation at lower current densities. Among all conditions, a beam diameter of 6 µm and a current of 10 nA, was the most accurate, reducing losses to under 2% and closely matching the reference glass analysis.</div></div>\",\"PeriodicalId\":100225,\"journal\":{\"name\":\"CEMENT\",\"volume\":\"19 \",\"pages\":\"Article 100132\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2025-01-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"CEMENT\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2666549225000052\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"CEMENT","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2666549225000052","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
随着富碱玻璃粉(GP)作为一种补充胶凝材料(SCM)在混凝土中的应用越来越广泛,越来越多的研究关注于含GP的胶凝基质的微观结构。电子探针微量分析仪(EPMA)是一种常用的胶凝材料表征方法。然而,电子辐照引起的碱迁移——无机材料中一个众所周知的现象——在这方面仍未得到充分的研究。这种迁移往往导致Na和K的低估和Si和Ca的高估,从而影响了胶结水合物中关键元素(如C-S-H)的分析。由于缺乏适合富碱SCMs的EPMA分析方案,本研究建立了分析条件,以尽量减少定量火山灰GP的误差。混合玻璃碎片和GP颗粒嵌入在由GP和硅灰制成的7年的三元混凝土中,通过不同的光束大小,电流和子计数方法,使用十种不同的电流密度进行分析。结果表明,碱迁移对材料组成和辐照条件高度敏感。当电流密度大于0.354 Na /μ²时,Ca和Si的高估约为13%,Na损失超过70%。文献报道的密度经常超过这个阈值。在这些条件下,子计数方法的实施有效地将Na损耗降低到3%。然而,在较低的电流密度下,它引入了Na高估的趋势。在所有条件下,光束直径为6µm,电流为10 nA是最准确的,将损耗降低到2%以下,与参考玻璃分析结果非常吻合。
Optimization of microprobe analysis of cementitious materials incorporating glass powder under electron beam to avoid alkali migration
The growing use of alkali-rich glass powder (GP) as a supplementary cementitious material (SCM) in concrete has led to a rising number of studies focused on the microstructure of cementitious matrices incorporating GP. Electron probe microanalyzer (EPMA) is commonly used to characterize cementitious materials. However, alkali migration induced by electron irradiation - a well-known phenomenon in inorganic materials - remains underexplored in this context. This migration often leads to underestimation of Na and K and overestimation of Si and Ca, thus compromising the analysis of key elements in cementitious hydrates, such as C-S-H. Due to the lack of a tailored protocol for EPMA analysis of alkali-rich SCMs, this study established analytical conditions to minimize errors in quantifying pozzolanic GP. Mixed glass culets and GP particles embedded in 7-year-old ternary concrete made with GP and silica fume were analyzed using ten different current densities by varying beam size, current, and the sub-counting method. The results show that alkali migration is highly sensitive to material composition and irradiation conditions. Na losses exceeded 70% as Ca and Si overestimation reached approximately 13% at current densities above 0.354 nA/μm². Literature-reported densities often surpass this threshold. At those conditions, the implementation of a sub-counting method effectively reduces the Na loss to 3%. However, it introduced a tendency for Na overestimation at lower current densities. Among all conditions, a beam diameter of 6 µm and a current of 10 nA, was the most accurate, reducing losses to under 2% and closely matching the reference glass analysis.