A poorly trained or inexperienced operator can have the opposite affect. "Improper operation or abuse can significantly decrease a roller's longevity and is one of the most important factors in influencing a roller's life span," says Perez. "Abusive operation will, over time, result in potential premature failures." For example, repeated misuse of the emergency stop functions will rapidly increase wear on brake and engine components.
Failing to recognize when material has achieved density is perhaps the most common contributor to premature vibratory roller failure. As Monical explains, a vibratory compactor is intrinsically designed to "jump" up and down on material. Material that is not yet compacted has sufficient "give" to absorb some of the shock wave produced. However, once the material has achieved density, all of the shock wave is transferred back into the machine. Continued over compaction of the surface not only wastes fuel, it accelerates wear on the roller.
"When you have energy transferred back to the roller, it's going to cause more fatigue and stress on the structural integrity of the machine," Detrich points out.
Operating the roller at the improper setting can have similar repercussions. In this case, the drum can often serve as a visual indicator of whether the roller has been misapplied.
"A sign of bad practice is when you see uneven wear on the drum," says Anand Chaturvedi, marketing manager for soil compactors, Ingersoll Rand. "Average wear occurs uniformly across the circumference of the drum over a period of time. But if there is something abnormal or uncommon, that will tell you something about how the machine has been used or abused."
Large indentations in the drum can indicate the machine is being used at the wrong frequency or amplitude setting. "Say you're compacting a base material and you really need to be on amplitude setting 2 and you're in amplitude setting 4," says Detrich. "If you continue to beat the same area over and over, you could consequently create damage to that drum — not just externally, but internally, as well."
Indentations can also be a sign the roller is being used for the wrong application. "You might see a smaller size machine on a rock fill application. That might not be the right machine for the task," notes Chaturvedi. "You might need a heavier machine or a larger horsepower machine."
"Probably the worst-case scenario," says Monical, "would be a tandem drum asphalt compactor that accidentally — or on purpose — is used in a rock environment. The drum conceivably could be pitted, and then it's taken back onto an asphalt job. The pits or impressions in the drum will be transferred into that asphalt material."
Crews need to avoid the temptation to make do with a machine not intended for the particular application. "Bear in mind that there is a tradeoff if you are trying to achieve something from a machine that it is not made for," Chaturvedi stresses.
Spot problems early
A daily walkaround inspection of the roller prior to use should be a required part of an operator's job. Monical advises checking to ensure the engine has sufficient oil; the air filter is clean; the machine is fueled and the fuel filter is clean; and the hydraulic filter does not require changing. "It takes five minutes or less to just make sure everything is okay," he states.
The daily walkaround is also a good time to check for signs of oil or hydraulic leaks, as well as any damage to the roller.
In addition, the operator should be trained to recognize signs of trouble during operation. Examples include engine draw down, reduced steering response or low vpm. "The operator needs to have some technical expertise to know if the machine is operating properly," says Detrich. "Has he noticed a lack of performance? If he has, what could be causing it?"
The ability to recognize a decline in performance will allow the operator to report the situation and have the problem checked out before it turns into a much larger problem, Detrich points out.
Dennison adds, "An operator who will recognize and report any machine damage or operational deficiencies found in the course of daily machine inspections performs a vital and valuable function for the contractor."