(WSVN) - In the wake of the Surfside collapse, structural engineers are vowing to build better, safer buildings, and everything from super strong concrete to longer lasting rebar is being tested right here in South Florida. 7’s Kevin Ozebek has tonight’s 7 Investigates.
We pay a premium to live where we can feel the ocean breeze and hear waves crashing outside our doors, but building next to salty water and air comes with a price.
Kevin Ozebek: “Are our buildings in South Florida more vulnerable to corrosion?”
Atorod Azizinamini, FIU engineering professor: “Yes, yes, it’s more vulnerable.”
Florida International University’s Atorod Azizinamini and Florida Atlantic University’s Francisco Presuel-Moreno are two engineers focused on fighting corrosion.
Francisco Presuel-Moreno, FAU engineering professor: “We have samples that have been here since the 1990s.”
Outside Francisco’s Dania Beach lab, he has dozens of concrete and rebar samples just sitting here.
Over time, you can see how ocean air and water takes its toll. Once salt and moisture make their way through the porous concrete and reach the rebar, corrosion starts.
Francisco Presuel-Moreno: “The rebars have corroded in such a way the concrete has separated.”
The corroding rebar produces chemicals that then degrade the concrete and cause it to crack.
Most rebar is made of carbonate steel, but Francisco’s experiments show there are better options.
Francisco Presuel-Moreno: “Stainless steel on the top, carbonate steel on the bottom.”
Kevin Ozebek: “Now that is a striking difference here.”
Francisco Presuel-Moreno: “That’s correct, yes.”
Unfortunately, stainless steel rebar is five times the price, though Francisco says concrete mixed with as little water as possible also significantly delays corrosion.
Francisco Presuel-Moreno: “If you have good concrete, and you have a thick concrete cover, you can get structures that last 75 to 100 years before corrosion initiates.”
Atorod Azizinamini: “It’s the most unique way of trying to detect the corrosion.”
At FIU’s College of Engineering, Atorod is perfecting a device that analyzes magnetic fields. It can detect corroding rebar inside concrete.
Atorod Azizinamini: “When you have lost steel, your magnetic field is going to change.”
But to fend off corrosion in the first place, Atorod is studying this.
Kevin Ozebek: “It feels nothing like traditional concrete?”
Atorod Azizinamini: “No, it doesn’t.”
This “super concrete” is mixed with little water, and it is loaded with fine strands of steel.
Kevin Ozebek: “This adds tremendous strength to the concrete?”
Atorod Azizinamini: “It allows the concrete to bend it without breaking it.”
This “super concrete” is also far less porous, so salt cannot easily penetrate it.
Atorod Azizinamini: “We have used it in the bridge industry, but for whatever reason, it hasn’t found its way in the building industry.”
It’s double the price of standard concrete, but Atorod says you need far less of it.
Atorod Azizinamini: “Using this type of material, we can retrofit the building, and the building could be better than the original condition.”
Also, it could be used to construct just parts of a building, like the foundation and balconies, because after witnessing the tragedy in Surfside, building better has never been more important.
Atorod Azizinamini: “We need to take a look at our building codes and all our practices and make changes.”
Both engineers say they would like to see buildings in South Florida inspected more often, and they say, if you notice a crack in your building, do not hesitate to call in an engineer who specializes in spotting corrosion.
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