A new kind of concrete called Ductal will allow bridges to hold more weight and last longer. Made of a mixture of sand, cement, water, and small steel fibers, it is 10 times more expensive than traditional materials but also stronger and virtually impermeable, helping bridges become more durable. AMES, Iowa--Bridges take a beating, and it can really break the bank to repair them. Now, researchers are breaking bridges to learn how to build them better and save you money. Justin Doornink spends his mornings underneath bridges. He's an engineering student and, as part of his homework, he's installing sensors to measure the impact of traffic on the bridge. He's trying to figure out how to strengthen the structures. One option is ultra-high-performance concrete, which is made from sand, cement, water and small steel fibers. Brent Phares, a civil engineer and associate director at the Iowa State University Bridge Engineering Center in Ames, says, "It's much, much stronge...
