Nanoscale Characterization of Expansion Due to Delayed Ettringite Formation

钙矾石形成延迟引起的膨胀的纳米级表征

• 批准号: 1030209
• 负责人: Benjamin Mohr
• 金额: $ 29.99万
• 依托单位: Tennessee Technological University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1030209&HistoricalAwards=false
• 关键词: Nanoscale; Characterization; Expansion; Due; Delayed

The primary objective of this research is to investigate the nano- and micro-scale mechanisms of late age ettringite formation and how these mechanisms relate to macro-scale expansion in concrete materials, enabling possible mitigation strategies for damage due to the late age formation of ettringite. This research will examine the chemical and physical structure of the reactants and products, as well as the pore structure evolution, involved in the process of late age ettringite formation and subsequent expansion and cracking. A more thorough understanding of the crystalline pressures induced on the microstructure will result by refining existing models with analytical techniques such as nanoindentation and residual stress analyses.Concrete is the most widely used engineering material in the world, yet is still poorly understand in many regards. The prevention of delayed ettringite formation, which is known to cause concrete cracking, would significantly improve the infrastructure life span of the United States and abroad. Educational activities will include traveling to local middle and high schools to provide hands-on experiments that give the students a real-life view of how engineering is an important part of the modern world. Local primary school groups will be invited to campus to participate in hands-on learning experiences at Tennessee Tech?s STEM Center. In addition to the educational activities, a residual stress analysis workshop is proposed at the end of the project to disseminate the strong background in this field at Tennessee Tech to other cement and concrete researchers; thus, expanding beyond traditional K-12 outreach.

本研究的主要目的是研究晚期钙矾石形成的纳米和微米尺度机制，以及这些机制如何与混凝土材料的宏观尺度膨胀相关，从而为后期钙矾石形成造成的损害提供可能的缓解策略。本研究将研究反应物和产物的化学和物理结构，以及孔结构的演变，参与了后期钙矾石的形成和随后的膨胀和开裂的过程。 通过纳米压痕和残余应力分析等分析技术对现有模型进行改进，可以更深入地了解微结构上的结晶压力。混凝土是世界上应用最广泛的工程材料，但在许多方面仍然知之甚少。延迟钙矾石的形成，这是已知的导致混凝土开裂的预防，将显着提高美国和国外的基础设施寿命。 教育活动将包括前往当地的初中和高中，提供动手实验，让学生对工程如何成为现代世界的重要组成部分有一个真实的看法。当地小学团体将被邀请到校园参加田纳西理工学院的实践学习体验？的STEM中心。除了教育活动外，还建议在项目结束时举办一个残余应力分析研讨会，向其他水泥和混凝土研究人员传播田纳西理工学院在该领域的强大背景;从而超越传统的K-12推广。