By Kim Berndtson
Whether new or used, equipment needs to be in top operating condition to be most productive. Take a ride-on vibratory compactor, for example. In order to produce a smooth mat with the desired density, all critical components need to be in good working order. Here are some more tips on roller maintenance.
Keep it serviced
Water system performance can deteriorate if you frequently use an unclean water source. "If you pull water from a ditch or lake or other unclean source, the system can be compromised as the filters will have to work that much harder to remove debris," says Dennison.
Regional differences can affect the water system, as well. If you operate in cold climates, drain the water spray system at the end of the day.
"Water in the spray system can freeze, which can damage the water pump and filter systems," says Sturos. "If the water spray system is inoperative, the compactor drums could pick up asphalt off the mat, resulting in a poor mat surface." Some manufacturers, including Caterpillar, offer an optional freeze protection system.
If you work in the South and equip your compactors with coco mats, make sure the mats are in place and contact the drum uniformly to keep it moist at all times. "When the drum is dry, hot asphalt can stick to it," says Marcum. "Each time the drum comes back around, it picks up even more. Then you have the added cost of stopping the machine, cleaning off the drum and repairing the damage to the asphalt where you picked up the material."
Operate rollers appropriately
Even how you secure the roller for transport can potentially affect component life. "If you over tighten the chains, you're drawing against the drum isolators and stretching and damaging them," says Marcum. "Become familiar with the machine and know when it's secure. There is no calibration or indicator, but an inexperienced driver can become too enthusiastic and tighten the chains too much."
When maintenance isn't enough
With manufacturers continuing to introduce new approaches to the compaction process, you may find that the benefits in terms of mat quality and productivity quickly offset any cost advantages of repairing an existing model.
For example, new Caterpillar vibratory rollers offer an enhanced propel control system design that produces a smoother mat by providing consistent and controlled acceleration and deceleration. "The sophisticated system can also sense when the operator requires a quick stop, providing safe stoppage when needed," says Sturos.
Hamm's oscillation technology - offered on select models - is also designed to generate a smoother surface by rocking the vibratory drum back and forth, rather than bouncing it up and down. "The drum never leaves the surface of the mat. It sends a vibratory effect, but it doesn't beat it into the material," Monical explains. "The direct affect is that you rearrange the particles and achieve the final density you need, but you don't bounce up and down. You don't ever break rock over or shatter the surface. You have an ultimately flat, smooth surface with no ridge lines or bumps."
From a productivity standpoint, after correlation on the test strip, an onboard stiffness reading enables you to evaluate the effectiveness of compaction in real time without the need to wait for additional outside tests.
BOMAG's Asphalt Manager (or "intelligent compaction") is designed to yield consistent compaction quality by taking mat readings, then automatically adjusting the drum energy into the material based on the results. "With Asphalt Manager, we're checking every square foot of the site. It's not random," says Dennison. "We also have the ability to document these results, which is becoming increasingly important for jobs that require documentation."
The ECO-Mode introduced on BOMAG's new high-frequency roller models early last year. The engine, engine controls, hydraulic system and vibratory system all work together to provide the engine speed best suited for the job.
"Practically speaking, if a roller operator is done with a certain section and stops and comes back to neutral, they don't need to be sitting there at 2,500 or 2,600 rpm. The machine will automatically idle down to a lower level to reduce fuel consumption and noise," explains Dennison. "Our goal is to get maximum compaction efficiency while using the lowest possible amount of fuel. It also increases component life expectancy by running them at lower rpm speeds."
More comfort = more productivity
Significant advancements have been made in the operator environment, as well, with features such as swivel/sliding seats, instrument panels and joysticks that move with the operator, enhanced visibility, etc. This all adds up to a more comfortable work station where operators can be more productive for longer periods of time.
"The operator station has improved to allow better control of the machine, as well as provide a safer machine to operate," says Marcum. "Specifically, moveable seats allow the operator to position himself on the side or edge of the machine for better visibility when rolling against curbing or other obstacles. With multiple seats or rotating seats, we can put the operator on the side of the machine where he has excellent visibility to the drum edges."
Newer roller designs also feature reduced noise levels compared to previous models. "There is a lot of work put into the [engine] hood and exhaust design to keep overall noise down and away from the operator," notes Dennison.
"The operator has to be happy," he adds. "The more comfortable we can keep the operator, the more productive [he or she] will be."
For more maintenance tips read the Featured Equipment Article "Impacts on Roller Life and Performance" in the May 2009 issue of Pavement Maintenance & Reconstruction.