Florida International University (FIU) (Miami, Florida, USA) received a $3.2 million grant from the U.S. Army Corps of Engineers (Washington, DC, USA) to research the 3D printing of Ultra-High Performance Concrete (UHPC). This innovative research looks to help military personnel and industry professionals create extra-strong, customized structures on demand.
UHPC, a material stronger and more durable than traditional concrete, is projected to become very important to the construction industry in the coming years, according to Atorod Azizinamini, director of infrastructure research and innovation at the Office of Research and Economic Development and professor of civil engineering at the FIU College of Engineering and Computing.
“Just a shell of UHPC wrapped around a structure adds to its total strength,” says Azizinamini, principal investigator of the grant. “The properties of UHPC allows us to make structures smaller and more lightweight. This translates to energy savings and smaller carbon footprints.”
Another major benefit of UHPC is that it is difficult for water to penetrate. This is important because if a substance like saltwater breaches through a building’s concrete and reaches its reinforcing steel, it can cause corrosion.
“The idea of having really high-quality concrete is that you increase the time it takes for chloride in water to penetrate the concrete and reach the steel,” says Kingsley Lau, an associate professor in the Department of Civil and Environmental Engineering and co-principal investigator of the grant.
By 3D printing UHPC, someone can theoretically create custom, elaborate construction pieces simply by sending a file to a machine. For example, military personnel in the field could print support beams for bridges or a construction worker in a remote area could print a reinforcement piece for a building. All that would be needed is the UHPC material, a printer, and a design.
The challenge with printing UHPC, however, is that each layer begins to solidify as it is laid down, similar to how a sidewalk is gelatinous before it hardens. As layers of concrete are stacked in a printed design, inconsistencies can form at the seams.
FIU’s research will concentrate on determining what exact chemical compositions of UHPC best prevent these vulnerable seams from forming. The professors will come up with recommendations for three types of 3D printing: printing layers, spraying layers, and a new extrusion type of printing that FIU is patenting. Having a specific “ingredient list” for UHPC will also help with the fact that concrete is often locally sourced, and its chemical composition can change from place to place.
The grant was secured with the support of members of Congress.
“This is an important investment by the Army Corps towards Florida International University, which will help maintain our defense readiness while further advancing innovation and creating jobs for our workforce in Florida,” said U.S. Rep. Mario Diaz-Balart, ranking member of the Transportation, Housing and Urban Development appropriations subcommittee of the U.S. House of Representatives.
The research comes at a time when UHPC is becoming more affordable and practical to use. Azizinamini estimates that a cubic yard of the material is selling at less than 10% of the price of when it was first commercially released. Building design specifications around UHPC are also being developed. FIU’s research looks to unlock a new wave of advancements around this emerging construction material.
“I am so proud to support the innovative solutions that FIU is developing, which will help ensure our coastal installations are more resilient,” says U.S. Rep. Debbie Wasserman Schultz, chairwoman of the Military Construction and Veterans Affairs subcommittee of the House Appropriations Committee.
Source: FIU News, https://news.fiu.edu.