Old tires may just end up on your street – in the asphalt that is.
Manteca is continuing to use asphalt overlays with a 20 percent mix of crushed and diced up tires as it repairs streets.
The first streets to go with the rubber chip seal mixture was in 2008. They were a half mile section of Cottage between Yosemite Avenue and the Highway 99 overcrossing, about a half mile of Center Street between the Union Pacific Railroad crossing and Union Road, as well as Industrial Park Drive between Bessemer and Main Street.
While its being touted as a new trend in California, its old hat in Arizona where the rubberized chip seal has been used for the past 20 years to prolong the life of state freeways and surface streets in Phoenix. Arizona officials have pointed to it as an effective way to rid that state of old tries that are difficult to recycle and can’t be buried in landfills due to their inability to decompose in a relatively reasonable amount of time. But recently studies have shown the 20 percent tire rubber mixture combined with liquid asphalt also is reducing vehicle noise by as much as four decibels.
Research cited by the Arizona Department of Transportation shows reduction in noise levels of 50 to 75% is commonly attained.
Arizona transportation officials have also noted that the rubber overlay also is more durable and skid-resistant than conventional asphalt plus provides a smoother ride.
Tires used in the process have their casings, fabric and steel taken apart and the rubber is ground to the consistency of ground coffee.
A one-inch rubberized asphalt concrete (RAC) chip seal uses about 1,500 tires per lane mile of paving. That meant upwards of 9,000 tires were recycled to create the coating to resurface the three Manteca streets.
The initial rubber tire overlay was made sweeter for Manteca as the city received $1 for every square foot of RAC chip seal used in the project under a program instituted by the California Integrated Waste Management Board as a one-rime incentive to encourage cities and counties to use the surfacing material.
The grant reduced the $336,000 cost of the paving projects to Manteca taxpayers by $57,200.
Reducing costs - if possible - for pavement overlays is critical for cities including Manteca.
Manteca had 91 miles of streets in mid 2009, up from 171 miles in 2003.
Typically, streets need to have an overlay at 20 to 24 years to extend their life. In Manteca’s case, the use of RAC chip seal could mean that 560,000 used tires could be used over the course of two decades.