Application Tips: Small asphalt pavers

Asphalt pavers with operating weights of less than 19,000 pounds can be used to pave everything from bicycle paths to municipal streets and large department store parking lots. The trick to deciding what size and type of paver you need is often less about the kinds of jobs you are doing and more about how many tons of asphalt you want to put down per day, says Steve Simons, marketing manager for LeeBoy.

“You can use these pavers for a variety of jobs,” he says. “What matters is how many of those jobs you want to do.”

If you want to put down 100 to 400 tons per day, Simons recommends a gravity-fed paver, which, in most cases, will weigh less than 10,000 pounds. For 500 to 1,500 tons per day, he suggests a larger, conveyor-type paver.

“A conveyor machine is more for continuous paving applications where you’re paving a larger parking lot or any kind of road,” says Patrick Wakefield, product marketing manager for commercial paving products, Ingersoll-Rand.

The features and benefits of a conveyor-fed machine are in the ability to put material down faster, says Glen Calder, vice president of operations for Calder Brothers, maker of Mauldin pavers. “But if you’re a small contractor with one or two dump trucks, you can’t get the material to the job fast enough to feed a conveyor machine unless you’re renting a lot of trucks,” he says. “So a lot of the sizing of the machine is related to how fast you can get asphalt to the job.”

Compared to gravity-fed pavers, conveyor models generally have a larger hopper capacity, more horsepower and a faster travel speed and are more productive for those reasons, says Steve Wilson, product manager for Bomag Americas. Some also have wider and heavier screeds, Calder adds. Heavier screeds will deliver a more dense, higher quality mat.

Gravity-fed units work well in applications such as driveways or in a tight fit situation such as a small commercial lot where you don’t have room to push a truck. “Gravity-fed models are quite effective in all low-production-demand type jobs,” Wilson says. “It’s a good first paver for the contractor just starting out.”

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One of the benefits of a gravity-fed machine is that it is simpler by design – there’s no moving conveyor that needs daily, weekly and yearly maintenance, Wakefield says. So maintenance costs are lower and the initial acquisition cost is lower as well.

TIP: Compared to gravity-fed pavers, conveyor models generally have a larger hopper capacity, more horsepower and a faster travel speed and are more productive for those reasons.

Before you buy
If you haven’t purchased an asphalt paver in this size class during the past five years, there are some new features you should be aware of and some optional features that have become standard.

Electric-over-hydraulic controls like those on highway-class pavers have replaced joystick or lever controls on the larger machines in this class. Dual panels, which allow operation from either side of the paver, are easier and safer to operate, Wakefield says.

Sonic feed control, which used to be optional, is now standard on most larger machines. A sonic sensor mounted on the screed extension monitors the rising and falling of the asphalt and signals the augers to feed more asphalt or stop feeding it when necessary. “It’s just an automatic control of something that’s normally manual,” Simons says. “It makes it easier on the operator.”

In 2004 Calder Brothers patented a self-adjusting screed that maintains a relationship between the extension and the main screed, allowing you to pave seamlessly, Calder says.

Most manufacturers are also making more machines with joint matcher or grade systems, which maintain depth automatically. The ease of implementation for these systems has increased significantly in the past five years, Calder says. While a grade system is still an optional feature that costs from $5,000 to $6,000, it’s becoming more common. “As contractors fight the battle of finding capable, trained crew, many of them find it’s worth the money to use a system that will run your depth for you automatically,” Calder says.

Many manufacturers are bringing technology from highway-class pavers down to their small paver lines. “What you’ll see is a move to make all the pavers in this class more durable and have a longer life than what we’ve seen in the past,” Wakefield says. For example, Ingersoll-Rand has increased the material thickness of its pavers’ main frame to give the machines a sturdier foundation. Thicker hopper wings are less likely to get bent up when they come into contact with trucks. The machines also have a wider stance and lower hopper deck, which increases the range of truck sizes that can be used to feed the paver.

Because of their residential and municipal use, small asphalt pavers’ engines are usually encapsulated now to make them quieter. Rubber tracks instead of steel tracks give you a smoother mat and more traction.

