The hopper wing can provide insight into the care of the paver. If it is bent and the paint has come off, the machine was not taken care of properly.
A used asphalt paver can be a cost-effective option, provided it has been well maintained. Prior to purchase, be sure to conduct a thorough inspection of critical components that could impact performance and/or mat quality. (Image provided by Gencor.)
New paving machines offer advantages that make them a necessity in some mainline paving operations. However, most pavers offer very long, useful life cycles. In some applications, a pre-owned asphalt paver may offer the best choice for the job.
"If properly maintained, a paver can last up to 20 years," says Mark Bolick, quality control and service manager, LeeBoy. "But you need to service the paver and replace worn or broken parts as soon as possible."
Many 25-year-old, or older, machines are also still on the job. "Customers strip them down to the frame and rebuild them from the ground up," says John Sunkenberg, Volvo Construction Equipment. "If you are on top of your wear parts, and continually work on the hydraulic components, you can keep running them. If you are not going to do a lot of that work, then the machine isn't going to treat you well."
The life expectancy of a paver really depends on the maintenance program.
"With recommended maintenance, 7,000 to 8,000 hours is normal," says Terry Sharp, Caterpillar Paving. "It also depends on the composition of the asphalt mix. The type of rock and the amount of fines in the mix can lead to variations in component life."
Inspect along the material path
"When purchasing a used paver, there are many components that must be carefully inspected to ensure that you fully understand what you are buying," says Sharp. "Feeder system components such as floor plates, augers, conveyor chains and flight bars receive much of the abuse due to contact with the heat and abrasive nature of asphalt.
"Thin floor plates tend to warp, auger flights become pointed, conveyor chains start to sag, flight bars allow mix underneath and bearing seals become defective and allow mix to contaminate the internal components," he states. "These are just a few of the areas to make note of when inspecting the feeder system for defects." The quickest wear items are the components exposed to the material path. "Major wear components include floor plates, screed plates, auger flights, conveyor chain and bars, feeder bearings and the hopper flashing," says Brodie Hutchins, Vogele America.
"The material initially contacts the conveyor chain and deck plate," notes Sunkenberg. "That is probably where you have your greatest expense if replacements are needed, such as a new set of bearings, chains and deck plates." Next, is the auger. "The edges start to lose their thickness and overall diameter. They will also lose their effectiveness. As augers get worn down, they will not move material as well."
Be sure to check chains and flights for wear and stretch. "Check the bearings to make sure they are not loose on the auger," says Bolick. "Also check the thickness of the auger. The more they are used, the more they break down."
"When inspecting the augers, check for missing or damaged bearings and seals, bent or worn auger shafts, damaged supports and thin flights," says Sharp. "Worn auger flights can be indicated by streaks in the mat or sharp edges. If the castings and/or seals are damaged, mix can build up inside the chain case, which could cause more damage."
Screed condition impacts mat quality
Typically, the screed plate is the fastest wearing component. "All of the material put through that paver eventually passes under a screed plate," says Sunkenberg. "Depending upon the area, you will probably replace a set of screed plates every year or twice yearly. If you compare limestone to granite, the paver is going to wear quite a bit differently."
Screed plate wear can be a simple indicator of the shape of a screed. "Screed plates with visible wear near the front or rear can indicate improper setup or a twisted frame," Sharp explains. "Binding thickness control screws can indicate worn-out bushings. Extender tubes should also be inspected for scoring and accumulation of dirt and debris. Buildup will cause damage to the bushings."
With a diesel-heated screed, determine the condition of the heater boxes and screed frames. "The frames of the screed see a lot of fatigue because of the heating and cooling cycles," says Sunkenberg. "You are basically taking a diesel burner and scorching the metal. There are only so many times you can do that before the steel starts to rot, crack or lose its integrity."
With an older machine the heater boxes often rot. "The frame that you bolt the heater boxes up to will be cracked, fatigued or rotted away," says Sunkenberg.
According to Sharp, "Physical damage to strike-offs, extenders or end gates will be visually seen in the mat. Damage to electrical harnesses and heating elements can be easily checked with a meter. Tripped circuit breakers can indicate issues with the integrity of the system. If equipped with a diesel heating system, things to check include glow plugs, fans and switches."
Indicators of abuse
The hopper wing can provide insight into the care of the paver. "If it is clean and straight, the company took pride in the unit and ran it the right way," says Bolick."If it is bent and the paint has come off, the machine was not taken care of properly."
Hoppers take a lot of abuse due to truck exchanges, hopper inserts and heavy mixes. "The front hopper flashing on most pavers is probably the most exposed component on the paver - varying truck dump height and hopper overloading takes a toll on this material," says Sharp. "Push rollers and truck hitches also take abuse due to truck contact and visibility issues.
"Hopper inserts are designed to contain large, heavy quantities of mix, leading to increased stress on welds and hinges," he adds. "A good indicator of the structural integrity of the hopper is to look for rub marks on the bottom, outer side of the wings.
"If the wall thickness has been worn too thin, contact between the hopper and undercarriage can cause rub marks when the wings are folded down," he continues. "Check wall thickness to ensure that the hopper can still support the weight of inserts and mix."
"A flared-out hopper may cause a little bit more spillage than a hopper that has its original shape, but it should not be a huge performance issue," Sunkenberg states. "But a hopper will tell you the duty cycle a machine has gone through. If you pave a lot of cul-de-sacs and parking lots where the truck needs to turn out away from the paver, that is how you might bend up the hopper."
Also inspect the undercarriage. "Undercarriage components such as belts, planetary gears, drive wheels and bogies get exposed to abuse from uneven terrain, heavy loads and other hidden dangers," says Sharp.
"For continuous rubber track machines, the condition of the track must be considered," says Hutchins. "The condition of these parts can drastically change the value of a used machine."
"Belts must be carefully inspected to ensure that punctures and tears have not damaged the internal banding," says Sharp. "Many times, a visual inspection of the edge of the track belt can determine its overall shape. If cracks or exposed banding layers are present, failure may not be too far off.
"On wheeled machines," he continues, "the front bogie wheels are exposed to heavy loads and should be inspected for bent shafts. Oil samples of the planetary gears can expose contamination and are a good indicator of the condition of internal components."
Next, check the hydraulic system. Hydraulic components - such as feeder motors, vibration motors, etc. - may require replacement, depending on the age of the machine. "Typically, pumps and major powertrain components live as long as the machine when properly maintained," Hutchins notes.
Also make sure the hydraulic system is free of leaks and contamination.
"All hydraulic levels should be at specifications. Leaking seals could drip oil onto the paved surface, which could cause mat failures," says Sharp. "Oil samples and pressure readings can be useful for indicating whether pumps and motors are within the standard operating range. Cracked hoses should be replaced to avoid eventual failure at inopportune times."
"Always ask for maintenance records," adds Hutchins. "A history of fluid samples is fantastic if the previous owner was consistently maintaining the machine and taking fluid samples. A stand-alone sample at the time of the sale tells you nothing. Take pressure readings from the pumps, motors, etc. and check for any leaks or strange sounds."
Bolick agrees, adding, "The best thing to do is to check the service records to make sure the machine has been properly serviced."