CAREER: Understanding Behavior and Properties of Nano-Sized Particles in Cement-Based Materials

该学院早期职业发展（Career）奖将研究水泥基材料中纳米颗粒的行为和特性。纳米颗粒有可能导致更致密的材料，并携带特定的功能，导致新的材料设计的可能性，如智能多功能高耐用工程混凝土。这些设计的可能性将允许加强性能控制，并将增加有效解决当前国家老化基础设施的不良状况的潜力，并为未来的基础设施问题做好准备。目前，由于对纳米颗粒在混凝土基体中分散的机制了解有限，阻碍了纳米颗粒在水泥基体系中的全部潜力的释放。这些信息对于理解和提高材料的强度和耐久性至关重要。该奖项支持基础研究，为水泥基体系中纳米颗粒的高质量分散提供所需的知识。透过教育外展活动，我们将透过以下方式产生有意义的影响：a)分享水泥基技术的新知识；b)启发和激励下一代追求科学、技术、工程和数学（STEM），让他们发现自己的创造力潜力；以及c)将不同科学学科的知识联系起来，加强土木工程师、材料科学家和化学家之间的互动。受生物学和生命科学的启发，教育影响的核心是创建粒子分散机制的3D可视化。本职业奖的研究目标是研究和了解纳米级火山灰在水泥基复合材料中的分散机制。该研究的核心假设是，除了提高水泥基基质中聚合物颗粒单元之间的稳定力外，提高聚合物与纳米颗粒（100 nm）之间的化学键能将导致更好的分散质量和基质的致密化。为了实现这一假设，提出的研究被细分为以下五个相互关联的研究目标：1)成分表征，2)聚合物合成和表征，3)颗粒-聚合物界面相互作用，4)纳米颗粒稳定和5)混凝土密度评估。提出了一种多方法研究有趣的复杂色散机制。本研究的主要挑战是隔离互连机制以降低系统复杂性。控制聚合物合成和控制水泥基孔隙溶液的离子浓度是促进分离影响吸附动力学和分散机制的参数的例子。

This Faculty Early Career Development (CAREER) award will investigate the behavior and properties of nano-sized particles in cement-based materials. Nanoparticles have the potential to lead to more dense materials, and to carry over specific functionalities leading to novel material design possibilities, such as intelligent multi-functional highly durable engineered concretes. These design possibilities will allow for enhanced performance control and will increase the potential in effectively addressing the current poor condition of the nation's aging infrastructure as well as prepare for future infrastructure concerns. Unlocking the full potential of nano-sized particles in cement-based systems is currently held back by the limited understanding of the mechanisms by which they disperse throughout the concrete matrix. This information is critical for understanding and improving the strength and durability of the material. This award supports fundamental research to provide needed knowledge for high quality dispersion of nano-particles in cement-based systems. Meaningful impacts will be created through educational outreach activities by a) sharing newly gained knowledge for the advancement of the cement based technology, b) inspiring and motivating the next generation to pursue science, technology, engineering and mathematics (STEM), letting them discover their potential of creativity, and c) connecting knowledge of various science disciplines to enhance the interaction between civil engineers, materials scientists and chemists. Inspired by biology and life science, the centerpiece of the educational impact is creating 3D visualization of particle dispersion mechanisms. The research objective of this CAREER award is to examine and understand the dispersion mechanisms of nano-sized pozzolans in cement-based composites. The central hypothesis is that enhancing the chemical bond energy between polymer and nanoparticle (100 nm) in addition to improving the stabilization forces between polymer-particle units in cement based matrix will lead to better dispersion quality and densification of the matrix. In pursuit of this hypothesis the proposed research is subdivided into the following five interconnected research aims, 1) constituents characterization, 2) polymer synthesis and characterization, 3) particle-polymer interfacial interactions, 4) nanoparticle stabilization and 5) concrete density assessment. A multi-method investigation is proposed to study the intriguing complex dispersion mechanisms. The main challenge of the proposed research is to isolate interconnected mechanisms to reduce the system complexity. Controlled polymer synthesis and controlled ionic concentration of the cement based pore solution are examples of facilitating the isolation of parameters influencing adsorption kinetics and dispersion mechanisms.