CAREER: Pickering Stability of Air Bubbles for Superior Air-Entrainment and Frost Durability of Cementitious Materials

This Faculty Early Career Development (CAREER) award will support research that focuses on solutions for improved concrete sustainability that are urgently needed to combat climate change. While global reductions in CO2 emissions are necessary, CO2 emissions from cement production have increased 1.5% per year from 2015-2021. Two thirds of the global increase in greenhouse gas (GHG) emission in 2019 were attributed to cement production. Improving the durability of new concrete structures is a critical strategy for reducing GHG emissions. Although proper air entrainment is critical for concrete frost durability, conventional air entrainment methods are often ineffective in modern-day mixes. As concrete technology continues to develop at a rapid rate, and as novel alternatives to traditional concrete emerge, a more robust air entrainment solution is needed; one that can overcome known adverse interactions and can be adapted for increasingly complex systems. This work will explore the hypothesis that Pickering stabilization can be used instead of/in addition to current air entrainment approaches for exceptional bubble stability and size control, accelerating adoption of low-carbon building materials without sacrificing their long-term durability and thus sustainability. This research will be integrated into a K-12 education/outreach (EO) program to enrich research, education, and outreach experiences simultaneously. The goal of the EO plan is to develop a diverse, research-literate workforce that can leverage their unique experiences and perspectives to introduce creative, impactful solutions for change. This work will develop the workforce by building a diverse pipeline through a research-integrated K-12 education and outreach program, an undergraduate/graduate training program focused on best practice in inclusive pedagogy and community building, and an annual concrete career week that will introduce grade 8-12 students to hands-on research experience from the work and 5 other concrete career options via facility tours with industry professionals. The project will use molecular dynamic (MD) simulations and experiments to test the hypothesis and develop a fundamental model to describe the mechanisms controlling Pickering stabilization of air bubbles in cementitious systems. The main goal of the research-education activities is to develop a strong integrated program focused on developing air-entrainment solutions via Pickering stabilization, while advancing the STEM workforce in research literacy, diversity, and inclusion. This work will provide a missing, but essential foundation for improving the frost durability of concrete structures, transforming the way the industry entrains air in concrete from trial-and-error empirical practices to systematic, controlled, and predictable air entrainment via exploitation of fundamental principles. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.