Science Scoops: Space-Age Polymer Sprays on Strength
by Stephen James O'Meara
FRP—it's not liquid steel, but it's just as strong and a lot easier to use—just spray it on! Traditionally, bridge repair means long hours spent wrapping broken or weak parts with steel jackets. Meanwhile, traffic is held up for hours…even days. But, FRP (short for Fiber-Reinforced Polymer) could change all that. FRP is a mixture of cloth fibers and a special polymer developed by a Canadian scientist. It doesn't sound like much, but FRP could change the future of engineering.
FRP sprays on wet, and then hardens to make sprayed structures up to two times as strong as steel, and three times more earthquake-resistant.
Where does this super-strength come from? A lot of it, says inventor Nemy Banthia of the University of British Columbia, is in the application technique. Because the fibers and polymers making up the spray are under pressure when sprayed out of the can, they stick better to the surface they hit. And where they hit a surface is just as important: The individual fibers land on a surface in random orientations, providing equal strength in all directions. Of course, it helps that the fibers themselves are made of materials that are seven times stronger than steel!
Right now, FRP is being tested on a 23-foot (7-meter) bridge in Duncan, a town in British Columbia, Canada. Special sensors embedded in the bridge tell Dr. Banthia how the sprayed surface reacts to stress, loads, and earthquake tremors. The results are so promising that plans are already under way to test the spray on longer bridges in Japan, Singapore, and the United States.
But that's not all. Dr. Banthia envisions spraying new bridges, buildings, and other structures with FRP. Offshore oil-drilling platforms could be sprayed to prevent corrosive seawater from eating away at them. Waste-containing steel drums could be protected from leaking their toxic contents into the soil or groundwater, and brand new bridges and buildings could be strengthened against earthquakes. So, while FRP won't ever take the place of iron and steel, it's sure to play a strong “supportive” role in the future of our cities.
- What is FRP, and why is it so strong?
- The article states that some things that make up FRP are stronger than steel. Why do you think engineers do not use FRP instead of steel to build bridges?