Smooth moves for asphalt pavers

The asphalt paver industry is changing the look of the paving train to meet new demands on the road

Asphalt Article December 28, 2000
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Something has come between the asphalt truck and the paver. It’s called a material transfer vehicle (MTV), and it’s leading the move towards a smoother surface state inspectors and the motoring public are demanding these days.

The MTV sits in the middle of the paving process, right behind the truck and in front of the paver. In the past, the truck and paver worked side-by-side to get the job done, but every surge or truck change usually resulted in a bump in the road. The MTV, which pulls material from the truck and distributes it to the paver, acts as the buffer. Some come with a certain amount of surge capacity, which keeps the paver moving if the next round of trucks is slow in getting to the job site.

“You’re going to see tremendous growth in the transfer material market, everything from shuttle buggies, to mobile conveyors, to pickup materials,” said David Salzmann, marketing manager for Pro-Pav. “Non-contact paving is what everybody is aiming at. When (state inspectors) come down the road with a profilograph and they start measuring deviations, you’ll see one every time you change trucks. (MTVs) keep the trucks out of contact with the paver.”

Incentive paving is starting to catch fire. More states are moving away from method specifications, where contractors are told what kind of equipment is to be used on the job to reach an end result, to performance specifications, which award or penalize based on the quality of work that is done.

“There’s going to be a continued drive to give the machines the ability to pave smoother,” Caterpillar product manager Bob Ringwelski said. “The pressure is coming from the fact that now there is a bonus involved in it, and a lot of contractors count on the bonus for profit.”

MTV technology isn’t exactly new to Roadtec. According to Jeff Richmond, vice president of sales and marketing, the company “pioneered the move 10 years ago.”

The industry also is hooked on

sonics, and along with that comes a heavier dependency on electronics. Pavers now come with sonic automation, or sensors, to monitor grade and slope controls, eliminating the use of a physical part coming in contact with the pavement. Assisting the sensor techonology are microprocessors, which carry the computer program needed to conduct all the measuring and adjusting.

All the hype comes from a paver market which is booming, thanks to the Transportation Equity Act of the 21st Century.

“I would have to agree with my competitors when I say it’s the strongest market we’ve seen in a long, long time,” said Richmond.

Large in size, large in number

And there are a lot of competitors who have a say in the manufacturing of big and mid-sized pavers, including Roadtec, Caterpillar, Blaw-Knox, Pro-Pav, Propaver, Cedarapids, Dynapac and Midland.

Blaw-Knox

Blaw-Knox, manufactured by Ingersoll-Rand, Mattoon, Ill., hits the road with two new pavers: the wheel-mounted PF-2181 and track-mounted PF-4410.

The PF-2181 is an 8-ft asphalt paver-finisher with a maximum paving width capability of 21 ft. Powered by a Cummins 6BT 5.9 turbo-charged diesel engine that generates 145 hp at 2,100 rpm, the model is equipped with a two-speed hydrostatic direct traction drive system which eliminates 70%of mechanical drive-train componentry and offers paving speeds up to 260 ft per minute.

Paving widths of up to 25 ft can be achieved with the PF-4410, which also comes with a Cummins 6BT 5.9 turbo-charged diesel engine and hydrostatic direct traction drive. Screed choices include both fixed width and power extendible 8-ft units.

Caterpillar

Laying track for Caterpillar is a fleet which includes the AP-1055B, AP-650B and the AP-1000B.

The AP-650B is the new kid in the company’s 8-ft asphalt paver class. The model adds a track paver to the Caterpillar line, and is driven by a Cat 3054TA turbo-charged, after-cooled diesel engine that kicks out 121 hp. Maximum pave speed is 220 ft per minute. The key to what the company calls a “smoother ride” is the triple-roller rear bogey, which combines three sets of wheels into one bogey that evenly distributes the weight of the machine and the screed across the length of each track. Outboard feeder drives allow for a narrower center chain cover, resulting in better material flow to the augers.

Cat’s Mobil-trac undercarriage highlights the AP-1055 paver. The Mobil-trac system combines the traction and flotation benefits of a track suspension with the mobility and ride quality of a rubber tire paver. The machine can reach paving speeds of up to 200 ft per minute and travel speeds of up to 10 mph.

The control system of the AP-1000B’s conveyor and auger drive eliminates feeder gates to adjust material volume. The conveyor-to-auger speed ratio can be adjusted to provide exact volumes of material, resulting in slower running feeders that operate full of asphalt. The system also accurately maintains mix levels in the auger chamber at all screed widths. Containing a Cat 3116TA turbo-charged, after-cooled diesel engine that generates 174 hp, the paver is driven by a hydrostatic propel system with four speed ranges.

A deceleration pedal, hydraulically adjustable augers and a speed control system are features available on all three models. The decel pedal allows the operator to control speed with a foot pedal, leaving both hands free to steer and control other functions, while the speed control system allows consistent speed to be maintained throughout the job.

Cedarapids

Cedarapids latest idea is the Smartrac System. Available on the company’s Grayhound Rubber Track Pavers, the system is friction driven and incorporates the company’s patented self-adjusting track tensioning system, three-point suspension, frame raise system, oscillating bogie wheel assemblies and a wider stance.

