Concrete has been used for several millennium since the Romans built the famous Coliseum. It’s considered the most popular building material in the world. However many of the world’s bridges and highways are literally falling apart. A typical bridge lasts 50 years. Today the average age of U.S. bridges is 42 years. One-quarter of all U.S. bridges are either structurally deficient or functionally obsolete last year by the U.S. Department of Transportation.
Self healing concrete is coming to the rescue! Several methods of concrete healing are being tested worldwide. One method in the U.S. uses microfibers, while other methods in Europe use bacteria. Both methods seem viable and time will tell if either method is successful.
Victor Li, a civil and environmental engineering professor at the University of Michigan, invented a new kind of concrete that hardly ever cracks and can bend too. It can repair itself and reduce the cost of maintaining bridges and roads. When the microfiber composite is stressed, it bends without fracturing. If it does crack, the cracks tend to be less than a human hair. These tiny cracks have the ability to heal themselves.
Dutch microbiologist Henk Jonkers with the Delft University of Technology in the Netherlands, created self-healing concrete using capsules of limestone-producing bacteria. When the concrete cracks, air and moisture trigger the bacteria to begin sealing off the cracks. The bacteria can lie dormant for as long as 200 years, well beyond the lifespan of most modern buildings. Either method costs about three times that of normal concrete, but is estimated to last forever, thus lowering the overall maintenance costs. This is another great use of technology in improving life on our planet.
~ Bob Larson is a technologist and our Marketing Director at 50 Plus.