Controls Keep Concrete Pavers Striving for Smoothness

Jan. 3, 2013

As the concrete paver market continues to struggle, manufacturers have been refining paver controls and features that can increase contractors’ adjustment speeds, keeping in mind the ultimate goal—pavement smoothness.

Demand for concrete pavers has been slow to rebound in the five years since the recession began. And slow may be a kind word.

As the concrete paver market continues to struggle, manufacturers have been refining paver controls and features that can increase contractors’ adjustment speeds, keeping in mind the ultimate goal—pavement smoothness.

Demand for concrete pavers has been slow to rebound in the five years since the recession began. And slow may be a kind word.

“My crystal ball is as foggy as the next guy’s, but I’ve never seen the economy with such lack of direction,” says Larry Eben, district manager for Terex Roadbuilding, and a 33-year industry veteran going back to the pre-Terex days with CMI/Bid-Well.

Cost of Concrete Paver Ownership

Size Class (lb.) Average Price Hourly Rate*
19,000-27,999 $149,450 $76.52
28,000-39,999 $211,657 $110.41
40,000-54,999 $271,977 $150.98
55,000-96,900 $423,685 $262.23
97,000 and more $560,059 $338.16

*Hourly rate represents the monthly ownership costs divided by 176, plus operating cost.
Unit prices used in this calculation: diesel fuel, $4.13 per gallon; mechanic’s wage at $50.76 per hour; and money costs at 2.0 percent.

“I still see the market as being unpredictable, and even soft in areas,” Eben says. “The highway bill that was passed last year was a two-year bill. The money’s going to be slightly reduced for 2013, and then it’s done and the industry is fighting for money again for highways.”

The fact that the federal bill contributes about half the money for projects and the states usually have to come up with rest adds to the problem, according to Eben. “Many of the states are financially strained; they’re just as challenged, if not in worse shape, than our federal government is,” he says. “While there’s always the chance for a surprise, I would say it’s difficult for a road building manager to be particularly optimistic on the market conditions right now.”

Kevin Klein, vice president of engineering, research and development at GOMACO, echoes Eben’s take, and adds an international component, as the company sells equipment in more than 90 countries.

“It’s still hard to be optimistic,” Klein says. “There haven’t been a lot of exciting things that will make it [the market] come back hard or fast and furious in the next year. Everything depends on not only what the government does here, but also in the other countries we sell in. It’s tough right now. No one can see far enough into the future to know what their market will be.”

The short-term nature of the highway bill is a problem in itself. First, it takes time for the effects to trickle down to contractors and equipment managers; second, the short time period breeds uncertainty of what’s next.

“We’d all like to have seen a five- to six-year bill, which gives DOTs assurances of what they’ll have to work with,” Klein says. “And, it’s difficult for a contractor to make the decision to buy a paver if he doesn’t know what funding there will be after one or two years. Has the bill helped our business? No, it has not.”

Buying in today's concrete market

A manager’s buying decision, of course, depends on overall prospects for business and what kind of paving he or she wants to do. Eben’s crystal ball is a little clearer on this subject.

He says the depressed marketplace indicates to him that counties, states, and the federal government will not be constructing much “new road.”

“You’re not going to see the new highway connectors or new loops,” Eben says. “The more adaptable your machine is to different types of work, the better off you’re going to be in the next two to five years.

“I think the rehab market is the one that’s going to be strongest in the coming years,” Eben says. “I’d have to ask what kind of work you’re going after. If there are several larger jobs on the horizon, you should be looking at a slipform paver. But make sure that you get one that’s adaptable to do variable width or variable segments easily. The rehab market is where more of those widths and segments are.”

Roller pavers are advantageous for work with changing widths and segments occurring in shorter stretches or confined spaces, according to Eben.

“For shorter or more complicated jobs, with variable widths, variable crowns and block outs, a slipform paver has a more difficult time handling and adapting to those different scenarios,” Eben says. “If you’re going to set up a paver once and just move along, a good crew can get a mile of that done in a day—so a long, straight part of an interstate, miles of flat nothing, that’s where slipforms shine. Do 20 straight miles of 2-percent crown and you’re done.”

In contrast, city jobs contain more challenges. “In the city, you’re going around curbs and turns are fairly sharp, and to get the super elevation done correctly, to get the crown coming in, to adjust to on- and off-ramps,  the slipforms don’t lend themselves to it as well,” Eben says. “They’ll work, but there are more areas left requiring hand finishing, and more setup time for the different configurations. A roller paver can do it faster; it’s sitting on the forms, isn’t as heavy, and it’s designed for quicker set up.

