CAREER: Reaction Mechanisms, Performance Assessment, and Novel Mitigation Tools for Alkali-Silica Reaction in Concrete Structures

This Faculty Early Career Development (CAREER) project will advance the state of knowledge on deterioration mechanisms, damage mitigation, and prediction of service-life performance for concrete structures susceptible to alkali-silica reaction (ASR). The research approach decouples the three fundamental ASR reactions (silica dissolution, gelation, and swelling) and characterizes the thermodynamic equilibrium and kinetics of each reaction as a function of the chemistry (i.e., species concentrations and interactions) and physics (e.g., temperature, pressure, humidity) of the system. This will significantly clarify the reaction mechanisms and the role of aggregate mineralogy and binder compositions, and can lead to developing more efficient ASR inhibiting admixtures, and admixture delivery methods, applicable to new and existing structures. In addition, new testing and modeling tools are developed for rapid and reliable assessment of the ASR risk and for quantitative prediction of the durability performance of concrete containing potentially reactive aggregates. Finally, ASR in emerging alkali-activated concretes is studied which allows improved reliability and market acceptance of these green materials. The project integrates multi-scale experimentation with multi-scale (geochemical, reactive-transport, and performance prediction) modeling to efficiently achieve these research goals. In addition to advancing the ASR science, the findings could be of substantial value in accelerating the synthesis and utilization of new pozzolans, geopolymers, and other high performance silica-based materials.

Alkali-silica reaction continues to be a major durability problem of concrete. The resulting expansion, cracking, and loss of serviceability impose enormous maintenance and reconstruction costs for bridges, pavements, dams, and other civil infrastructure. This project performs hypothesis-driven basic research to support transformative advancements in durability, service-life extension, and as such, sustainability and resiliency of concrete infrastructure susceptible to ASR. Through fostering collaborations with national and international institutes, the project provides state-of-the-art research training for graduate and undergraduate students to become the next generation scientists and engineers. The project's technical components are well integrated with teaching and outreach activities, including (a) implementing cooperative problem-based learning to improve creative thinking and teamwork skills of undergraduate students; (b) development and dissemination of free interactive e-learning modules to familiarize students, faculty, and practicing engineers with advanced materials characterization techniques; and (c) promoting engineering at high school level to attract and engage under-represented students.