Development of Concrete Damage-Flow Rate Correlation using Integrated Structural Testing and X-Ray Tomography

项目摘要利用综合结构测试和X射线层析技术开发混凝土损伤-流动率相关性Tara C.Hutchinson(PI)1和Falko Kuester 2混凝土是迄今为止在美国使用最广泛的建筑材料，广泛用于我国的建筑、高速公路、隧道、供水和污水系统以及其他基础设施的建设。混凝土的使用寿命强烈依赖于其运输性能，这意味着旨在研究这种内部微观结构的调查应该将这些运输性能与混凝土构件的损伤状态联系起来。在这项建议中，我们试图提高我们对钢筋混凝土构件损伤特性的基本知识，并将这些特性与基本的运输特性联系起来。虽然许多传输机制肯定是感兴趣的，但我们选择透气性作为感兴趣的传输机制，作为迈向其他机制的第一步，并为所提出的方法奠定基础。我们提出的方法包括集成比例试件的结构测试、X射线计算机断层成像(CT)成像和20个钢筋混凝土板式试件的空气流量实验。试件承受单轴和双向加载条件，包括几何参数(高宽比和板厚)、材料细节(配筋率和混凝土强度)和加载细节(轴向载荷和加载方案)的参数变化。对文献中的渗透率和渗漏率公式进行数值评估以及对实验试件进行有限元模拟，以全面努力制定关于钢筋混凝土构件损伤渗漏率相关性的设计指南。智力优势-这一智力优势包括实验方法和结果的发展，对钢筋混凝土损伤-传输关系的基本理解的进步，以及对设计行业的实际影响。这项工作提供的数据集(图像和数字数据)将刺激对这种复杂的复合材料内部损伤分布的新发现。最终，这项工作将产生设计指南，说明混凝土渗透性的退化。混凝土研究的整体进展将导致新基础设施和现有结构修复的成本降低，同时延长我们最常用的建筑材料之一的使用寿命。广泛影响-更广泛的技术影响包括促进我们对混凝土作为基本建筑材料的理解，从而导致改进设计，对性能和性能进行更可靠的估计。X光CT系统的获得和实施将对加州大学欧文分校的研究活动、其学生和教职员工以及对使用该系统感兴趣的当地学术界产生深远的影响。数据、图像和数字数据的教育影响，为从普通公众到K-12，特别是多样化和/或少数族裔学生的所有感兴趣的学生提供了一个天然的避风港。这些作品的自然数字特性使其能够在互联网上传播，我们计划设计一个专门的网站(我们称之为ConcretePedia)，专门以VRML格式传播这些图像数据集(供一般公众互动查看和学习)。这项工作还积极参与行业和政府的合作，这有助于促进其对工程公众的影响。

Project AbstractDevelopment of Concrete Damage-Flow Rate Correlation using Integrated Structural Testing andX-Ray TomographyTara C. Hutchinson (PI)1 and Falko Kuester2Concrete is by far the most widely used building material in the United States, with extensive use in the construction of our Nation's buildings, highways, tunnels, water supply and sewage systems and other infrastructure. The strong dependency of the service life of concrete on its transport properties means that investigations, which are geared at studying this internal microstructure, should link these transport properties to damage states of the concrete component. In this proposal, we seek to advance our fundamental knowledge of the damage characteristics of reinforced concrete members and link these characteristics with a fundamental transport property. Although many transport mechanisms are certainly of interest, we select the air permeability as the transport mechanism of interest, as a first step towards other mechanisms and to lay the foundation of the methodology proposed. Our proposed approach includes integrating structural testing of scaled specimens, X-ray computed tomography (CT) imaging, and air flow rate experiments of 20 model reinforced concrete panel-style specimens. Specimens are subjected to uniaxial and biaxial loading conditions, and include parameter variations of geometry (aspect ratio and panel thickness), material details (reinforcing steel ratio and concrete strength), and loading details (axial load and loading protocol). Numerical evaluation of permeability and leakage rate formula available in the literature as well as finite element simulations ofthe experimental specimens will be conducted in an overall effort to develop design guidance regarding the damage leakage rate correlation of reinforced concrete elements.Intellectual Merits - The intellectual merits of this include developments in experimental methods and results, fundamental advancements in the understanding of damage-transport relations of reinforced concrete, and practical impacts on the design industry. The datasets available from this work (both image and numerical data) will spur new discoveries of the internal damage distribution of this complex, composite material. Ultimately, this work will result in design guidance, which accounts for the degrading permeability of concrete. Progress overall in concrete research will lead to a reduction in the cost of new infrastructure and rehabilitation of existing structures, while increasing the service life of one of our most abundantly used construction materials.Broader Impacts - Broader technical impacts include the advancement of our understanding of concrete as a fundamental building material, thus leading to improved designs, with more reliable estimates of properties and hence performance. The acquisition and implementation of the X-ray CT system will have long reaching impacts on the research activities at UC Irvine, for its students and faculty, as well as the local academic community interested in using the system. The educational impacts of the data, images and numerical data, provide a natural haven for reaching all ranges of interested students, from the general public to K-12, and especially the diverse and/or minority student. The natural digital nature of this works makes it viable for Internet dissemination, and we plan to design a special web site (we termed ConcretePedia) devoted to disseminating these image datasets in VRML format (for the general public tointeractively view and learn). This work also actively engages industrial and government collaboration, which helps facilitate its impact to the engineering public.