“Variable-width slipforms can do it to some degree, but when you have to stop, move the legs out, and reset all the time, it’s not a continuous flow.”

Terex Bid-Well offers two roller pavers designed for street and wider work, such as airports. The 5000 is a form-riding roller paver. The 6500 is available either on tracks or as a hard rubber-tired roller paver. Eben says that it does uses forms to contain the concrete, but it’s operated by a stringline for grade and elevation, and steering.

“Production-wise, it won’t do the big work as fast as a slipform paver, but the machine itself is 25 percent of the cost of a slipform,” Eben says.

“My advice to a contractor or manager would be to look forward,” GOMACO’s Klein says. “When you’re making a long-term purchase, position yourself with a paver and company that has advanced control systems, so you’re not falling behind in the technology, especially with the way things have been advancing in recent years. If you don’t buy a paver with a modern control system, you could put yourself behind the eight ball for advancements coming in the next five to 10 years,” Klein says.

“Position your company with equipment that has the ability to grow with your business.”

Concrete paver controls: old and new

In controls—one of the biggest keys to smoothness—there’s an “old school” versus “new school” technology choice for the market.

On one hand, GOMACO offers its G+ control and communication system that allows communication
between the paver’s valves and various sensors to enhance accuracy.

The sensored feedback is designed to provide tighter, faster and more accurate machine corrections. A CAN (controller area network) allows all of the components of the system to communicate with each other for precision setup and paving. At the heart of the  control system is GOMACO’s paving software. A “run” screen on the control panel illustrates the various aspects of the paver. It includes leg positioning, paving speed and percentage of drive, steering, travel information, grade information, deviation meters, and more.

All the components of a GOMACO paver can be interfaced through the G+ Connect system, which allows components to share machine resources for varying functions and pave the project with more ease and accuracy, the company says. For example, pulse pick-up sensors on the tracks of the paver can log the travel speed and distance the machine has moved. This odometer feature in the G+ controls can be shared between individual controllers for dowel bar inserters (IDBI), tie bar inserters (TBI), and power transition adjustors (PTA). These devices can use the speed and distance information to manage bar placements as well as transition distances for controlling where a super elevation is to start and stop on a project by controlling the PTA) crown devices. If the operator is going to use a 3D stringless control system or the GSI smoothness device, it will be “connected” through the G+ Connect system, as well.

G+ Connect features an entire library of sensor capabilities for controlling grade and steer with setup configurations for various project requirements, including paving with 3D stringless systems, laser control, sonic sensors, rotary sensors, and slope sensors and all of their setup requirements. Digital slope control is also available. Long and cross slope can be configured using high-resolution, dual-slope sensors.

“Controllers are becoming more sophisticated, but at the same time, easier to operate,” GOMACO’s Klein says. “Some customers out there don’t give enough consideration to having an advantage in controls.”

The old-school control system still in the market (called Hydramation by Terex) features a simple hydraulic design based on the old CMI hydra-sensor, featuring only two moving parts; one to control leg elevation and the other for steering. It uses a stringline for guidance, but is not affected by weather issues and doesn’t involve sensors that have to be removed from machines at night. “Yes, it uses a stringline and it’s a little more to set up, but when there’s an issue, it’s easier to diagnose the issue,” Terex’s Eben says. “It’s direct. There’s no connection losses, no dead band.”

Where concrete paver market is going

“In the area of new technology, we might go with electronic units if they become a little better, a little more user friendly,” Eben says. “In the future, I see GPS as being one of the biggest innovations on the market. One of these days, it’s going to get to the point where the GPS is so good that it’s going to get us accuracy to 1/8 of an inch in 10 feet. Today, if it is there, it’s not cost-effective for the application.”

Eben notes the progression that’s occurred in vehicle-based GPS units. “In your car, GPS systems now are better than earlier units, but they can still direct you to a wrong location. In the future, I see units going to a total station scenario as in how surveys are being done. We’ll tie in with the survey units, and paving will be so much easier and quicker.”

Klein also goes back to controls. “The future’s definitely going to involve continued advancements of controls, 3D machine controls, and telematics. We’re constantly looking at different ways to build pavers and improve the ride, and also to improve contractors’ ability to do different things.”