By Bill Sheets Herald Writer
MUKILTEO — It became an issue in last year’s mayoral race: gravel coming loose from repaired sections of Mukilteo streets, making for bumpy rides and grumpy drivers.
Then-candidate and city Councilwoman Jennifer Gregerson said she’d do something about it if she were to be elected mayor.
Now, Mayor Gregerson says she’s keeping that promise, announcing that the city will try a different way of fixing aging sections of asphalt.
The city plans to apply “bonded wearing course,” or BWC, to sections of 88th Street SW and 92nd Street SW this summer as a pilot project.
City officials are scheduled to discuss the new method, and street maintenance in general, at a public meeting set for 6 p.m. Monday at Mukilteo City Hall, 11930 Cyrus Way.
The BWC technique involves applying a layer of gooey, petroleum-based polymer to the roadway and spreading a layer of hot asphalt on top.
The previous method, chip seal, also starts with the petroleum polymer but employs raw gravel on top instead of asphalt. The rocks eventually can loosen and separate from the bottom layer, Mukilteo public works director Rob McGaughey said.
In the bonded wearing course method, the steaming asphalt draws the polymer upward to permeate the asphalt and bond the two layers together, he said.
“The ride will be smooth, it won’t make as much noise, there won’t be any rocks that pop off,” McGaughey said.
The tradeoff is that BWC costs about twice as much as chip seal — $7 to $8 per square yard compared to $3.50 to $4.
The city plans to apply BWC to 88th Street SW from 44th Avenue W. to 60th Avenue W. and on 92nd Street SW from 44th to the Mukilteo Speedway. The work is expected to cost a combined $150,000. The two streets were next in line to be chip sealed.
On the upside, the BWC method lasts twice as long as chip seal — 15 to 20 years compared to seven to 10, depending on traffic and roadway condition, McGaughey said.
Full roadway repaving is more involved, costs about $15 per square yard and lasts longer, up to 30 years, he said.
Cash-strapped cities have increasingly turned to chip seal in recent years as a low-cost alternative to repaving, according to McGaughey.
“Cities have not been doing street maintenance, they’ve been deferring it,” he said. “The roads are starting to fall apart and show the wear from non-maintenance.”
Bonded wearing course is basically a cross between chip seal and full repaving, said Nick Barrett, area sales manager for Telfer Oil in Martinez, Calif. The city of Mukilteo is hiring the company to help with the project.
“You’re getting the best of both worlds,” Barrett said.
California roadways where BWC was applied back in 1998 are still performing well, he said.
The BWC method is little used in Western Washington, partly because of the short paving season here, McGaughey said. It takes special equipment, and few contractors here, if any, know how to do it.
Telfer Oil either will come up and do the paving itself or loan the equipment to a local contractor and provide assistance, Barrett said.
“Our goal is to keep the local people up there on the ground working,” he said.
Public response to the work on the two streets will help determine whether to continue the method in the future, city officials said.
“We need to look at the long run when we assess how we take care of our streets for the next 10 to 20 years,” Gregerson said.
Bill Sheets: 425-339-3439; firstname.lastname@example.org.