The design of Caterpillar's newest 10-foot asphalt paver models, including the wheeled AP-1000D shown above, eliminates the need for feeder gates. That's because the left and right augers and the left and right feeders can be controlled independently of each other.
A recent addition to the Terex Roadbuilding product line, the CR662 model combines a material transfer vehicle with a highway-class asphalt paver, providing the paving train with a multi-purpose machine.
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If the current generation of construction equipment has one overwhelming differentiation, it is in the proliferation of multi-purpose machines. In many equipment types, the single-purpose unit has all but been eliminated as OEMs develop products built to work continually, from one task to another, each formerly performed by a different machine. Regardless, by their own unique designs and purposes, some equipment types may seem destined to steer clear of thistrend. They are what they are, and nothing more.
Well, if you're thinking full-sized asphalt pavers are just that, think again.
In rolling out its CR662RM model in 2006, Terex Roadbuilding combined a material transfer vehicle with a highway-class paver. Bill Rieken, paver applications specialist, says it could be the wave of the future, "certainly from versatility and utilization standpoints, and the fact that it can be moved like a paver. The CR662RM has the same ground pressure as what a track paver has, and yet performs all the things a transfer vehicle would."
As a paver in the Terex Cedarapids line, the CR662RM's outboard bearing drive is a new feature with market potential, said Rieken. "Instead of the center spreading auger drive, we have two outboard drives to eliminate the potential for centerline segregation."
The availability of a multi-purpose machine in the paving train may require a different train of thought for managers and users.
"In about half a day, it can be converted from a transfer vehicle to a paver, or vice-versa," said Rieken. "If they elect the option to be able to take both approaches, either as a paver or transfer vehicle, then they can optimize the equipment a lot more than what they can as a paver alone or a transfer vehicle alone.
"I'm sure some contractors may just purchase it for one application or the other," said Rieken, whose company offers 14 full-sized paver models. "But just knowing that they have the option, should they so choose, to make it a transfer vehicle instead of a paver, or vice-versa, that has to create a lot of interest."
A survey of OEMs by Construction Equipment indicated seven in the North American market currently offer full-sized asphalt pavers (those weighing more than 19,000 pounds).
In addition to established 8-foot and 10-foot rubber-tired and rubber-tracked models, Roadtec offers a new fifth model unique to the product line. The 10-foot SP-200 Spray Paver sprays tack and then applies hot mix asphalt seconds later, combining spraying and laydown for a "high-quality" mat with a strong bond between layers. A spray bar located just in front of the paver's auger distributes the liquid through computer-controlled, self-cleaning valves, arranged in sets of three for added capacity and faster paving. An onboard microprocessor controls the rate of flow.
Hot mix enters the SP-200's hopper from the chute of the Shuttle Buggy, the material transfer vehicle offered by Roadtec, an Astec Industries company. The Shuttle Buggy's ability to remix combined with the Spray Paver's strong bonding allows the laying of smooth pavement as thin as a half-inch.
Another OEM focused on allowing customers to do more with its pavers is Dynapac, as evidenced in the 2006 U.S. debut of "Kompact Asphalt Paving" on the test track of the National Center of Asphalt Technology at Alabama's Auburn University.
Allowing "hot-on-hot" monolithic pavement to be laid simultaneously in a single pass, the Dynapac F-300 C/S twin-paver consists of two hoppers: The upper hopper, holding the wearing course, has a capacity of 25 tons; the lower hopper, for the binder course material, holds 45 tons.
As demonstrated on the test track, the first of two screeds placed the binder course while compacting it to a density of up to 97 percent. The second screed placed the top course directly over the freshly placed binder and compacted it to a density of 92 percent. The screeds can be adjusted to reduce or increase compaction as required.
Following the demonstration, Dynapac vice president and general manager George Platt said the company is planning to bring the technology to market in the United States.
In the past 18 months, Ingersoll Rand has solidified its role as the most extensive provider of full-sized asphalt pavers, adding six models as part of a 19-model offering. In North America, all are marketed as Ingersoll Rand products, incorporating the former Blaw-Knox and ABG brands, the latter represented by the Titan product line.
The track-mounted Ingersoll Rand PF-6110 and wheel-mounted PF-6160 and PF-6170 models were introduced last fall, each incorporating an auger system now independent of the control system. Each of the two auger and conveyor drives use sonic sensors for more precise handling of material. Hopper capacity for the PF-6000 Series is 14.4 tons, giving each paver a practical production rate of 820 tph.
