If the screed leaves a line in the mat, the roller operator is called on to smooth it out. Mat imperfections, divots, cool spots, anything that isn’t perfect gets left to the breakdown, intermediate and finish rollers to take care of. That means the compaction equipment must be in perfect working order, so the first half of this two-part series for bonus-worthy compaction practices includes a close-up view of the equipment. Here are some updated ideas—as well as some tried and true maintenance tips—for keeping the roller in good condition for every shift.
Let’s start with a new trend that original equipment manufacturers (OEMs) have embraced for you. Fewer mechanics are entering the work force each year.During the CONEXPO-CON/AGG tradeshow in March, Preston Ingalls, the president and CEO of TBR Strategies, took the stage as part of the CASE Construction Equipment “What’s Now” Speaker Series to share ideas for developing a proxy mechanic system to leverage the employees you already have on hand. He shared information with the audience that paints a grim picture of worker shortfalls—as it relates to trucking and construction technicians—over the next five years. “There’s less emphasis on pursuing a blue collar or trades job,” Ingalls said. “So with the shortfall of programs to attract people, or even prepare or train them, and not a lot of interest from the families to pursue that, we’ve got a reduced pipeline on the front end. That has a significant impact that’s only going to get worse.
“According to the Bureau of Labor Statistics, the construction and trucking industry will need to recruit 67,000 new technicians by 2022 just to meet the demand and replace retiring baby boomers. My generation….This number does not include the 75,000 new diesel engine specialists that the Bureau anticipates will be needed by then just for growth reasons.” What Ingalls showed was the vocation programs we still have in the United States graduate a little more than 10,000 aspiring technicians each year, which is far short of the 67,000 plus 75,000 we will soon need.
OEMs have responded by designing machines that require less routine maintenance, and by creating technologically advanced vehicles and systems that let operators and fleet managers know when they require attention. OEMs such as BOMAG, CASE, Caterpillar, Dynapac, Hamm, Topcon, Volvo and more offer telematics software that alerts the operator or owner or dealer—or a combination thereof—when routine and surprise roller maintenance is coming up. Predictive maintenance is now a buzzword.
Contractors can respond, Ingalls pointed out, by using a proxy tech. He defined a proxy tech as the equipment operator who also has responsibilities for performing certain maintenance or repair tasks.For many contractors, that’s been standard operating procedure since Day One. The roller operator performs a pre-shift cleaning and inspection of the asphalt compactor, greasing the grease points and cleaning the water system filters and spray nozzles. But Ingalls took that routine maintenance concept a step further.“Instead of waiting for the mechanic to arrive, we’re actually going to do something a little more creative,” Ingalls told the CONEXPO-CON/AGG audience. He shared how to create a proxy tech program by first developing:
- the tasks and boundaries each operator/proxy tech will be responsible for and limited to;
- the skills and knowledge the proxy tech will require for his tasks;
- the process to train and elevate proxy techs;• a screening and selection process to get the right talent;
- a tools/parts storehouse of appropriate resources;
- the appropriate parts to carry—the “uptime kit”;
- a means to evaluate how the proxy tech program is going;
- a way to “capture” what work has been performed;
- key performance indicators (KPIs) with baselines to prove the program’s value; and
- compensation packages/bonuses for proxy techs.
When Ingalls listed examples of tasks proxy techs can be trained to do, the list for roller operators looked familiar. The items we tell roller operators to check each day are already on his list. The same was true for pavers and milling machines, by the way. Asphalt professionals are already leaning toward the use of operators as proxy techs. When you ask the roller operator to replace a bent scraper bar and worn out cocoa mats, you’re getting work done without calling on a mechanic who may be dispatched to another site at that moment. The operator who knows how to clear a plugged spray nozzle saves the company time and money.
“Checking the scraper and sprinkler system is the step always missed by most operators,” Tim Hoffman, product manager for Dynapac Compaction Equipment, said. “But it is one of the most important things to remember. Having all the nozzles spraying and the scrapers adjusted correctly will ensure that the drum stays wet and will keep asphalt from sticking to the drum.”
Here are some tasks the valuable roller operator needs to take care of.
To Grease or Not to Grease
Newer models of compaction equipment offer fewer routine maintenance points than older models when it comes to greasing. In the real world, contractors have older machines on the job still putting in hour after hour of reliable service. Those old workhorses have maintenance needs, and if they include an articulating joint, there’s at least one point where greasing requires some caution.
John Ball of Top Quality Paving & Training, Manchester, New Hampshire, spent eight years as a roller operator for Pike Industries before he became the company’s director of training for 10 years. He shared that you will grease the nipple fitting on the top of the articulating joint at least once a week, if your machine has one. Don’t over-grease it, he cautioned, or you’ll have an area that attracts and pulls dirt and sand into the bearing. In fact, beware of over-greasing any points on older rollers for that reason.
Stop Mold Growth
“The water system is probably the most neglected maintenance item, yet the simplest thing to take care of,” Tim Kowalski said. He’s the applications support manager for Hamm, a Wirtgen Group Company, Nashville, Tennessee. He and Ball outlined the three-part filtering that water systems use to help operators keep sand, dirt or other impurities from mucking up the all-important spray nozzles. They also discussed how to maintain these areas.
- The first stop-gap measure is a sock-like filter in the filling tube, through which the water is pumped when you fill the tank. Kowalski warned that sometimes operators will want to remove this filter because it restricts flow. He advised against that. Saving a few minutes while you fill the tanks is not worth the hassle of extra cleaning and possible downtime due to big clogs later. Take the time to do things right and let the first filter do its job.
- Next, there’s a canister filter in the bottom of the tank, or on the side of the machine, which Kowalski referred to as the main filter for the system.
