Collaborative Research: Coupling System Chemistry and Time-Dependent Deformation of Cementitious Materials through Evolving Thermodynamic States

合作研究：通过演化热力学状态耦合系统化学和胶凝材料随时间的变形

• 批准号: 1300500
• 负责人: Kumbakonam Rajagopal
• 金额: $ 3万
• 依托单位: Texas A&M Engineering Experiment Station
• 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: 2013-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1300500&HistoricalAwards=false
• 关键词: Collaborative; Research; Coupling; System; Chemistry

Recent research indicates that stress induced dissolution is a primary time-dependent deformation mechanism of various minerals. Based on recent modeling efforts, there is reason to believe that stress induced dissolution is also a significant deformation mechanism in cementitious materials. Thus, there is an expected coupling between the evolution of chemistry, microstructure development, and stress and strain states within cementitious materials. A primary objective of this project is to develop a fundamental thermodynamic model framework that links evolving system chemistry and mechanics of cementitious materials, and to implement the model through a computational method that predicts the fully coupled evolution of microstructure and viscoelastic/viscoplastic properties of the materials. In synergy with the fundamental modeling, novel experiments using time-stepping micro-computed tomography of stressed specimens will be performed to test the hypothesis that stress induces dissolution in cementitious materials. The results of this project will lead to important advances in understanding the evolution of constitutive properties and the underlying deformation mechanisms; this will ultimately help enable design of concrete with greater strength, toughness, durability, and sustainability. Concrete, the second most used commodity in the world, suffers from many structural and durability issues that result in substantial economic and environmental costs. The drawbacks of cementitious materials such as concrete may be attributed in part to design limitations associated with the lack of available modeling tools for effectively predicting the evolution of the material structure and properties. The results of this project will provide societal benefit by providing advanced modeling, experimental, and computational tools to help improve the economy, durability and sustainability of cementitious materials. Furthermore, other researchers will ultimately be able to freely implement the tools developed in this project to address a host of important issues with respect to concrete, such as degradation due to freeze-thaw cycling and chemical attack. A modeling approach that involves fundamental theory and coupling between chemistry and mechanical processes (such as deformation) has the capability to ultimately transform our understanding of the behavior of cementitious materials such as concrete.

最近的研究表明，应力引起的溶解是各种矿物的主要与时间相关的变形机制。根据最近的建模工作，有理由相信应力引起的溶解也是胶凝材料的重要变形机制。因此，水泥材料内的化学演化、微观结构发展以及应力和应变状态之间存在预期的耦合。该项目的主要目标是开发一个基本的热力学模型框架，将不断发展的系统化学和水泥材料力学联系起来，并通过预测材料的微观结构和粘弹性/粘塑性特性的完全耦合演化的计算方法来实现该模型。与基本模型协同作用，将使用应力样本的时间步进微计算机断层扫描进行新颖的实验，以检验应力引起水泥材料溶解的假设。该项目的结果将在理解本构特性的演变和潜在的变形机制方面取得重要进展；这最终将有助于设计出具有更高强度、韧性、耐久性和可持续性的混凝土。混凝土是世界上使用量第二大的商品，存在许多结构和耐久性问题，导致巨大的经济和环境成本。混凝土等水泥材料的缺点可能部分归因于与缺乏有效预测材料结构和性能演变的可用建模工具相关的设计限制。该项目的成果将通过提供先进的建模、实验和计算工具来帮助提高水泥材料的经济性、耐久性和可持续性，从而带来社会效益。此外，其他研究人员最终将能够自由地实施该项目中开发的工具，以解决与混凝土有关的一系列重要问题，例如冻融循环和化学侵蚀引起的降解。涉及基础理论以及化学和机械过程（例如变形）之间耦合的建模方法有能力最终改变我们对混凝土等水泥材料行为的理解。