Shape Memory Polymer Can Serve as Sealant.

• Position: ROAD REPAIR

As any driver knows, going from point A to B in an automobile can make for a rough ride. Many roads are full of potholes and cracks and in need of repair. A number of factors go into creating these craters and cracks in the concrete--climate, weather, and traffic, mainly.

Looking to fill the gap, so to speak, is Guoqiang Li, professor of mechanical engineering at Louisiana State University, Baton Rouge. His team's work with a shape memory polymer potentially will save not only the state's roads, but money and time.

"This problem of cracking in pavement has existed for more than 100 years. No one can control it, so you must have a good sealant. We propose a sealant that behaves thermally opposite to common physics."

As concrete freezes and shrinks, Li's polymer sealant expands to fill the cracks. When the concrete heats up and expands, the sealant...