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

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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.