With hopper capacities ranging from 14.8 to 19.3 tons, Ingersoll Rand's new Titan 7820, 8820 and 9820 pavers feature Ingersoll Rand's Electronic Paver Management II (EPM II) control unit as a standard feature. The EPM II provides information on paver functions, operating conditions and machine diagnostics through an intuitive interface.
Similarly streamlined in terms of brand offerings is Caterpillar, which incorporates the former Barber-Greene and Bitelli technology into a five-model Caterpillar product line, highlighted by the newly updated AP-1000D and AP-1055D models.
With a hopper capacity of 12.2 metric tons, both the wheeled AP-1000D and tracked AP-1055D models feature "the most advanced material-handling system in the paving industry," reports Cat Paving's Terry Sharp. The ability to control each of the left and right augers and left and right feeders independently of one another eliminates the need for feeder gates.
Vogele America, a member of the German-based Wirtgen Group, offers five "lane-width" asphalt pavers, all U.S.-designed and built in Chambersburg, Pennsylvania. Depending on the size of the screed mounted, each of the third wheeled and two tracked models will pave 10-foot-wide sections.
Vogele America has uniquely mounted the drive motors on the outside ends of the torque hub, allowing any leaks in seals or hoses to be immediately visible. Another Vogele exclusive is the use of two hydraulic motors on the final drive of the 10-foot-class 2219T tracked model. All four shifts may be done hydraulically, permitting smoother and more efficient shifting, including shift-on-the-fly at any speed.
Renowned for smaller, commercial-sized asphalt pavers, LeeBoy moved into the full-sized paver market with the 25,000-pound 8816 model, offering owners the option of a conventional propane-heated Legend screed system or the new Legend Electric system. The electric system eliminates the flame, fuel or fumes, while offering consistent temperature control of the heating elements across the width of the screed plate and extensions.
Productivity is enhanced with the LeeBoy 8816's under-auger cutoff doors and independent control of hopper conveyor and material augers to control asphalt flow to the screed.
The future of mainline paving technology is not without frustrations, according to Terex Roadbuilding's Rieken.
"For highway applications, continuous paving is going to be more and more required," he said, "and how are you going to do that?
"Every state has a different spec," he explained. "Unfortunately, without intent, the states have kind of gotten in the way of technology, by trying to pick the technology that's out there that they're aware of, instead of keeping the door open for all of the technology."
The select manufacturers in the game will undoubtedly look to do more with the products they offer.
|Highway-Class Asphalt Pavers (by weight)|
|Model||Operating Wt. (lbs.)||Max. Paving Width (ft./in.)||Gross HP|
|Unless identified with asterisk, the model represented is a tracked paver only.|
|* Wheeled paver model only.|
|** A wheeled paver model, for which a comparable tracked model is available.|
|*** A wheeled paver, for which comparable steel- and rubber-tracked models are available.|
|Ingersoll Rand Titan 2820||20,925||13Œ1||81|
|Ingersoll Rand PF-161*||23,000||19Œ0||107|
|Ingersoll Rand Titan 3870*||26,674||16Œ3||99|
|Ingersoll Rand PF-2181**||27,650||21Œ0||158|
|Ingersoll Rand PF-3172||29,870||21Œ0||158|
|Ingersoll Rand PF-3200**||32,700||30Œ0||188|
|Dynapac F 121 6W*||33,069||23Œ7||158|
|Ingersoll Rand Titan 272-3*||35,015||24Œ7||152|
|Ingersoll Rand Titan 373-2 / 473-2**||36,559||26Œ3||152|
|Ingersoll Rand Titan 7820||35,720||32Œ10||231|
|Dynapac F 141 CR||38,139||19Œ6||173|
|Ingersoll Rand PF-6160***||40,352||26Œ0||205|
|Ingersoll Rand Titan 8820||42,115||42Œ8||247|
|Ingersoll Rand Titan 9820||52,038||52Œ6||371|
|Specifications ConstructionEquipment.com||Caterpillar www.cat.com|
|Dynapac www.dynapac.com||Ingersoll Rand road-development.irco.com|
|LeeBoy www.leeboy.com||Roadtec www.roadtec.com|
|Terex www.terexrb.com||Vogele www.vogeleamerica.com|