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，应力诱导的溶解是各种矿物质的主要时间依赖性变形机制。基于最近的建模工作，有理由相信压力诱导的溶解也是胶结材料中的重要变形机制。因此，化学，微结构发展的演变与压力和应变状态之间存在预期的耦合。该项目的主要目的是开发一个基本的热力学模型框架，该模型框架将不断发展的系统化学和水泥材料的力学联系起来，并通过一种计算方法来实施该模型，该方法可以预测微观结构和粘弹性/粘质性能的完全耦合演化。在与基本建模的协同作用下，将对应力标本的时间步变的微型层析成像进行新颖的实验，以测试应力诱导胶结材料溶解的假设。该项目的结果将导致理解构成性质的演变和潜在变形机制的重要进展。这最终将有助于以更大的强度，韧性，耐用性和可持续性来实现混凝土设计。混凝土是世界第二大商品，遭受了许多结构性和耐用性问题，导致了实质性的经济和环境成本。水泥材料（例如混凝土）的缺点可能部分归因于与缺乏可用的建模工具相关的设计限制，以有效地预测材料结构和特性的演变。该项目的结果将通过提供先进的建模，实验性和计算工具来帮助改善水泥材料的经济性，耐用性和可持续性来提供社会利益。此外，其他研究人员最终将能够自由实施该项目中开发的工具，以解决有关混凝土的许多重要问题，例如由于冻融循环和化学攻击而导致的降解。一种涉及化学和机械过程（例如变形）之间基本理论和耦合的建模方法，具有最终改变我们对水泥材料（例如混凝土）行为的理解的能力。