When you've been paving roads and parking lots since 1959, you know what you want in a roller. Paving contractor Black Diamond in Oak Creek, WI, has been doing just that and today operates 14 rollers that range in drum size from 30 to 84 inches wide. Five of the company's rollers fall in the smaller 3-ton category and are employed primarily for parking lots and driveways.
What does this contractor look for in its rollers? "Sure, price is important in any buying decision, but you also get what you pay for," says shop manager Ted Schulz, who has been with Black Diamond for 23 years. "We probably put 1,000 hours a year on our rollers. We look for a good, pressurized watering system that allows our operators to use the least amount of water possible. Being able to shut off one of the drums on our double-drum vibratory rollers gives us added versatility, and I prefer air-cooled diesel engines over gas. Diesel power is more reliable and air-cooled engines take one step, checking the radiator, out of the maintenance equation."
Black Diamond employs upwards of 50 people who operate six paving and grading crews. Like most paving contractors, the company looks for ways to increase productivity, and to keep pavers moving all day long. "Reliability continues to be an important factor in all our purchase decisions," explains Schulz. "The manufacturer has to stand behind its product, provide field support, and have excellent parts availability. Any piece of equipment, no matter how well it is made, will eventually break down, and when a roller shuts down, so do the pavers and the trucks hauling the mix.
"Being productive also requires that machines are easy to maintain. The easier a machine is to maintain, the better it will be maintained."
Black Diamond is typical of mid-size paving contractors who operate rollers of all sizes, including smaller compact units. But small rollers do not imply a small market, according to Tim Springer, mideast regional manager for Texas-based Dynapac. The smaller roller market accounts for somewhere between 25% and 35% of all roller sales, he notes.
Dynapac offers nine asphalt rollers in the 1¾ to 4¼ ton category. Two, the CC 102 and CC 122, come standard with dual controls to make roller operation easy for both left-and right-handed operators, and a slide seat moves side to side and forward and back to enhance operator visibility. The company also offers a patented isolation system that reduces vibration with four shock mounts. "Vibration is more of an issue on larger rollers," Springer says, "but we have the mounting system on our smaller rollers, as well."
Other features include timers on the water sprinkler that give operators a choice of three watering settings so "they can apply more water to the drums on hot days and reduce water output on cooler days," and a sprinkler bar that is integrated into the top scraper on the front and rear drums. "The sprinkler has self-draining nozzles to prevent lines from freezing on cold evenings," he says. "All four drum scrapers are spring-loaded to reduce maintenance time and help spread the water."
Springer says a contractor can pay anywhere from $7,000 to $30,000 for small asphalt rollers.
Productivity, he adds, will continue to be a big concern for all contractors, as will accountability. "It's not just how fast you can put down the pavement, but how well you put it down, too," he says. "New technology, the positive influence Europe has had on our paving market, and higher grade mixes have all contributed to customers having higher expectations from their paving contractors."
Ingersoll-Rand compaction marketing manager Dale Starry agrees.
"One of the most dramatic ongoing trends in the market is the makeup of mixes. In the near future there will be little if any conventional hot mix available. The new mixes require more compaction and a different way of handling the material, hauling mix in insulated trucks, for example. All paving contractors, not just those that pave highways, will need vibratory rollers, and every contractor, because of the higher cost of the mix, will be more concerned about waste." Echoing Springer, Starry adds that contractors will be required to pay more attention to quality control as customers specify how compacted and smooth they want a parking lot to be. Even homeowners will start to require (or ask for) warranties on their drives.
Mixing it up
The competitive nature of the marketplace and the emphasis on quality puts the average contractor between the proverbial rock and hard spot: to do the best job he can do and still be competitive on price. This places even more significance on equipment and the all-important buying decision.
"There are two extremes when it comes to smaller paving contractors," Starry says. "At one extreme are those contractors who spend little time comparing roller features and benefits and instead look only for equipment that will fit comfortably on their trailers. At the other extreme are those who absolutely match their roller size and speed to their pavers for optimum productivity. Most contractors fall somewhere in between, wanting to find a unit that matches their application, that will be productive, and will do a quality job for them."
He mentions a few features that are attractive to all productivity- and quality-conscious contractors. "Automatic controls that engage both vibration and the watering system are helpful, especially for less experienced contractors," he says. "Having the versatility to manually override the automatic systems allows operators to vibrate at slower roller speeds or apply less water as the application warrants." Ingersoll-Rand rollers, he adds, have a seat contact switch with a three-second delay. The feature will not "kill" the engine if an operator briefly stands or otherwise moves off the seat for a moment. Smaller Ingersoll-Rand rollers are powered by four-cylinder, liquid-cooled engines and feature a hydrostatic transmission with dual-drum drive, a sliding seat and control assembly, and standard ROPS with seat belt for safety.
In addition to looking at features and matching machine to the application they should also look into the future when buying a roller, Starry says. "Rollers are typically depreciated over a term of five to seven years, but they will operate efficiently for a much longer period of time. Contractors should buy units that will grow with their business."
Keep 'em rolling
"One of the most important features on any roller is reliability," says Vibromax manager of marketing and sales support Tom Meyer, reemphasizing that if a roller stops, so goes the paver, trucks, and job.
Vibromax has two models that fall within the 3-ton category ideal for average-sized parking lots, models 255 and 265.
"To help ensure reliability, all the hydraulic components, the engine, and the electrical system are very accessible on both of our units," says Meyer, who echoes Black Diamond's Schulz when he says, "Make the roller easy to maintain, and it will get maintained." The use of all-sealed bearings, he adds, helps to keep maintenance to a minimum.
"We try to make the roller as comfortable to operate as possible," Meyer says. "Our operator platform is located in the middle of the roller for good visibility in all directions. The location also means that operators are not sitting directly over a vibrating drum."
Having a compact and easy-to-maneuver roller is also important for smaller jobs, he adds. "Our model 265 features a 65-inch turning radius. You would not be rolling while turning this sharp, but operators still need to get around light posts and sharp curves. The unit is only 94 inches long, too."
Other features include a non-corrosive, pressurized watering system with 10 spray settings to adjust watering intervals and dual, retractable vulkolan scrapers on each drum.
Contractors know how important rollers are to the end product. As Starry points out, a mix will be comprised of between 20% to 25% air voids. A paver might remove 5% or slightly more of this empty space and the roller is left to remove the rest, short of a few percentage points. Over-rolling can damage the pavement and under-rolling or otherwise failing to do a uniform job can leave waves in the pavement.
Frequency, amplitude, and speed all come into play here. Contractors have to adjust their roller's ground speed to accommodate a frequency of 10 to 14 impacts per linear foot. The magnitude or amplitude of each impact, the effects of which Starry compares to how far a hammer travels to strike a nail, is fixed on most small rollers. With automatic systems gaining in popularity, operators can focus more closely on the job at hand: providing a uniform, high-quality end product.
As the above manufacturers point out, the small paving market is changing. Many of the smaller rollers will soon be equipped, if they aren't already, with features that rival their larger counterparts, thanks in large part to increasing competition, higher industry standards, and changing technology. But big rollers or small, the bottom line is the same: You need a piece of equipment that is versatile, productive, and reliable.
Based in Neenah, WI, Rod Dickens is a freelance writer specializing in the construction industry.