N.H.’s Continental Finds ’Ozzies’ to Be Wizards at Compacting

Fri September 21, 2007 - Northeast Edition
CEG



A New Hampshire asphalt contractor has plunged into Hamm oscillation compaction with the acquisition of six HD O90V “Ozzie” compactors.

“We found that the HD O90V gives us an average 2 percent better compaction than other brands, all things being equal,” said Eddie Small, paving supervisor, Continental Paving Inc., Londonderry, N.H. “As a contractor that means we get paid faster, avoid penalties and achieve critical compaction sooner.”

This is especially true for airports, Small said.

“We have airport work where we have to meet strict density criteria,” he said. “That roller achieves it a lot easier than other rollers. We don’t have to struggle with pneumatic rollers and triple drums to get compaction. We get a lot better results with the oscillatory roller.”

The benefits of oscillation compaction sometimes requires some explanation to end users, but for Small, it was logical.

“It only made sense to me,” Small said. “If you can roll the stones so they fit better, as oscillation does, instead of pounding them down, like vibration, your compaction will be more efficient. I didn’t doubt it from the start.”

Using Ozzie All By Itself

“There are times when we will use the oscillatory roller by itself, without a vibratory roller. This might be on top, on thinner lifts, where we don’t need the pounding of the vibratory roller. We’ll run the oscillatory and it will give us a better ride, with easier compaction,” said Keith Dane, quality control supervisor, Continental Paving.

“In the state of New Hampshire we have to meet a ride spec and the oscillation makes it easier,” Small said. “If I can gain 90 percent of my compaction with just one roller, like the Ozzie does, I have a lot less to do behind it, like just smoothing the road out and putting all the pieces together.”

Continental frequently overlays bridge decks with hot mix asphalt, and the non-aggressive oscillation helps there.

“Because it doesn’t have the up-and-down vibration of conventional compaction, there is less stress put on the bridge,” Small said. “That could cause damage to a smaller bridge. Oscillation is a lot better for the bridge, and we still get compaction on the lift.”

“The New Hampshire DOT won’t let us use vibratory rollers on a bridge deck, but they will let us use oscillation,” Dane said.

What Is Oscillation Compaction?

Oscillation compaction works by “massaging” the hot mix asphalt (HMA) from side to side with a rocking action, rather than by forcing it downwards by an up-and-down motion. With oscillation compaction, the drum never leaves the mat.

Unlike traditional vibratory compactors that achieve compaction by “bouncing” the drum on the ground, Hamm’s unique oscillation technology ensures that the roller drums maintain constant contact with the ground for faster, more effective compaction.

In the oscillation drum, two eccentric masses turning in the same direction cause a movement around the drum axle. The movement changes its direction of effect during one turn so it generates an oscillating or rocking movement of the drum. Horizontal, rocking forces are transmitted from the drum into the pavement. The result is better compaction in fewer passes, with less vibration-related wear and tear on operators and surroundings.

Acquired 2116W Vögele Paver

This year, Continental complemented its six HD O90V rollers with an 8-ft. (2.4 m) 2116W asphalt paver from Vögele America Inc.

“We’re finding that it’s a small machine with a big-machine personality,” Small said. “You don’t have to use it only on small projects, you can use it all day. You can pave an 18-foot road with it, then pave a 30-foot road, without having to bring another paver out, which makes it a lot more versatile.”

Small took note of the 2116W’s tractive power.

“In Concord, New Hampshire, it was pushing loaded Flow-Boys up an 8 percent grade,” Small said. “That’s remarkable, because 8-foot machines either usually don’t weigh enough, or have enough power. Most inspectors who walk up to it have no clue about it’s power.”

In New England, Continental Paving is on a roll, so to speak. Continental Paving Inc. is a major player in New England road building.

It began in the 1970s as a family owned and operated trucking business that expanded into related work such as site development, utility installations and ultimately, paving. The firm was incorporated in 1981.

Continental Paving is vertically integrated and is in control of its own resources from raw materials, to plant, to field equipment. Its work force of more than 250 employees is engaged in portable aggregate crushing operations, pavement milling and reclaiming, asphalt production and sales out of two stationary and one portable asphalt plants, aggregate production and sales from its Litchfield Sand and Gravel operation, and a Continental Paving-owned and operated stone quarry and crushing facility.

This article was reprinted with permission from Wirtgen Technology.