Rubber tires met a road of rubber for the first time in Oro Valley Monday when the town began repaving a nearly two-mile stretch of Rancho Vistoso Boulevard from Oracle Road to Big Wash with rubberized asphalt.
The experimental project incorporates new technology first introduced in Europe and later refined by a Phoenix engineer. The technology has since been used worldwide, said Bob Kovitz, Oro Valley spokesman.
The Rancho Vistoso Boulevard road work, two lanes each way, is being done by Southern Arizona Paving Co. at a cost of about $370,000 .and is scheduled for completion this week.
The rubberized asphalt, a mixture of crumb rubber particles derived from the grinding of waste tires and paving grade asphalt, is expected to substantially reduce road noise, cut paving costs and delay the need for repaving again for years, said Oro Valley Engineering Division Manager Paul Nzomo.
"It's never been done in town before," Nzomo said. The noise reduction the asphaltic rubber produces varies from site to site, but town officials expect it will lower noise levels by from three to 10 decibels, or as much as 90 percent. If that proves true, the rubber surface may be applied townwide, he said.
Nzomo said the effect would be like the driver of a new car pulling out of a car lot and wondering if the engine was running because it was running so quietly
In terms of lower maintenance costs, on roads renovated using asphaltic concrete, a recoating is usually required about every five years and a complete reconstruction has to be done about every 10 years, Nzomo said.
Using the asphaltic rubber, town officials don't expect to have to do any major work for from 12 to 17 years, substantially lowering costs even after accounting for the higher cost of the rubberized asphalt initially, Nzomo said.
An estimated 5 million waste tires are produced annually in Arizona, of which about 75 percent are reused for road surfacing, according to the Arizona Department of Transportation. The Rancho Vistoso project will entail using the equivalent of about 4,000 waste tires.
The elastic nature of the rubberized asphalt also means less cracking and construction time will be shortened as well, reducing paving crew exposure to traffic, Kovitz said.
The work is being paid for out of state highway user revenue funds. Two inch layers of asphaltic concrete are being stripped away from two lanes each way along Rancho Vistoso Boulevard and replaced with the rubberized asphalt.
The road work also will include replacing curbs, striping and pavement markings. The entire project is expected to take about a month, Nzomo said.
Another advantage of the rubberized asphalt is that it eliminates the need for building sound wall abatement structures along roads and highways which can cost more than $400 a linear foot, compared with the $12 per linear foot of the rubberized asphalt, Kovitz said.