As manufacturers have made infrared equipment more mobile and versatile, contractors have taken infrared use in new directions." I look at the American contractor as one of the most inventive and innovative people around because contractors have to find ways to do things more quickly and more profitably and better than they were done before," says Dave Strassman, Asphalt Reheat Systems."That's one of the things we see happening in infrared use." While each of the following jobs was explained by a particular manufacturer, all infrared equipment can perform these and other types of work.
Installing thermoplastic crosswalks at the University of Wisconsin
Not everything involved with the infrared process has to be a pavement repair, and a recent thermoplastic crosswalk installation on the University of Wisconsin-Madison campus is a perfect example.
Dave Strassman, development officer at Asphalt Reheat Systems, says the company not only applied thermoplastic (in the university's red and white school colors and with reflective glass beads) to a crosswalk, but they also used infrared process to install a Bucky Badger mascot logo to the middle of the crosswalk.
"It was an older intersection, about six to eight years old, Strassman says." It had been striped before with some thermoplastic, some epoxy, and some paint so the first thing we had to do was remove the old markings."
Using their Manta Ray infrared unit, ARS heated the pavement to between 300 and 325 degrees F, just enough to soften the markings. Then they used a rake to pull off the epoxy and paint. To remove the heated thermoplastic ARS attached a bucket razor to a Bobcat skid steer and peeled the marking right off the surface.
At that point ARS had the crosswalk area, which measured 45 feet long and 6 feet wide, back to its original fresh asphalt surface. Strassman says they used the self-propelled Manta Ray unit to reheat the crosswalk area.
"The self-propelled unit is helpful in instances like this because we can place it within inches of where we need the heat. It's easily operated by one person and can maneuver over the precise area within inches ," Strassman says."That's one of the big advantages of the newer infrared units: They are much more maneuverable."
Following standard infrared processes, ARS heated the area, then placed a plastic-and-rubber crosswalk template on the surface. Using a plate compactor they stamped the template 1/8 inch deep into the hot asphalt surface. Once the template was removed there was an indented crosswalk remaining in the pavement. Using red and white thermoplastic ARS completed the job. Thermoplastic was placed in the indentations, then the Manta Ray was used to heat it to between 250 and 275 degrees F, until the material starts to melt.
"The Manta Ray has a timer on the outside and we can monitor the heat that way,"Strassman says. "We know it takes about two minutes to bring the temperature to between 250 and 275 degrees F."
He says they also used a temperature gun to monitor the heat.
"You can also simply raise up the heater and visually inspect the thermoplastic as it's heating," he says."Raising it up doesn't affect the process."
Once the material has been heated and then cooled, it's almost flush with the pavement surface.
"We needed it recessed a little bit to prevent damage to the crosswalk from snow plows and heavy traffic," Strassman says.
The same process was used for the Bucky Badger logo.
"We did all this while classes were going on, and this is in a very high-traffic area of campus. There were probably close to 3,000 students walking by us while we were out there working," Strassman says.
Strassman says he expects infrared application of thermoplastic to become widespread for a number of reasons, including the fact that it's easier, faster, and more consistent to do than the traditional approach, which would have heated the material with a hand torch.