Added flexibility: Serving a variety of RAP mixes

An Ohio producer’s crusher proves capable of processing blacktop driveway tearouts of all sizes.

A Northeast Ohio asphalt producer is optimizing its use of reclaimed asphalt pavement (RAP) by processing it into consistent sizes, which are stockpiled and used as needed in commercial and Department of Transportation (DOT) mixes.

Tri-County Asphalt Materials Inc. serves the tri-county area around metropolitan Youngstown, Ohio, from a single batch plant adjacent to downtown Youngstown. Tri-County operates a 160,000-ton-per-year batch plant, from which it serves predominantly commercial customers with a variety of mixes on demand. About 80 percent of production is destined for private-sector use.

“Many of our customers pave driveways, residential developments and parking lots,” says Chuck Royer, plant manager. “We use this plant to make different mixes for our customers throughout the day. We run recycled asphalt 20 percent in base, and 15 percent surface courses, and otherwise use limestone from a quarry 20 miles south.”

Consistency of RAP feed is very important for mix production, Royer says.

“It’s very important, especially with state work,” he says. “We have to make sure what they’re getting in the mix is what’s called for in the mix design. In order for us to do Ohio DOT work, we have to make blended piles. Because the material comes from so many sources, this machine helps us process large amounts of RAP while still knowing the gradation and AC content via test samples. With this machine we have a lot more consistency than we did prior.”

Replacing rented equipment

Tri-County specifically uses a Mobirex MR 110 ZS EVO mobile impact crusher from Kleemann to process RAP. The single, compact machine replaces a rented crusher/screener and a small, in-line crusher mounted in the recycle system.

“We had problems with that small crusher,” Royer says. “It was wearing out and would plug up on us. We did a lot of maintenance on it.”

In addition to that small in-line RAP pugmill, Tri-County had the rented crusher/screener brought in to pre-crush RAP in advance of that in-line crusher.

“We’d rent a crusher/screener to process RAP, but we’d still have to run RAP through the in-line crusher,” Royer says. “That was an added cost.

Rick Vernal, president of Tri-County Asphalt Materials, says the MR 110 ZS saves his company on labor costs.

“Now, we have one guy feeding one piece of equipment, and the same guy pulling out a finished product,” Vernal says. “We’re only handling the product once. That compares to before, where we’d have two to three guys. They’d run RAP through the rented crusher, then through the screen, then through the crusher and back through a final screen. It was a lot more work.”

The new impactor gives more flexibility in feed sizes, Royer adds.

“Our new Kleemann lets us accept blacktop driveway tearouts of all sizes,” he says. “In the past, we were limited to 6-in.-diameter down. The in-line crusher was good only up to 20 tons per hour, and when material was damp it would tend to plug up.

“Rubber or crack sealants in the feed also would bind it up. We’d have to shut the recycle system down and would not be able to run RAP in mixes, meaning we’d have to run virgin, which would cost us money. In the meantime they’d spend two, three hours cleaning the crusher out and getting it back online. Now we can crush much larger size feed. It’s been working really well for us.”

Prescreen keeps out fines

Often, depending on how deep or fast a milling machine is operating, RAP feed will wind up as chunks, but also sometimes primarily as fines.

“That all is put into the crusher,” Royer says. “Most of the fines are screened out by the prescreen and into a pile, and whatever doesn’t make it through the prescreen is sent to the crusher to be processed. There’s no sense in sending all the fines through the crusher.

Also, instead of redundantly crushing everything that goes through the plant, Tri-County can screen off the fines ahead of the crusher.

“When we take grindings off the street, somewhere around half already is the size we need,” Vernal says. “To run that through the crusher when it’s already the right size is redundant and costs money. It makes sense to get it out of the way first, and then crush what’s left. We get a much more consistent quality of product with this crusher/prescreen.”

The final product out of the crusher is a minus 9/16-in. top size, down to dust, while the prescreen removes a little bit bigger material: a minus 3/4-in. down to dust.

“Its prescreen means we don’t have to send all the fines through the crusher,” Royer says. “Basically, we filter or screen out the fines beforehand. Once everything goes through the crusher and passes the screens, the RAP will be 9/16-in. down to dust. Eventually the 3/4-in. will be run through the plant and crushed to 9/16-minus size. We use the 9/16-in. in every mix we make.”

Tri-County’s only asphalt plant is located in a relatively small urban footprint adjacent to an interstate highway interchange, immediately southeast of downtown Youngstown.

“It’s always better to have more room, and we get that with the compact mobile crusher,” Royer says. “Integrating the crusher into our operation was relatively easy. It’s not a complicated machine. Kleemann personnel were with us for several days while we were starting up.”

The Mobirex MR 110 ZS falls under the control of the driver of the front-end loader, which charges the crusher.

“The driver operates the plant, but everybody in the plant has worked with it and is familiar with its operation and can run it,” Royer says.

The driver both feeds the plant with raw material and removes crushed RAP from one stockpile, as well as screenings from another stockpile (material from Kleemann’s prescreen).

Once the asphalt plant is up and running every day, that day’s operator will do all pre-checks to make sure the crusher is ready for operation. This includes oil checks, air filter inspection and greasing.

The Kleemann impactor works so fast that one day’s crushing can serve the batch plant for two days, Royer says.

“We crush it as we need it,” he says. “He’s crushing today, and then we’ll be good for a few days.”

Tri-County also has a Wirtgen W 1900 cold mill, but most of its RAP comes from other contractors.

“Our RAP stays fairly consistent, as most contractors place limestone pavements to Ohio DOT specs,” Royer says. “We have a lab that tests the material as it comes in from the field, determining liquid asphalt cement content. For Ohio DOT work, we also send RAP to them, and they test it as well.

Adds Vernal: “Our W 1900 cold mill works great for us. If you look at the Wirtgen line, they make the best grinder, the best paver, the best roller – we have a Hamm HD 70 roller – and so, far they make the best crusher/screener.”