Launch Slideshow

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Asphalt recycling gains momentum

Asphalt recycling gains momentum

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    Terex Roadbuilding's TRIPLE-DRUM asphalt plant is proficient at running high percentages of reclaimed asphalt pavement. Photo: Terex Roadbuilding, Oklahoma City

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    Foam stabilized base is in the foreground as a Wirtgen WR 2500 S foams the other side of the rural road. Liquid asphalt from the tanker at right is mixed with water from the tanker at left in the mixing chamber of the reclaimer. Photo: Wirtgen America Inc.

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    E.J. Breneman's cold-in-place recycling train is led by a 4500-gallon tanker carrying emulsified asphalt. Next is a down-cutting Caterpillar 750C milling machine, which creates a 2-inch-minus material and mixes it with 2% emulsion by weight. The material is conveyed into a windrow elevator, which lifts it into the payer in the rear. Compaction and an overlay follow. Photo: E.J. Breneman

Cold recycling using existing resources

Cold recycling is not a new method of rehabbing deteriorated roadways. For the past 50 years or more, cold recycling, often called stabilization, has been practiced with equipment including rippers, scarifiers, and pulvimixers that have mixed stabilizing agents into the underlying materials.

Today's methods of cold-in-place recycling (CIR) are far more sophisticated, and involve a train of machines that pulverize the asphalt, mix it with emulsion and a bit of water, and spread the reclaimed material down for compaction. CIR is sometimes called partial depth recycling, because some of the pavement is left intact. The cutter does not penetrate through the pavement into the base; that is a different process called full-depth reclamation.

CIR is slowly gaining popularity, said Mike Polak, a partner with cold recycling contractor E.J. Breneman LP, Reading, Pa. Polak is a past president of the Asphalt Recycling and Reclaiming Association. Last year he performed 25 different CIR projects in four states—most were in Pennsylvania while the others were in Maryland, Delaware, and Florida. In size, the projects ranged from 5000 square yards to 30,000 square yards.

“I would say, confidently, that cold-in-place recycling has grown at about 10% a year for the past five or six years,” said Polak. “In the state of Pennsylvania there are now three companies that do CIR; when we started back in 1984, we were one of two companies.”

Polak said CIR can slash between 20% and 50% from the cost of conventional removal and replacement of pavement materials. The process involves no trucking of aggregates or hot mix. “The best aggregates we have are in place already; why not reuse them,” said Polak.

“The process is growing, but you've got to educate people, and it's not an easy sell,” said Polak. He reports three satisfied customers in Maryland:

  • Harford County has been doing CIR for 10 years
  • Frederick County started CIR four years ago
  • Howard County did its first CIR project in 1998.
  • All three Maryland counties are very happy with cold-in-place recycling,” said Polak.