| OTIA III State Bridge Delivery Program |
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| Web Brief (Mar 08) |
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ODOT recycled asphalt from this I-5 paving project
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For ODOT, asphalt is the black gold of recycling
Most of us are used to recycling, whether by collecting our deposit when we return a pop can to the grocery store or bundling our newspapers to be picked up at the curb. As the saying goes, “Every little bit helps.”
The asphalt paving industry, however, is doing more than just a little bit, recycling more than 73 million tons of the approximately 90 million tons of asphalt pavement produced in the U.S. annually. In addition, with the price of aggregate and petroleum rising, what’s good for the natural world is increasingly good for the wallet.
Recently, ODOT contributed to the effort to conserve the environment and taxpayer dollars. In the course of replacing two bridges on Interstate 5 near Wilsonville and performing pavement preservation on 22 miles of the six-lane highway, the agency and contractor kept 130,000 tons of pavement in circulation and saved more than $133,000 in landfill fees.
“This section of highway has seen an increase in passenger car traffic and wear and tear from studded snow tires,” said Elizabeth Hunt, engineer and manager of ODOT’s Pavement Services. “We were able to restore the interstate proactively, removing and replacing two inches of pavement while keeping traffic moving.”
As part of the standard operating procedures for ODOT paving projects, contractors hauled away the asphalt pavement removed during the bridge program project and stockpiled it for reuse as reclaimed asphalt pavement, or RAP.
“It’s a sensible, sustainable business practice to reuse materials,” said Bill Relyea, project manager for Oregon Bridge Delivery Partners, ODOT’s management firm for the bridge program. “In addition, the hauling distances are decreased, which saves both money and time.”
The asphalt and aggregate that make up RAP are both valuable commodities. Once the asphalt is melted down, it and the reclaimed aggregate are mixed in with new asphalt concrete, sometimes making up as much as 30 percent of the whole. By using RAP, the contractor avoids the cost of providing all new materials and can pass that savings along to ODOT through reduced prices.
Another environmental benefit of recycled asphalt is that RAP does not leach into water supplies. In fact, drinking water reservoirs are often lined with asphalt, and the Oregon Department of Fish and Wildlife uses asphalt pavement to line fish-rearing ponds.
“ODOT works hard to make cost-effective decisions to maintain our road system in good condition. Well-maintained roads are good for everyone,” Hunt said. “Smooth roads reduce fuel consumption and support heavy loads better. The longer a road lasts, the fewer raw materials we use and the less time motorists spend in traffic congestion while the roads are being rehabilitated.”
The asphalt industry has been recycling on a large scale since the 1970s, when the price of petroleum first skyrocketed. With oil breaking the $100-per-barrel mark in January 2008, RAP continues to be a highly valuable commodity, and ODOT and its contractors are doing all they can to give old pavements new life while protecting public safety.
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