Recycling Yields Better Roads

Reclaimer/stabilizers actually can't be used for partial-depth reclamation. One reason is the teeth need to be cooled. "What cools them is going into the base material. So you have to go through that asphalt," explains Jim Holland Jr., product manager, Terex Roadbuilding. "The other reason you can't do it is these machines are mounted on rubber tires. They do not hold grade when they start bouncing."

Adding to the confusion is the fact that reclaimer/stabilizers and milling machines can often be found on the same jobsite, particularly when extremely thick pavement is involved.

American Road Reclaimers, a Sycamore, IL-based contractor, specializes in FDR, asphalt pulverization and soil stabilization. "We are using a Caterpillar RR250," says Joe Tyrrell. "There are times when we have gotten into as much as 12 to 13 in. of asphalt and have been able to successfully reclaim it. That is a rarity. When you are getting into that much depth, realistically, you need to look at milling a certain amount of that material off and recycling it through RAP."

In very thick material, Ray Hensley Inc., Springfield, OH, will mill a few inches off to restore the profile of the road, then reuse the reclaimed aggregate at the asphalt plant or as base somewhere else. "It still leaves us enough to blend into the underlying base," says Greta Wilt.

Brown & Brown Inc., Salina, KS, has been in business since 1946, but transitioned totally into CIPR and FDR in 1985. Many of the interstate projects it has worked on had up to 2 ft. of existing asphalt.

"We would have to mill several passes," recalls Peter Martin, vice president - equipment. "We have done lots of different applications where you have to mill some off and haul it to an asphalt plant site." The road would then be reclaimed using FDR. "You come back with the RAP along with the virgin mix and cover it all back up again."