使用非侵入性技术进行水泥的分类和表征
Esteban Romero1, Dennis S Ferreira1, Fabiola M V Pereira2
1Departamento de Química Analítica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Instituto de Química Rosario (CONICET-UNR), Suipacha 531, 2000, Rosario, Argentina; Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, P.O. Box 676, São Carlos, São Paulo State, 13565-905, Brazil.
Talanta
|November 21, 2024
概括
这项研究开发了先进的分析方法,使用化学测量来准确量化水泥样本中的元素. 这些新技术提供了低检测极限和高精度,支持可持续建筑材料分析.
科学领域:
- 材料科学 材料科学 材料科学
- 分析化学 分析化学
- 环境科学 环境科学
背景情况:
- 水泥是全球生产的关键建筑材料,每年生产约40亿.
- 精确的水泥元素分析对于质量控制和了解其性能至关重要.
- 现有的分析方法可能资源密集,并产生大量的浪费.
研究的目的:
- 开发和验证用于水泥元素定量化的可靠分析方法.
- 应用多变量校准技术以提高精度和灵敏度.
- 建立环保的分析方法,减少废物产生.
主要方法:
- 准备了50个水泥样本 (11个初级,39个混合物) 和24个错误共变量.
- 使用激光诱导分解光谱 (LIBS) 和能量分散式X射线光 (ED-XRF) 的元素分析.
- 在酸矿化后的诱导合等离子体光学发射光谱学 (ICP OES).
- 多变量校准的应用:主要组件回归 (PCR),最大概率主要组件回归 (MLPCR),部分最小平方回归 (PLS) 和错误共差处罚回归 (ECPR).
主要成果:
- 开发具有高灵敏度 (0.3329 a.u.) 的强大的分析模型. (% w/w) -1) 的情况.
- 在关键元素的0.000.1% w/w之间实现了低检测极限 (LoD).
- 证明了显著的准确性 (67.8%140.3%),特别是对于Ca,Fe,Mg和Na.
结论:
- 新的化学测量技术使得水泥的精确和敏感的元素分析成为可能.
- 开发的方法为水泥表征提供了一个低浪费,环保的替代方案.
- 这项研究通过改进的分析方法来推进建筑材料行业的可持续实践.
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The fineness of cement directly influences the rate of hydration, as the hydration begins at the surface of the cement particles. In addition to hydration, the fineness of cement is vital for various properties of concrete including workability, gypsum requirement, and long-term behavior. The fineness of cement is represented in terms of the specific surface of cement which is typically measured in square meters per kilogram, with several methods available for this determination.
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01:22Types of Cement II
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01:21Types of Cement I
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Portland cement comes in several types, each with distinct properties and applications based on their chemical composition and hydration characteristics:
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01:17Soundness of Cement
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The soundness of cement refers to the ability of cement paste to retain its volume after setting. Unsound cement can lead to expansion and structural damage due to the presence of free lime, magnesia, and calcium sulfate. Free lime hydrates very slowly, expanding and causing unsoundness, which is difficult to detect because it intercrystallizes with other compounds. Magnesia also reacts with water, forming crystals that can disrupt the cement's structure. Calcium sulfate can create...
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01:20Strength of Cement
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Strength tests for cement are not performed directly on neat cement paste due to difficulty in obtaining consistent, reliable specimens. Instead, cement is typically tested in the form of cement-sand mortar.
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01:18Porosity in Cement Paste
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The porosity of concrete is a measure of the void spaces within its structure. These spaces impact its strength and durability significantly. When water and cement interact, a chemical reaction called hydration creates a semi-solid paste. This paste includes combined water, making up approximately 23% of the cement's dry mass, and gel water, which fills minuscule voids known as gel pores, accounting for about 28% of the cement gel volume.
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