Concrete Myth Busters

Along with concrete and asphalt pavement, today’s road builders and aggregates recyclers are crushing old stereotypes about the process. Many of the traditional rules of thumb about crusher use have gone by the wayside. These include everything from the tonnage required to make a profit, to the physical plant to a refreshing change in many highway engineers’ views of recycled material.

"Today, we’ll look at projects down to 5,000 or 6,000 tons—especially if it is a back-to-the-highway job," says Mark Wachal, partner and co-founder of Recycled Materials Co., Arvada, Colo. The company has been in business since 1988 and has 30 million tons of crushing history behind it.

"In the early years, we used to joke about ‘moving the carnival.’ There were 20 loads to get all the pieces to a job site," Wachal recalls. Crusher plants were large, involved operations. A job had to offer at least 30,000 tons of material to make it worth their while—both from the dead time and the cost to move the equipment to the job site.

"Since then, we’ve moved to track-mounted, highly portable crushers and screens," Wachal says. Now it is a simple six-load fleet, a mere 30 percent of what it used to be.

The result, says Leonard Cherry, owner of the Cherry Companies, Houston, is that companies can service more, smaller jobs than ever before. His operation includes Cherry Demolition, Cherry Crushed Concrete and other C&D divisions, making it Texas’s largest C&D crusher.

"Our cost of mobilization has decreased. So we can move on smaller projects," he explains. "The great thing about it is the amount of material recycled goes up."

"Crushers are more mobile now," agrees Jim Dykes, president of Dykes Paving, Norcross, Ga. "You can go out and crush material in a pile. You can walk them down the highway, crushing and putting the material back in place. Before, you had to load everything on a truck and move it off site."

Time requirements have also changed. No longer does a contractor need to have five, 10 or 30 days of work to justify setting up a crusher. "Years ago, that was true. But today you can drive them on and off a low-bed in 15 minutes and be crushing pavement right away," says Tom Barry owner of Barry Equipment, Webster, Mass., an Extec/Fintec dealer.

"Now, it is more job specific," Barry continues. "With transportation costs what they are today, it’s common for contractors to move in a crusher even if there are only three days worth of work."

Wachal agrees. "Size is not quite as critical as it once was," he says. This change, for Recycled Materials, started in the mid-90s and really came to the forefront after 2000.

"And don’t tell me about the cost of diesel," Dykes says. But that is only part of the cost savings with on-site processing. "There is big cost effectiveness to leaving the material on site as opposed to hauling it off. Off site typically requires paying a tipping fee. Then there’s the cost of the crushing, then sending a truck back at a different time to pick up the material."

Dykes says he sees the highway C&D market as a segment, unlike building C&D, that is open to growth and innovation in equipment. "I think you’ll see a lot more processing equipment that can handle roadways in different ways," he says.

Cherry says that they have invested in different sizes of processing equipment to meet the requirements of different size jobs. "If it’s a 50-ton job, we mobilize one type of equipment. If we’re looking at a 1,000-ton project, we send out different equipment." When looking at a bid, he visualizes three tiers of portable equipment, sizing the units to the jobs.

"A second element you have to throw in is the cost of disposal—both trucking and fees," Wachal notes.

At larger highway repaving projects, it is increasingly common to bring a crusher on site to accomplish one of two things: to crush material before loading it into densely-packed trucks so that far fewer trucks need to leave the site (versus numerous trucks with a few loosely-loaded slabs); and to crush material so that it can be re-used on site either as base course, or perhaps some to be mixed in as aggregate into new paving material.

However, it often is profitable to make a short haul to a single location by combining several short hauls.

"Today, we can erect and operate in much tighter confines," Wachal says. It is not uncommon for them to set up operations in the median of a highway or in one loop of an off-ramp cloverleaf.

Since today’s equipment has fewer conveyors and fewer components, it can fit into a more compact area.

Years ago some states—Idaho, Utah and Missouri among them—were reluctant to consider recycled material in new pavement. Highway engineers simply did not want to entertain the idea of recycled material. Legitimate concerns about contaminated aggregate were used to submarine the whole concept. That has changed.

"It’s the fat wife syndrome…you like what you’ve got and you can’t change it," says Cherry, with a chuckle (and noted that it does not apply to his wife of 30-plus years).

Federal regulations have helped change that mindset. Federal Highway Administration (FHWA) funding for highway jobs are backed by a strong, accepted recycling policy. FHWA encourages use of recycled materials. Texas was one of the leading states in going to recycled materials—in fact, TxDOT’s specifications were one of the models for the FHWA program. Despite that, even in Texas there still are pockets of resistance.

