Repaving of the runway at Renton Municipal Airport is under way after crews late last week used big grinding machines to remove the old layer of asphalt.

The repaving will go on around the clock through Aug. 9, when crews will cut grooves perpendicular to the runway to help planes brake in wet conditions.

The project costs about $4.3 million, the bulk of which is coming from a grant from the Federal Aviation Administration. Five percent of the money for the project – about $219,000 – will come from revenues generated from airport operations.

Motorists traveling near the airport are seeing a steady stream of trucks carrying asphalt to the runway.

Typically, a runway is repaved every 20 years or so. The Renton runway was last repaved in about 1988.

The asphalt covers about 4,200 feet of the 5,380-foot runway. The rest is concrete. Some repairs are planned to the concrete, which lasts much longer than asphalt.