The city has contracted with Intermountain Slurry Seal, Inc out of Sparks, to fix the streets whose chip seal has failed since the installation in September last year, reported City Manager/Engineer Steve West.
“The installation techniques used by the contractor during construction were excellent,” said West, “so it is our conclusion that the failure of the chip seal had to be due to a problem with the asphalt mix (ie the combination of oil and aggregate).”
Since a substantial portion of the aggregate has been stripped off of the asphalt mat, the contractor is recommending that a micro-seal be installed after heavy sweeping of the chip seal, explained West.
“Our thought was that they could take steel brooms and put a lot of pressure on it and take off the rest of it and then start over,” said West, “but realistically you are going to damage a lot of the good that you’ve already done. Because before they put the rock on, they put a pretty thick layer of oil, and that’s still there. If you can save that without grinding that off with the brushes you’ve still got a better protection for your street underneath. So we think if it’s swept really good first and then they put the micro seal on it should blend everything just fine.”
West explained that micro seal is commonly used to smooth out the unevenness of streets. It’s a finer material, said West, and doesn’t have the grains or aggregate that chip seal has. It will look more smooth, said West, and won’t have the same friction as chip seal so it’ll be a little slicker when wet.
“We anticipate that the resulting micro-seal will have at least an equal life, and perhaps a longer life, than a typical chip seal,” he said.
West said he has always wanted to try micro seal. “It’s got a really good reputation on collector street life. This will be great to see how that lasts, because we’ve been trying to decide whether to keep chip sealing our collector streets or using micro seal. This will give us a good comparison.”
The project is tentatively set to start in May, said West; micro seal requires the temperature to stay pretty warm.
The original asphalt rubber chip seal project done in September 2014 cost the city $719,918 and cost the county $356,545, said West. When it was obvious the chip seal had failed, West said, the city and county had withheld their payment on the project. The micro seal will come at no additional cost to the city or county, said West.
