Recycling rooftops into roadways

MoDOT uses unlikely ingredient in asphalt

News Missouri Department of Transportation July 16, 2007
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The Missouri Department of Transportation is among the first state agencies in the nation to recycle tear-off shingles to resurface or rebuild highways.

Over the past two years, MoDOT has allowed contractors to put used shingles that have been removed from rooftops into their asphalt mix. The result is a very durable, more-rut resistant asphalt at a much lower price.

“MoDOT embraces new ideas that not only help us become a more cost-efficient agency, but a more environmentally friendly one, too,” said Director Pete Rahn. “By recycling asphalt shingles, we keep them out of landfills, preserve petroleum resources and lower our construction costs while maintaining high quality asphalt pavement.”

The use of recycled shingles saves $3 to $5 per ton of asphalt. That may not sound like much at first, but consider this: a typical resurfacing project would use about 30,000 tons of asphalt, for a savings of $90,000 to $150,000.
Beyond the cost savings, this practice also helps MoDOT in its efforts to be environmentally responsible. According to the Missouri Department of Natural Resources, an estimated 146,500 tons of roofing materials are disposed of in Missouri landfills each year. By reusing tear-off shingles, the department reduces the amount that ends up in landfills.

Shingle recycling also helps MoDOT reduce the amount of petroleum it uses in its road construction program. By using recycled asphalt shingles, the department reduces the amount of liquid asphalt in a mix design by 20 percent to 25 percent.

“MoDOT has incorporated a variety of waste materials on roadways,” said Joe Schroer, field materials engineer. “However, we are on the cutting edge nationally for our efforts to reuse roofing shingles.”

MoDOT is working with other agencies and organizations nationally to refine the specifications for the use of asphalt shingles as a hot-mix asphalt material.

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