Pavement with potential

News August 15, 2003
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Though Maryland's eastern shore is only 100 miles from downtown Washington, D

Though Maryland's eastern shore is only 100 miles from downtown Washington, D.C., it appears to be a world removed. Small towns and farmland recall an earlier time when the biggest problem facing highway engineers was how to keep cars from backing up behind a slow-moving tractor.

For most drivers passing through the area, those fields and roadside stands are just a blur on the way to or from the beach. Maryland's oceanfront resorts attract millions of visitors every year.

The Maryland State Highway Administration (MDSHA) has just completed a project designed to eliminate a major bottleneck on that well-traveled route: the U.S. Rte. 50 Salisbury Bypass. The divided, four-lane, seven-mile bypass connects U.S. Rtes. 13 and 50. By routing traffic around the heart of Salisbury, Md., the bypass, in the words of then-Governor Parris Glendening, is "giving Main Street back to the citizens of Salisbury while providing a safer, more convenient trip to the beach."

Completed three months ahead of schedule, the bypass opened in the spring of 2003 and has won awards from the American Concrete Institute, the American Society of Civil Engineers and the American Road and Transportation Builders Association.

This low-lying coastal region of the eastern shore, situated between the Atlantic Ocean on the east and Chesapeake Bay on the west, is exposed not only to typical freeze-thaw cycles of the Mid-Atlantic region, but also exposure to salt air. The bypass is heavily traveled, especially in the summer months, and handles a significant amount of commercial traffic.

In addition to providing a quicker route to the beach, the bypass reduces congestion for local residents. Before the bypass was completed, the route through downtown Salisbury included 16 traffic signals. Now motorists go through only two traffic lights east of the city.

The Salisbury Bypass offers another, less visible benefit: It will provide hard data to help engineers evaluate the potential of high-performance concrete for highway pavements.

Buried beneath the new pavement, an array of sensors collect information on three segments of the highway: a control segment using a traditional pavement mix and two test segments using high-performance concrete. The data, to be collected over a two-year period and analyzed at the Civil Engineering Department of the University of Maryland, will provide good estimates of how long these high-performance pavements will last under actual conditions.

Vicki Stewart, statewide concrete/chemical/cement team leader for the state of Maryland, said that MDSHA is keenly interested in researching high-performance concrete pavements. "The potential savings to the state from extended-life pavements are enormous. These data will allow us to develop solid life-cycle cost analyses of these pavements. We'll be able to quantify the benefits in real dollars. And, they'll allow us to evaluate and compare the performance of different approaches."

For more on the story, read the September issue of ROADS & BRIDGES.

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