CAREER: Linking Pore Structure, Performance, and Material Design of a Sustainable Macroporous Concrete for Multifunctional Applications

增孔混凝土(EPC)是一种相对较新的混凝土，具有比普通混凝土更高的孔隙率和孔连通性，从而有利于暴雨径流控制和公路噪声缓解等应用。这份职业计划的基本目标是通过涉及体视学方法、断裂特性、多孔介质流动和数学优化的多学科方法，将EPC的孔结构特征和性能与其材料设计参数联系起来。来自二维消失模铸造图像的几何数据将利用随机几何进行立体解释，并开发了一种基于颗粒填充理论的新的孔隙率预测方法，以建立材料设计参数与孔结构特征之间的关联。孔结构特征将与：(I)使用同时涉及韧性和强度的断裂准则的力学行为，从而提供对裂纹钝化和更高的空隙分数之间竞争的理解，(Ii)使用X射线层析成像、平面图像的三维重建和分形模型的渗透率，以及(Iii)使用多相流理论和重建模型的污染物滞留效率。由于EPC系统需要针对多个性能要求进行设计，因此将使用多目标优化程序来获得可行的材料设计参数集。这将有助于通过孔结构特征来发展材料设计和性能之间的关系。这项职业计划将为EPC系统带来急需的基于性能的设计方法，并使性能预测成为可能。这将有助于开发确定EPC性能的测试方法，并将促进EPC设计从目前采用的试错法向科学过程的过渡。该提案中的教育计划通过基于问题的设计和学习、教学实验室课程的开发和K-12推广计划与研究部分紧密联系在一起。学生将使用构思-实施-设计-操作(CDIO)的方法来实施基于问题的学习和设计，学生将负责设计、构建和评估几个小型EPC试验台系统。将开发一门教学实验室课程，本科生可以在其中对与水泥基材料相关的结构化主题进行研究。克拉克森现有的GK-12项目将作为一种媒介，以EPC为模型多孔工程材料，向中学生强调动手活动和解决工程问题，从而整合研究和推广。

Enhanced Porosity Concrete (EPC) is a relatively new class of concrete having higher than normal porosity and pore connectivity, thus facilitating applications such as storm water runoff control, and highway noise mitigation. The fundamental objective of this CAREER proposal is to link the pore structure features and performance of EPC to its material design parameters through a multi-disciplinary approach that involves stereological methods, fracture properties, porous media flow, and mathematical optimization. Geometrical data from two dimensional EPC images will be stereologically interpreted using stochastic geometry, and a novel porosity prediction method based on particle packing theory developed to establish correlations between material design parameters and pore structure features. Pore structure features will be related to: (i) mechanical behavior using a fracture criterion that involves both toughness and strength, thus providing an understanding of the competition between crack-blunting and higher void fraction, (ii) permeability using X-ray tomography, three-dimensional reconstruction of planar images, and fractal models, and (iii) pollutant retention efficiency using multi-phase flow theories and reconstructed models. Since EPC systems need to be designed for more than one performance requirement, a multi-objective optimization procedure will be used to arrive at a feasible set of material design parameters. This will facilitate the development of relationships between material design and performance through the pore structure features. This CAREER proposal will result in a much needed performance-based design methodology for EPC systems, and enable predictions of performance. This will aid in the development of test methods to determine EPC properties, and will facilitate the transition of EPC design to a scientific process from the currently employed trial and error methods. The educational plan in this proposal is strongly tied with the research component through problem-based design and learning, development of a teaching lab course, and K-12 outreach program. A conceive-implement-design-operate (CDIO) approach will be used to put the problem-based learning and design into practice where the students will be responsible for designing, constructing, and evaluating a few small EPC test bed systems. A teaching lab course, where the undergraduate students can do research on structured topics related to cement-based materials will be developed. The existing GK-12 program at Clarkson will be used as a vehicle to emphasize hands-on activities and engineering problem solving to middle and high school students using EPC as a model porous engineering material, thus integrating research and outreach.