TIP: Clearly delegate who is responsible for setting up the paver at the site.

Operation advice
Your paving crew has a lot to do with the life of your equipment and the quality of your jobs. “The best advertising any contractor has is the past jobs he’s done,” Simons says. “Because they sit there and everybody drives right over them or parks on them. If people say, ‘I remember so-and-so contractor did this parking lot last year and it’s full of potholes,’ that will come back to haunt them.”

A paver is a precise piece of equipment that requires trained and experienced operators in order to achieve a good result, Wilson says. Most paver distributors offer training and start-up instruction free of charge. Some manufacturers also offer in-depth classes, usually at a cost. But Wakefield says the price is marginal compared to the paver acquisition costs and the long-term benefits.

Make sure you or your employees operate the paver within the original scope of its design; don’t try to make it do something it wasn’t intended to do, Wilson says.

Clearly delegate who is responsible for setting up the paver once it gets to the site. “Some contractors aren’t as clear as others in terms of whose job it is to light the burners, get the screed heated up, make sure there’s fuel for the day, check the oil and perform all the pre-job work,” Calder says. “They need to be extremely clear that there’s one person responsible for all those items and he knows it and whoever is running the job knows it.”

Plan your jobs ahead of time. Know when the asphalt is going to be there so it doesn’t get cold while you’re waiting for the paver or for someone to do some grading.

When asphalt is dumped into the paver, it should be between 260 degrees and 290 degrees Fahrenheit. If the asphalt is cooler than 260 degrees, it won’t compact as well, Simons says.

If there is a delay in the arrival of a truck, check the screed to make sure it has maintained its temperature. A low screed temperature could cause quality problems with the mat, so you might need to heat it again, Wakefield says. When changing trucks, keep a full head of material in front of your screed, Calder says. Running completely out causes the screed to dive, creating a low spot in the mat.

Instead of backing the truck up to the paver, stop the truck and then drive the paver to it. “If you hit the paver with the truck, it bumps the paver back and makes a mark on your mat that you probably won’t be able to get out,” Simons says.

Maintain a paving depth of no less than three times the aggregate size in the asphalt, Wakefield says. Otherwise, you could experience quality issues with the mat. Over-adjusting the screed is a frequent operator error, Calder says. Some operators expect to see an immediate reaction when they make a depth adjustment. “If they don’t see it right away, then they’ll keep adjusting,” Calder says. “When the screed does fully correct, it will go too far one way or the other and they’ll have to crank it back up or back down. So they end up yo-yoing.” The total impact of depth adjustment isn’t apparent until after five full lengths of the screed arm, he says.

And finally, don’t underestimate the importance of rollers and compactors in the job’s quality. Simons says LeeBoy’s philosophy is the asphalt is never too hot to start rolling. “Some people like to wait until it’s cooler, but when it’s cooler, it’s starting to settle already and you get less compaction than you’d like,” he says. Simons recommends going over the mat first with a steel-drummed roller, then a pneumatic-tire roller followed by the steel roller again.

Brutal conditions
Maintenance of a paver is extremely important because it has so many wear parts. “You’ve got conveyors turning, you’ve got augers spinning and screeds extending in and out,” Simons says. “If you take good care of those things, keep them cleaned and greased, follow the maintenance schedule, they’ll last longer.”

Perform daily maintenance inspections and repair anything found to be suspect or broken, Wilson says. Make sure asphalt doesn’t cool and harden under the screed, in the hopper or on the conveyor and augers. Before you begin paving, spray an environmentally friendly releasing agent on areas that will come in contact with asphalt. It will prevent material from sticking as much. You can also use a cutting agent to help remove asphalt at the end of the day.

Poor maintenance and not cleaning the machine are the most common mistakes Wakefield says he’s seen contractors make with small asphalt pavers. “A paving job is probably the worst conditions for any piece of construction equipment to go through,” he says. “With the stress of the asphalt coming through the machine and the heat of it, proper maintenance is imperative.”