A new and thinner asphalt overlay planned for Providence Road and Range Line Street is designed to give drivers a drier road surface and make the roads more pedestrian- and bicyclist-friendly.
The three-quarter-inch overlay will be used in place of the traditional 2-inch overlay. The resurfacing will be the Missouri Department of Transportation’s first use of the thinner overlay in this part of the state.
“This is our first effort with it, so we’ll have to see what we get out of it,” said Bert Maddox, the assistant resident engineer for District 5. The overlay has been used in other parts of the state, including U.S. 50 near Jefferson City.
A 1.86-mile stretch of Providence Road from south of Stadium Boulevard to Business Loop 70 and 0.54 miles of Range Line Street from Rogers Street to Business Loop 70 will receive the overlay. The five- to 10-day project is scheduled to begin in late July or early August; the work will be done after 8 p.m.
The new asphalt has a different composition that allows for better water drainage. Tyler Francis, technical marketing representative for SemMaterials, which provides technical assistance for the overlay to the Transportation Department, said a certain size of rock has been reduced from the mix, allowing some water to percolate through the asphalt.
“The macro-texture of the mix gives (water) the ability to find its way through the air voids of the mix,” Francis said.
Before the asphalt is put down, an emulsion is sprayed on the road to act as a membrane beneath the new layer.
“As water drains down, it hits that membrane and is moved off the road,” Francis said. The mix of rock and layer of emulsion work together to reduce the amount of water on the road.
Enough water can percolate into the asphalt to reduce the water that is thrown into the air by passing vehicles, Francis said. This so-called back spray can limit visibility.
The membrane also acts as preventative maintenance, Francis said, by helping to preserve the pre-existing road structure by keeping water from breaking it down.
The thinner asphalt will also be better for pedestrians and bicyclists by creating a shorter lip on the edges of the roads and around utilities like manhole covers, Maddox said.
The thinner overlay costs less, but has a slightly shorter lifespan. The traditional thicker asphalt overlay costs about $75,000 per mile per lane and lasts about 15 to 20 years under ideal conditions, Maddox said. The new asphalt costs $40,000 to $50,000 per mile, he said. Francis said the life span of the new asphalt is about eight to 12 years.
The new asphalt means the contractor doing the resurfacing will first clean the existing road surface of any petroleum waste, which brings the total cost to $48,000 to $57,000 per mile.