Concrete Micromechanics Validated with In-Situ Stress and Strain Measurements

通过现场应力和应变测量验证混凝土微观力学

• 批准号: 2125023
• 负责人: Ryan Hurley
• 金额: $ 35.16万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2125023&HistoricalAwards=false
• 关键词: Concrete; Micromechanics; Validated; Situ; Stress

This research will examine the mechanical response of concrete at micrometer to centimeter length scales to validate theories and computational models used to predict its behavior and failure. Concrete is the world’s most-common building material and extensive research efforts are on-going to improve its resiliency and environmental friendliness. Concrete is composed of particles and inclusions with varying properties and dimensions ranging from nanometers to centimeters that interact during mechanical loading. The results of these interactions are captured by theories and computational models in the field of micromechanics. While micromechanics-based theories accurately predict many mechanical properties of concrete, the assumptions underlying these theories have not been validated at small length scales. Furthermore, determining the resolution needed for accurate computational modeling of concrete is still challenging. This research project will employ new, advanced x-ray measurements to assess the response of concrete from micrometers to centimeters, to test the hypotheses underlying micromechanics theories, and to provide the research community with high-fidelity data for validating models. The results of this research are expected to improve predictions of concrete’s mechanical response and promote understanding of its properties. The research results will also be used to teach advanced concepts in a graduate engineering course and to provide research opportunities to under-represented high school students interested in STEM careers.This research consists of making in-situ x-ray tomography and diffraction measurements of stress and strain at micron to centimeter length scales during mechanical loading of concrete specimens at laboratory and synchrotron facilities. These measurements will be used to validate and extend micromechanics theories, such as Eshelby’s inclusion and Mori-Tanaka’s theories, and their underlying assumptions across length scales. For instance, the measurements will be used to examine whether average inclusion stresses used as intermediate variables in deriving homogenized material properties are accurate and to what degree individual inclusion stresses deviate from the average. The measurements will also be used to examine the accuracy of mesoscale modeling with varying levels of microstructural refinement, addressing open problems related to the length scales that must be captured in such models. The outcomes of the project will be a fundamental understanding of stress and strain variability across length scales in concrete, guidance for mesoscale modeling, and high-fidelity datasets for calibration and validation of theories and models used throughout the research community.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

这项研究将检查千分尺对厘米长度尺度的混凝土的机械响应，以验证用于预测其行为和失败的理论和计算模型。混凝土是世界上最常见的建筑材料，并且正在进行广泛的研究工作，以提高其弹性和环境友善。混凝土由颗粒和夹杂物组成，其特性不同，尺寸从纳米到厘米，在机械载荷期间相互作用。这些相互作用的结果是由微力学领域中的理论和计算模型捕获的。尽管基于微力学的理论可以准确预测混凝土的许多机械性能，但这些理论的基础假设尚未在较小的长度尺度上进行验证。此外，确定混凝土准确计算建模所需的分辨率仍然是挑战。该研究项目将采用新的高级X射线测量值来评估从微米到厘米的混凝土响应，测试微机械理论的基础假设，并为研究社区提供高保真数据以验证模型。这项研究的结果有望改善混凝土机械响应的预测，并促进对其性质的理解。该研究结果还将用于教授研究生工程课程中的高级概念，并为对STEM职业感兴趣的代表性不足的高中学生提供研究机会。这项研究包括在实验室和同步的实验室机械载荷的机械载荷期间，在微米和clusimens flusimens and contrace and Clastimens and controtitions and consantrron设施的机械载荷过程中，对Micron的压力和压力进行压力和菌株的衍射测量组成。这些测量结果将用于验证和扩展微力学理论，例如Eshelby的包容性和Mori-Tanaka的理论，以及它们在长度尺度上的基本假设。例如，测量值将用于检查用于得出同质材料特性的中间变量的平均纳入应力是否准确，并且个人包容性应力与平均值的程度在多大程度上。这些测量值还将用于检查具有不同水平的微结构改进水平的中尺度建模的准确性，从而解决了与此类模型中必须捕获的长度尺度相关的开放问题。 The outcomes of the project will be a fundamental understanding of stress and strain variability across length scales in concrete, guidance for mesoscale modeling, and high-fidelity datasets for calibration and validation of theories and models used throughout the research community.This award reflects NSF's statutory mission and has been deemed precious of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

项目成果

Examining the micromechanics of cementitious composites using In-Situ X-ray measurements

• DOI: 10.1016/j.ijsolstr.2023.112162
• 发表时间: 2023-02
• 期刊: International Journal of Solids and Structures
• 影响因子: 3.6
• 作者: R. Hurley;D. Pagan;E. Herbold;C. Zhai

On mesoscale modeling of concrete: Role of heterogeneities on local stresses, strains, and representative volume element

混凝土的细观建模：异质性对局部应力、应变和代表性体积单元的作用

• DOI: 10.1016/j.cemconres.2022.107031
• 发表时间: 2023
• 期刊: Cement and Concrete Research
• 影响因子: 11.4
• 作者: Thakur, Mohmad M.;Henningsson, N. Axel;Engqvist, Jonas;Autran, Pierre-Olivier;Wright, Jonathan P.;Hurley, Ryan C.
• 通讯作者: Hurley, Ryan C.