"That does not make Texas bulletproof," Cherry says. "The attitude differs from (highway) district to district."

Wachal also credits some of the resistance of past years to the engineering mindset of doing again what they lived in the past.

"The new generation of engineers is more accepting and excited about recycling. But 15 years ago, it was seen as a waste product," Wachal says. "Some of those guys have the engineering mentality of reaching second base without taking their foot off of first base. They never want to take a risk."

Almost everyone in the industry sees that ultra-conservative attitude changing. "They are more cognizant of accepting crusher material," Dykes says. "Everything these days is going green and nobody at the Department of Transportation wants to go backward. There is pressure on them to use crushed stone."

Cherry says the resistance from engineers is less than ever before. "Have we eradicated it?" he asks. "No, but it is less than before and decreasing."

Cherry’s goal is to recycle 100 percent of the concrete, steel or asphalt his crews find on any job. People—whether highway engineers or average citizens—like the whole idea of recycling, he notes.

"We’ve done a lot of highway recycling based on value engineering proposals," Wachal says. "We design, discuss and defend the project based on sound engineering."

Today, when an engineer resists the idea of using recycled material it usually is because it is something they have not really thought about deeply. Most crusher operators find it straightforward to educate the engineer about the concept, adding in that the funding for many projects is tied to FHWA money. Wachal says they never try to embarrass or force an engineer to accept crushing. But they have the figures to back up its worth.

Dykes says the pressures are on the general contractors to talk about recycling and to assure quality control. He says they have "trained" most of their customers to accept concrete aggregate as a base.

"Years ago, we had to beg customers to try it. Now we’ve trained most of our customers and they actually specify a recycled concrete aggregate base. Many say it holds together better than crushed stone."

That brings up another ticklish issue: the resistance from primary aggregate producers to the use of recycled base. Dykes came up with a unique way to skirt the issue—they set up a joint venture with quarrying giant Vulcan Materials years ago. "They quit lambasting us," he says. While the joint venture has since been absolved, Dykes continues to purchase a lot of aggregate from them and relative peace has descended on both sides of the issue.

Dust control is an absolute necessity for a successful crushing operation, crushers agree. (For more information on one company’s approach to dust control, see "Concrete Results,".) So is the integrity of the material.

Even though recycling C&D material is gaining acceptance in the engineering community, that does not mean that other branches of government are as welcoming. Permitting is increasingly challenging in the industry.

The requirements for permits vary from location to location. Dykes says that most jobs in Georgia do not require a permit. "You just set (the crusher) up and go to work." One exception is a state-wide air quality permit that should be obtained by the contractor.

"Permit requirements are more restrictive than before," Cherry says. "The pressure comes from various sources." Proximity to homes and businesses, noise from trucks, and other factors play into the mix.

Speaking of mixes, another key on-the-job factor is the mix of material recycled.

"You have to ensure that it is all concrete…that it is not clays or expanded shales. You are dealing with high-quality, ground limestone," Wachal says.

To end up with a good crushed product, the place to start with is a careful operator, he adds. "A careful operator will be careful not to pick up the underlying clay or get careless and allow rebar or metals out of the screening process.

Dykes recycles all of the metals. "The problem with recycling large rebar is you get very little money for it," Dykes says. Most purchasers want their steel cut into three-foot sections and then will pay in the vicinity of $250-$300 per ton for it.

"There is not much more you can do to liberate steel from the mix," Dykes notes. There is a cost to cutting or shearing it. They’ve tried all sorts of things—cutters, shears, the jaws-of-life-style of equipment. He says the best they have seen are the units with carbide wheels on a chain saw-like tool.

Cherry says there is another negative factor affecting the business. It is a factor that he says some in the industry still try to sweep under the rug: the slipshod operator.

"We are a young industry in some aspects," Cherry says. "Some people in the business don’t do the job as well as they could.

"This business needs to do a culling process," he continues. Otherwise, he fears a climate of ever-increasing restrictive permitting and monitoring requirements.

However, Cherry is optimistic. "Recycling C&D is here to stay. Green is not a trend or a fad. It’s mainstream."

As the cost of fuel increases, the cost savings and returns from recycling highway C&D materials becomes more competitive. That makes the industry a true growth industry—for the companies that do it right.

"Never produce a product that puts you in a position you have to apologize for," Wachal reminds his crews, emphasizing the need for quality control throughout the process.

The author is a contributing editor to Construction & Demolition Recycling and can be contacted by e-mail at curt@curtharler.com.