Everything Old is New Again
OTIA III State Bridge Delivery Program Emphasizes Recycling
The Oregon Department of Transportation has developed a unique series of intiatives that encourage recycling on all levels of the OTIA III State Bridge Delivery Program. Through these initiatives, contractors are reusing and recycling products used for bridge construction and repair. The result of ODOT’s commitment to recycling is savings in cost and time, and the protection of needed resources.
On a project in Klamath Falls, ODOT is recycling more than 10,000 tons of debris from two bridges slated for replacement. On U.S. 20 between Bend and Ontario, the agency is reusing asphalt to pave bridge approaches. And ODOT has developed an initiative for the use of industrial waste -- which has no intrinsic value whatsoever -- to develop products that strengthen bridges, making them more durable.
Oregon. The OTIA III State Bridge Delivery Program is the largest state investment in Oregon highways and bridges since the interstate freeway system was built in the 1950s and ’60s. During the next decade, ODOT will repair or replace hundreds of aging state highway bridges across Oregon. The widespread construction will create new jobs and encourage economic growth throughout Oregon.
Eugene, for example, won contracts to demolish the California Avenue and Greensprings Drive bridges in Klamath Falls to make way for the construction of new bridges in this vital part of the U.S. 97 corridor. Under its contract, Staton has salvaged all the concrete aggregate and rebar materials from the demolition activities. The concrete and rebar are taken back to the company’s central plant and recycled.
Already, Staton has taken about 2,400 tons of concrete aggregate materials from the California Avenue and Greensprings Drive bridges. The materials were crushed into 1-inch particles and used as gravel. Of the 2,400 tons of aggregate salvaged and processed into gravel, 500 tons were reused on the Klamath Falls site as fill and to pave an approach road.
The rebar is cleaned of all the concrete, melted down, and resold. With steel prices on a steady rise over the past decade, scrap metal -- particularly the grade used in rebar -- is a valuable commodity. In total, Staton has recycled about 250 tons of scrap metal from the Greensprings Drive Bridge, and it expects to salvage an additional 250 tons during the second phase of demolition. Additionally, the contractor expects to recover 500 tons of scrap metal from the California Avenue site.
“These demolished bridges are 100 percent recyclable,” said Ron Richey, estimator and supervisor for Staton Cos. “Simply crunching, loading, and hauling doesn’t save money anymore. In fact, the cost of hauling the aggregate and steel to a landfill is $50 a ton, not including the cost and additional pollution of trucking it to a landfill site. Sorting and recycling is truly where the value is. And it’s ultimately better for the environment to reuse source materials or find other alternatives to dumping the debris in a landfill.”
ODOT also is at the forefront of recycling advancements in the production of high-performance concrete. The agency uses industrial by-products to strengthen the blend of Portland cement, water, and sand. On projects on U.S. 20 near Burns, for example, ODOT is using a blend of micro-silica and fly ash in the dry mix of concrete. Micro-silica comes from the smoke generated during the production of silicon computer chips. Fly ash is collected from the smoke made when coal is burned.
Though these products have absolutely no value in their natural state, they make concrete mixes much stronger and less permeable to water. The result is concrete bridge decks that are denser; more resistant to the corrosive effects of water, ice, and anti-icing chemicals; and strong enough to support heavy truck traffic.
“We are taking industrial waste products that are of no use to one industry and making them a critical component for another industry,” said Randy Kessler, ODOT’s concrete quality coordinator. “The use of these new, stronger blends of concrete means the roads and bridge decks will last much longer.”
Although the opening of a new bridge, or the use of an exciting new technology in bridge construction, may be an impressive public display of the success of ODOT’s bridge program, the advancements in recycling are equally important. By encouraging recycling, the agency is demonstrating its dedication to positive environmental stewardship. Across the state, ODOT and its contractor partners are taking things that are old, tired, and wasted and making them new and useful again.
”Recycling is an exciting part of ODOT’s bridge program,” Catron said. “We are reducing waste, saving time, saving money, and, in the process, streamlining production and creating stronger bridges.”
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