Using In Situ Chemical and Structure Mapping of Calcium Sulfoaluminate Cement to Control Hydration

利用硫铝酸钙水泥的原位化学和结构图来控制水化

• 批准号: 1635878
• 负责人: M. Tyler Ley
• 金额: $ 30万
• 依托单位: Oklahoma State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-15 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1635878&HistoricalAwards=false
• 关键词: Using; Situ; Chemical; Structure; Mapping

The most widely used construction material in the world is concrete, due to its durability, economy, and flexible form. Because concrete is so ubiquitous, it creates a sizable demand on resources. This means that even modest improvements in the durability and sustainability of concrete would lead to great societal and economic benefit. New cements are needed with improved performance that also require reduced resources to manufacture. Calcium sulfoaluminate cements are a good example of this. These cements have a 50 percent reduction in the carbon dioxide and energy required for their production when compared to traditional cement. These cements are capable of gaining comparable strengths in only three hours that traditional cements gain in a month. Furthermore, these materials show less cracking from drying. However, work is needed to understand and ultimately control the rate of hydration of calcium sulfoaluminate cements. This project aims to understand this group of cements by characterizing changes in the hydration reactions at nano and micro length scales using 3D in-situ structure and chemistry imaging techniques. The effects of additives on these hydration reactions modifying can also be examined and modified accordingly. These findings will be used to produce concretes with improved properties at lower costs and energy consumption. Also, the awareness level of STEM fields will be raised with underrepresented elementary students through the extension of an existing elementary engineering-oriented curriculum with the creation of new lesson plans for both online and in class delivery.The research will use 3D in-situ structure and chemistry imaging techniques at multiple length scales in combination with microstructural modeling to characterize, quantify, and understand the structure, chemistry, and properties of calcium sulfoaluminate cement reactions over the first 12 hours. These cements can gain service strengths in only a few hours and have the potential to reduce the carbon footprint of concrete by 50 percent. This work aims to understand changes in the structure and chemistry that occur in the dissolution of cement particles and the subsequent formation of early age hydration products by using 3D in-situ imaging techniques at the nanometer and micron scale. Bulk changes will also be evaluated by using mechanical testing, isothermal calorimetry, and X-ray diffraction. Next, these same experimental methods will be used to study how additives change the rate, structure, and chemistry of the hydrates. Finally, efforts will be made to understand the mechanisms by which these reactions occur and collaborate with the National Institute of Science and Technology to develop computational models that are able to guide the design and predict performance of early concrete properties. This work will improve economy, sustainability, and mechanical properties of concrete.

世界上使用最广泛的建筑材料是混凝土，因为它耐用、经济且形式灵活。 由于混凝土无处不在，因此对资源产生了巨大的需求。 这意味着，即使混凝土的耐久性和可持续性略有改善，也会带来巨大的社会和经济效益。 需要性能改进的新型水泥，同时也需要减少制造资源。 硫铝酸钙水泥就是一个很好的例子。 与传统水泥相比，这些水泥生产所需的二氧化碳和能源减少了 50%。 这些水泥能够在短短三个小时内获得与传统水泥一个月内获得的强度相当的强度。 此外，这些材料因干燥而产生的裂纹较少。 然而，需要开展工作来了解并最终控制硫铝酸钙水泥的水化速率。 该项目旨在通过使用 3D 原位结构和化学成像技术表征纳米和微米尺度上水合反应的变化来了解这组水泥。 添加剂对这些水合反应改性的影响也可以被检查和相应地修改。 这些发现将用于以更低的成本和能耗生产性能得到改善的混凝土。此外，通过扩展现有的以工程为导向的基础课程，并为在线和课堂教学创建新的课程计划，将提高代表性不足的小学生对 STEM 领域的认识水平。该研究将使用多个长度尺度的 3D 原位结构和化学成像技术，结合微观结构建模来表征、量化和理解钙的结构、化学和性质。 硫铝酸盐水泥在前 12 小时内发生反应。 这些水泥只需几个小时即可获得使用强度，并有可能将混凝土的碳足迹减少 50%。这项工作旨在通过使用纳米和微米尺度的 3D 原位成像技术，了解水泥颗粒溶解过程中发生的结构和化学变化以及随后形成的早期水化产物。 还将通过机械测试、等温量热法和 X 射线衍射来评估体积变化。 接下来，这些相同的实验方法将用于研究添加剂如何改变水合物的速率、结构和化学性质。 最后，我们将努力了解这些反应发生的机制，并与国家科学技术研究所合作开发能够指导设计和预测早期混凝土性能性能的计算模型。 这项工作将提高混凝土的经济性、可持续性和机械性能。

项目成果

Direct observation of void evolution during cement hydration

• DOI: 10.1016/j.matdes.2017.09.056
• 发表时间: 2017-12
• 期刊: Materials & Design
• 影响因子: 8.4
• 作者: M. Moradian;Qinang Hu;Mohammed Aboustait;M. T. Ley;J. Hanan;Xianghui Xiao;G. Scherer;Zhidong Zhang

Multi-scale observations of structure and chemical composition changes of portland cement systems during hydration

• DOI: 10.1016/j.conbuildmat.2019.04.013
• 发表时间: 2019-07
• 期刊: Construction and Building Materials
• 影响因子: 7.4
• 作者: M. Moradian;Qinang Hu;Mohammed Aboustait;M. T. Ley;J. Hanan;Xianghui Xiao;V. Rose;R. Winarski;G. Scherer

Direct in-situ observation of early age void evolution in sustainable cement paste containing fly ash or limestone

• DOI: 10.1016/j.compositesb.2019.107099
• 发表时间: 2019-10
• 期刊: Composites Part B: Engineering
• 作者: M. Moradian;Qinang Hu;Mohammed Aboustait;B. Robertson;M. T. Ley;J. Hanan;Xianghui Xiao