The self-adjusting track tensioning system maintains proper track tension at all times, and because it’s hydraulically operated and self-charging there is no need for manual adjustment.

Oscillating, rubber-coated bogie wheel assemblies are pivot mounted on a heavy-duty frame, and in conjunction with the three-point suspension maintain maximum track contact for a smoother operator ride and a higher quality mat.

The three-point suspension system isolates track movement from the rest of the paver, resulting in a smoother mat, more uniform track loading, improved tractive effort and extended track component life, according to the company.

The frame raise system gives the pavers ability to fine tune the head of the hot-mix material in front of the screed by raising or lowering the spreading augers.

A wide stance permits the pavers to straddle any hot-mix left behind the pickup machine during windrowing, and the machines can reach travel speeds of up to 10 mph.

Dynapac

The top duo for Dynapac, manufactured by Svedala Industries Inc., Schertz, Texas, is the F 30C (tracked paver) and F 30 4W (wheeled paver). Both are equipped with a Cummins 6-cylinder turbo diesel engine with 196 hp. A telescopic and hydraulically extendible screed and horizontal tube are designed for added rigidity and a uniform, tight texture, and the hopper can carry up to 25 tons of storage capacity. The conveyors have a lay down capacity of 2,600 tons per hour, are driven with proportional speed control and feature two variable displacement piston pumps which are controlled by limit switches or proportional sonic sensors. The machines also come with two separate and independent hydraulically driven augers with infinitely variable speed control.

Gilcrest

The Propaver 814 MPC, a product of Gilcrest Equipment Co., Holden, Mo., features a 76-hp diesel engine, an 8 1/2-ton hopper capacity, extendible and reversible augers in the screed extensions, load sensing hydraulics, a planetary-driven track drive, paving widths from 4 to 7 ft and 8 to 14 ft and travel speeds of up to 350 ft per minute.

Global Asphalt

An all-wheel drive asphalt paver is the big attraction for Global Asphalt Product Inc.’s Pro-Pav line. Claiming it’s an “industry first,” the 1110W is designed to offer a significant increase in tractive effort while maintaining higher road speeds. The system is designed such that power is supplied to each of the four front bogie wheels independently, which means if one of the front wheels loses traction, the remaining three continue to drive with maximum torque.

The Pro-Pav Series Swiftrac 1110RT and Pro-Pav Series 780W also are new to the company. The Pro-Pav Series Swiftrac 1110RT showcases a Cummins 6BTA 5.9 turbo-charged, after-cooled diesel engine which has been increased to 200 hp. The 1110RT has a top speed of 13 mph, and the feeder system is fully proportioned and comes standard with ultrasonic material level sensors. The augers are hydraulically adjustable from 5 to 10 ft above the ground.

A unique portal axle drive is the backbone of the 780W’s propulsion system. The portal axle provides differential steering and the option of differential lock or modulated steer assist pedals for better traction and handling.

Midland

Midland is going with the “wider is better” approach after announcing a self-propelled 10-ft road widener at ConExpo/ConAgg ’99.

The SP-10 is capable of laying up to 450 tons of material per hour at a paving speed of up to 150 ft per minute. The machine will spread from 12 in. below to 12 in. above existing pavement, and is powered by a 125-hp, turbo-charged John Deere 4045T diesel engine.

Roadtec

Roadtec is letting gravity do the work in its redesigned SP-100B Stealth asphalt paver. It is a gravity-fed machine, meaning it has a hopper which is designed for the materials to feed by way of gravity direct to the augers in the paver. It comes equipped with a 10-ft standard vibratory screed. Other design changes include increased transport speed and engine horsepower.

Mighty mites

What’s in store for asphalt pavers down the road? Because there is a higher demand on the resurfacing of roads, some predict a switch to smaller, more maneuverable equipment.

“People are going to want a smaller paver to make it easier to maneuver, but I think they’re going to want a small paver that can do a big job,” said Cat’s Ringwelski.

If that’s the case, companies like Gehl, Puckett and Layton are heading in the right direction.

Gehl

Taking a step up from its 4-ton 1400 Series, Gehl now offers a 6-ton 1600 Series Power Box asphalt pavers. Armed with a 6-ton capacity hopper, Power Box pavers offer paving widths from 4 to 12 ft and adjustable paving depths up to 6 in.

Puckett

Puckett’s 500 Series asphalt pavers come with dual hopper cylinders for higher lift and stability. The 540 and 550 are powered by a 28-hp diesel engine and carry a maximum paving width of 12 ft, while the 560 operates with a 37-hp engine and has a maximum paving width of 13 ft.

Layton

Trying to push a line of tow pavers is Layton, which produces a D-550 Super Paver.

Charged by two propane-powered engines, the machine can produce a paving width of 12 ft, paving depth of 2 in. and can cover 100 ft per minute.

Layton also produces a H-500B and F-525 paver. The H-500B has screed extensions from 8 to 12 ft that can be adjusted while the machine is stopped or in motion, a hydraulically controlled shut-off gate to stop the flow of material from the hopper and a screed lift for maneuverability.

The F-525 can pave to a width of 12 ft and depth of 2 in. at a rate of 100 feet per minute.

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