Characterizing Paste Microstructure during Setting with Combined Raman Spectroscopy and Confocal Microscopy

结合拉曼光谱和共焦显微镜表征凝固过程中的膏体微观结构

• 批准号: 1265983
• 负责人: Zhihui Sun
• 金额: $ 20万
• 依托单位: University of Louisville Research Foundation Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-15 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1265983&HistoricalAwards=false
• 关键词: Characterizing; Paste; Microstructure; during; Setting

The research goal of this project is to enhance our knowledge of cement setting on microstructural level by exploring the dispersion, agglomeration and percolation mechanism of cement particles with advanced physical and chemical imaging methods. To achieve this goal, Raman spectroscopy combined with confocal microscopy will be conducted in real-time on fresh cement pastes. Raman spectroscopy will firstly be applied to both dry cement powder and fresh paste to trace changes in the chemical compositions during early hydration. A Raman library of clinker phases and hydration products will be developed. Then, the Raman spectroscopy will be combined with confocal microscopy to conduct real-time observation on the physical dispersion of particles together with chemical dispersion (chemical mapping) in order to investigate the influence of chemical ingredients and surface chemistry of the particle flocculation. The physical and chemical microstructural parameters will be correlated to the setting time and hydration heat signature using a moving window modeling approach. The setting and hardening process is considered to be the most critical time period for a concrete structure, during which chemical, physical and mechanical properties of the concrete undergo rapid changes. Remixing, recasting, or replacing cannot be implemented after setting. Thus having solid knowledge about the setting behavior of concrete is essential to guarantee the quality and performance of the material. Concrete setting is governed by paste setting that is caused by the distribution, movement, and connection of cement particles. An in-situ observation of the particle flocculation, agglomeration and percolation processes during the initial hydration period will provide fundamental understanding of paste setting behavior, so that the concrete construction process can be controlled. By combining Raman spectroscopy and confocal microscopy, this proposed work will build up a database on early-age hydration that will be useful to the concrete industry, specifically chemical admixture companies. This database will also be useful for hydration/microstructural development models. Educational plan focuses on training undergraduate and graduate students with better critical thinking and research skills. Outreach activities, such as INSPIRE and E-Expo, are also planned for diverse groups of K-12 students, including minority and female students.

该项目的研究目标是通过探索采用先进的物理和化学成像方法的水泥颗粒的分散，聚集和渗透机制来增强我们对微观结构水平上的水泥设置的了解。为了实现这一目标，将在新鲜水泥糊中实时进行拉曼光谱与共聚焦显微镜结合。拉曼光谱法首先将应用于干燥的水泥粉和新鲜糊剂，以追踪早期水合过程中化学成分的变化。将开发一个熟料阶段和水合产品的拉曼库。然后，拉曼光谱将与共聚焦显微镜结合使用，以对颗粒的物理分散以及化学分散（化学映射）进行实时观察，以研究化学成分和颗粒絮凝的表面化学的影响。物理和化学微观结构参数将使用移动窗口建模方法与设定时间和水合热签名相关。设置和硬化过程被认为是混凝土结构最关键的时间段，在此期间，混凝土的化学，物理和机械性能经历了快速变化。设置后无法实现，重新混合，翻新或替换。因此，对混凝土的设定行为有牢固的知识对于保证材料的质量和性能至关重要。混凝土设置由由水泥颗粒的分布，运动和连接引起的糊状设置控制。对颗粒絮凝，聚集和渗滤过程的原位观察将提供对糊剂设定行为的基本理解，以便可以控制混凝土的施工过程。 通过将拉曼光谱和共聚焦显微镜相结合，这项拟议的工作将建立一个有关早期水合的数据库，该数据库将对混凝土行业，特别是化学混合公司有用。该数据库也可用于水合/微结构开发模型。教育计划的重点是培训本科生和研究生，具有更好的批判性思维和研究技能。还计划针对包括少数民族和女学生在内的不同K-12学生组成的外展活动，例如Inspire和E-Expo。