- Finally, there are micron filters on the spray tips. If water sits here too long, Kowalski said, it gets gummy or slimy. Keep these tips clean and clear by keeping the filters clean and clear. Ball recommended the operator remove the tips from the spray bar. Then make up a bottle of soapy water with a drop or two of Dawn dishwashing liquid. Dip a toothbrush into this solution to clean the filters. Run clear water over them and replace them for work. When the tips themselves need cleaning, use a welding tip cleaner to get into the crevices.
Even the tanks need cleaning. Kowalski reminded readers that the connecting tube between the tanks can clog as well. It seems logical when you look at it on paper, but when you’re in the field, the hustle and bustle of production can make an operator forget the simplest of tasks. For example, “If you have more than one pump on a roller, make sure you turn both on,” Kowalski said.
Both Ball and Kowalski wanted readers to think about water sources. “Water from fire hydrants has rust in it,” Kowalski said. “Water from ponds has algae that clogs up hoses.” They recommended the best way to keep rust or algae from doing its worst damage is to drain the tanks and clean them out.“If the roller’s going to be sitting for a while, drain it,” Kowalski said. “Especially in cold weather, treat the water with anti-freeze and drain it at the end of the shift.”
For cold weather, once the tanks are empty, Ball reminded operators to undo the hose, suck the anti-freeze up through the nozzles through the tips and into the lines.For regular maintenance: “Treat the water with chlorine about once a month, just like you would clean your swimming pool, and drain that out,” Ball said. “For some of the sticky mixes we have to compact, pour a bottle a Dawn in the full water tank to help lubricate the drum.”Experts advised operators use caution when selecting cleaning supplies.
“Chemicals in the tank often cause problems with the seals in the water pumps,” Dynapac’s Hoffman warned. He advised operators “check to make sure that anything put in the tank is safe for any kind of water pump.”
“The plastics used for the tanks are pretty chemical-resistant,” Kowalski said. “But you don’t want to use a petroleum-based product.”
The next area that experts agreed was vital for proper roller operation was the scraper system, and they agreed that operators need to pay more attention to the scrapers. Let’s start with the springs holding the scrapers against the drum. A savvy roller operator will have in his uptime kit a can of WD40 to lubricate the springs—or shock absorbers—at any point during the shift.
“You want the scrapers to move freely on and off the drum,” Kowalski said. This is vital when moving a dry drum. When it’s time to take the roller from one part of the job to another, you won’t run in vibratory mode and you’ll turn off the water system. At this time, why would you hold the scraper against a dry drum? To lift the scraper off the drum, you need enough play in the spring to release some of the tension or pressure.
Of course, the spring’s function is to put tension on the scraper bar. Ball warned readers that if it loosens, it won’t hold the bar in place. If the spring should fail, it must be addressed. “Either get a new one or tighten it,” Ball said. “If it’s too far sprung, just replace it. Keep a box of springs or small shock absorbers in the mechanic’s shed.”
For operation, the four scrapers work as a team. “When we’re rolling in one direction, two of the scrapers work as a water trough to put a thin film of water across the face of the drum,” Kowalski said. “The other two are keeping material off the drum. When we change direction, the scrapers change jobs.”
If a scraper is bent, it obviously can’t do its job. Ball spelled it out: “If the scraper bar is bent out of shape, the rubber part won’t be touching the steel drum, so it won’t be troughing the water anymore. You’ll run out of water.”
The rubber on the scraper bar is a wear item, so the operator will want to adjust it once a month, whether there’s a problem with the metal bar or not. To solve the problem of a bent scraper bar or worn rubber, follow these steps from Ball.
- Take out the holding pins.
- Take the scraper bar off the roller.
- Remove the rubber from the bar.
- Heat up the metal.
- Straighten the metal, if possible. If the metal cannot be unbent, replace it with a new scraper bar.
- Replace the rubber, if necessary.
- Reverse the steps to put the scraper bar assembly back in place.
Not all roller manufacturers install cocoa mats these days, but you can add them, and there are variations of the mats still in use in the field. They work in a similar fashion to the scraper bar, helping to lubricate the drum with water they absorb and distribute, and to scrape material from the drum’s surface. One type of roller that uses a cocoa mat is the pneumatic tire roller, and it has an important maintenance routine to remember. Think about the original material of a rubber tire and the original material in the asphalt mix—petroleum.
“At the end of the shift, when the tires are hot and the fibers of the cocoa mat have hot, sticky material embedded in them, lift the mat up off the tires before turning off the machine for the night,” Ball warned. “Do not leave the cocoa mats resting against the rubber tires while they cool off. The next morning, you will have a congealed mess to separate before you can work.”
The system AsphaltPro would like to draw attention to before we complete this installment of the “roll for bonus” series is the lights. Of course lighting is vital for nighttime paving, but even daytime projects benefit from strobe and beacon lights that catch the eye of the motorist speeding past your work zone. Ensure the lights on your drum edges, on the top of the canopy/ROPS, on the back and front of the machine, etc., are functioning properly. If a bulb is out, replace it before it’s a crisis.
Kowalski said, “Check these before you get out on the job.” He’s absolutely right. Once the rest of the paving and compaction train is half a mile up the road is no time to realize the finish roller has no strobe light to alert motorists to his presence.
While there are many routine maintenance points that roller operators instinctively know to check, such as the surface of the drums and the level indicators for all fluids, there are other areas that can slip a person’s mind when racing production. With the use of telematics and predictive maintenance systems, it’s easier to let the machine tell us what’s going on. Don’t let technology lull you into a state of complacency. Instead, put technology to work to get all the maintenance points checked each day. Use technology as one more tool in the uptime kit.
Next month, we’ll take the well-maintained roller into the field for best practices for bonus-worthy compaction.