‘BEST KEPT SECRET IN MIAMI’
FIU lab makes stronger, better concrete
At a little-known lab at Florida International University, a professor is studying ultra-high-performance concrete’s effect on improved construction safety,
In a corner of Florida International University’s engineering campus, a constant mechanical pulsing echoes through a warehouse that smells like a construction site.
The rapid “hum hiss” is coming from the hydraulic pistons that are dropping — then lifting — hundreds of pounds of weight off a chunk of concrete the size of a dining room table. A computer screen keeps track of the results with a red line on a graph and steadily increasing green numbers. It’s part of an experiment testing a newer, better form of concrete.
The professor behind the lab calls this warehouse “the best-kept secret in South Florida.”
Atorod Azizinamini, a professor of civil engineering and director of Moss School of Construction, Infrastructure and Sustainability at FIU, studies ultra-high-performance concrete (UHPC). The unique blend of materials, including shreds of superstrong steel, is about five times stronger than regular concrete.
That makes it much more difficult for rust to creep its way through the concrete and weaken the steel rebar inside. That process, known as corrosion, is enemy No. 1 for coastal condominiums and bridges. Azizinamini said water moves through UHPC thousands of times slower than through regular concrete.
“If we have a building that we know during king tide salt water pools in the basement, it’s better to cover that area with this material,” he said.
UHPC, as the researchers call it, is far stronger than regular concrete, but the real benefit is how flexible it is. Concrete that can bend without breaking makes stronger, safer bridges and condos.
It’s also about three times more expensive, a deterrent for cost-conscious developers.
“But you don’t have to use too much of it, and when you use it, you bring the structures to an even better condition than they were before,” Azizinamini said.
The ongoing experiment in the Titan America structures lab is testing exactly that. Researchers applied a thin layer of UHPC to a piece of concrete, and now they’re simulating the daily load of people entering and exiting a condo building. With this machine, they can simulate years’ worth of action in weeks, and then check to see how well the UHPC is sticking to the regular concrete.
Azizinamini said the material is popular in Europe and has caught on in the last six or seven years among bridge builders, including for two recent bridges built in Deerfield Beach and West Palm Beach.
“But for some reason, the building folks haven’t got into it,” he said.
“Some people don’t even know that it exists, and one of the best places that is conducting that kind of work is right here at FIU.”
The warehouse also contains a 3D printer with which researchers are trying to perfect the technique of automatically printing construction parts with UHPC. It’s smallscale in the lab, but if it works, larger printers might be able to churn out things like beams or posts cheaper, easier and faster.
Outside, 2 x 4 wood plank squares covered in chicken wire show the results of another potential application of the concrete — applied by spraying rather than being poured from a concrete mixing truck.
These projects and more are currently funded almost entirely by the federal government, Azizinamini said, so that’s been the focus of their work.
But he’d like to see more local attention given to this new form of concrete, especially from home and condominium developers.
“It gives me heartburn, a little bit,” he joked. “Because I think there’s a lot of potential for this material, especially in light of the recent collapse in Surfside.”