The Future of 3D Printing of Concrete Infrastructure
David A. Lange
Professor of Civil and Environmental Engineering
Director of the FAA Center of Excellence for Airport Technology
University of Illinois at Urbana-Champaign
There has been a surge of interest in 3D printing technology for concrete structures. Researchers around the world are addressing rheology, set control, interfaces, and delivery methods for concrete that is at once fluid enough to flow and stiff enough to hold shape as layers are placed. Our work focuses on the yield stress of granular fluids such as mortar and concrete. Granular fluids exhibit yield stress as a function of particle size gradation, texture, and aggregate volume fraction. We can adjust granular parameters to tune rheological behavior, and use vibration of the granular fluid to momentarily reduce yield stress to facilitate flow and placement. Recycled materials can be used to achieve sustainability goals, and we are learning how to use the fine particle fraction that is usually discarded. The recycled fine particles can be used for controlled low strength materials. New foamed materials make possible extremely lightweight building products, and also open possibilities for engineered materials for absorbing impact. We have studied microstructure of foamed materials using x-ray computed tomography and new mechanical tests. We are also using advanced computer modeling to capture the crushing behavior of foams as well as the flow behavior of 3D printable cement based materials. These advances are examples of the many new opportunities for concrete materials that will open the door to new applications and construction methods.
David A. Lange joined the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign in 1992. His research area is infrastructure materials, concrete microstructure-property relationships, durability, characterization of pore structure, fiber reinforced concrete, foam concrete, self-consolidating concrete, shrinkage/creep, and cracking. He serves as Director of the Center of Excellence for Airport Technology, a research center sponsored by the O’Hare Modernization Program and the Federal Aviation Administration. Lange has published over 200 technical papers and reports, including 90 refereed journal papers. He is a Fellow of the American Ceramic Society. He is also a Fellow of the American Concrete Institute and winner of its Wason Medal in 2003 and 2018. He is President of the American Concrete Institute for 2018-9, and serves on several other ACI committees.