This first article in a two-part series on recycler/stabilizers discusses their value in asphalt applications. A subsequent article will take a look at their growing use in soil stabilization, as well as discuss selection criteria for matching these machines to the application.
Reclaimer/stabilizers provide a solution to a nagging infrastructure problem. Many asphalt roads are deteriorating, and the "farm-to-market" roads are carrying loads they were never designed to handle.
Many times, road repair will be done by milling off the top layer of asphalt and replacing it with an overlay. While this can be a quick fix in certain circumstances, it does nothing to correct structural problems.
This is where reclaimer/stabilizers come in. Reclaimer/stabilizers allow the use of Full Depth Reclamation (FDR) to upgrade these surfaces. The FDR process solves many of the problems associated with reconstruction. "With a full-blown reconstruction, there can be disruption to the municipal environment and the traffic flow," says Dave Dennison, product manager - soil products, BOMAG Americas. "With reclamation, you can get in and out of there faster."
"FDR is a great tool because you can take that old road, pulverize it, blend it with cement or some other additive, widen it and you have a pretty good template to start with," says Chuck Valentine, owner of Vancouver, WA-based Valentine Resurfacing, which has been tackling FDR projects for close to 15 years. "Every instance where a county or city uses the FDR process, I can't think of one situation where they haven't had their eyes opened and said this is a really great tool."
One reason is it provides a more permanent solution to road repairs. "FDR is going to take a little more time [than mill and fill], but it is going to fix a lot more problems," says Tom Johnson, Mid-State Reclamation and Trucking, Lakeville, MN. "When you do a mill and fill, you have done nothing to take the pothole out, get rid of the crack or homogenize the mix."
John Edwards, Site-Prep of NC, Monroe, NC, adds, "If you are getting to the point where you see roads where more than 15% requires patching, it is not economically feasible to go out and patch it and overlay it. You are going to be back within a year to patch adjoining sections."
On average, a mill and fill job may last three to five years, he notes, while FDR can increase the lifespan to 15 to 20 years. "When you look at it with a life-cycle analysis, it just makes sense to do FDR," he says.
Lower material costs
Mid-State Reclamation and Trucking has been involved in FDR since 1992. "I was the first contractor in Minnesota to put a machine into service for FDR," says Johnson. "Now I have six machines and there are probably 20 machines in the state.
"FDR is one of the easiest ways to widen a road," he continues. "If the road was 22 ft. and there is room for the shoulders, we can just incorporate the shoulders and all of the mix together and put back a 24-ft. lane."
Compare this to full reconstruction, which is an expensive and time-consuming process. "We used to build the roads from the bottom up. But we don't have that kind of money, so we have to figure out how to do it from the top down," says Johnson.
By recycling the material already in place, FDR offers many economic and environmental benefits. "RAP, along with all other aggregate, has gotten to be an extremely expensive commodity," says Edwards. "Coupled with liquid asphalt prices that are bouncing between $400 and $500 a ton right now, there has never been a better time to promote FDR."
Greta Wilt, Ray Hensley Inc., Springfield, OH, agrees, noting, "I see a better market for FDR as fuel and raw material prices keep increasing." Her company started doing FDR in the early '90s. "When you use FDR, you reuse everything that you have ever put on that road. The asphalt is ground up and reused in place. You are saving landfill cost and virgin aggregate cost."
Site-Prep of NC performs between 15 to 25 lane miles of FDR work per year. "We are [taking] the base and the RAP from the asphalt, strengthening the base and a lot of times using a chemical stabilizer — whether it is cement, lime or emulsion — to bind it all together to reconstruct a road," Edwards explains. "That is why it is so inexpensive relative to its alternatives.
"By stabilizing that base, you get a new structure," he continues. "It is not just replacing what was there; it is putting a new base in that can support higher traffic loads. You basically get a brand new road without having to do full reconstruction."
Right for the times?
Contrary to what you might think, FDR is not cost prohibitive. The investment in a reclaimer/stabilizer has the potential to pay for itself quickly.
"From a contractor's standpoint, FDR is not a big capital outlay to get into and I think the process is going to continue to grow," says Valentine. "There are opportunities for guys to get into this business.
"I am just seeing recycling in general really coming more to the forefront than it has in the past," he says. "It has really played into this whole realization that we have to conserve, we have to recycle, we have to be eco-friendly. At least in the Western states where we bid work, the process is growing pretty rapidly."
He adds, "Aggregate prices and availability and oil prices really tip the scales from a cost standpoint where you can see some pretty substantial savings in some of these recycling processes."
Peter Martin, vice president - equipment, Brown & Brown Inc., Salina, KS, agrees. "I would think in this type of economy that reclamation would be on the upswing just because you spread those dollars over more miles and use what you have," he states. "One thing I would say positive about reclamation is you leave everything where it is. You don't haul it off and haul it back. There is a real savings there."
"You have one machine burning 25 gph in fuel," Johnson points out. This is much cheaper than the equipment needed to completely remove the road and haul it away. "Go calculate out 10 trucks, another machine, plus everything else."
The trucking costs alone add up quickly. "I understand that it now costs about $.72 to $.85 a mile just for fuel to run a truck," says Martin. "Plus, it is not just the fuel. You have the labor, the tires and the oil. You save a lot by not moving that material around."
FDR has been around for well over 20 years, so the opportunities really depend on your region. But according to Edwards, "We are still at the tip of the iceberg as far as the market potential. A lot of these DOTs, especially in North and South Carolina... have just thousands of miles of secondary roads."
Yet, despite the potential cost savings, not all DOTs are ready to jump on the FDR bandwagon.
"It is beneficial for a contractor to add a reclaimer/stabilizer when there is a slow-down in the asphalt paving business and increased interest in the recycling/stabilizing area," says Tim Kowalski, recycling project manager, Wirtgen America. "But it is more than just buying a machine. There is a lot of educating of people that needs to be done before it is just accepted.
"Showing people that this process will be able to save them money and build better roads in the long run doesn't just happen overnight," he continues. "With recycling, you can show your customers how they can stretch their dollar to go a little further, which opens up the ability to do more projects."
Clearing the Confusion
There is often confusion between Full Depth Reclamation (FDR) and Cold In-Place Recycling (CIPR). People will use the terms interchangeably, but there is a significant difference.
"These two techniques are strictly dependent upon the depth of material to be recycled," explains John Irvine, vice president of sales and marketing for Roadtec. "Up to 6 in. is usually termed 'partial-depth' recycling and is best accomplished with a milling machine and grade controls to accurately control the depth of the material being processed. Beyond 6 in. is typically reserved for reclaimer/stabilizers and is usually referred to as FDR. This can go up to 20 in."
"FDR consists of going below the asphalt layer into the base material and combining this material back together using foamed asphalt, emulsion, cement, fly ash or [combinations of these materials]," elaborates Tim Kowalski, Wirtgen America. The process actually allows roads to be re-engineered to meet current and future traffic requirements.
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."