“They placed the mix into a Blaw-Knox PF 6110 tracked paver with a Carlson IV screed directly from the truck,” Smith says. “The mix placed like hot mix but at cooler temperatures with no visible fumes.”
She says the Miozzi crew had both Ingersoll Rand DD-90 and DD-90HF rollers on site. “Breakdown was done at placement temperatures, roughly 250 degrees F. Finish rolling was done about 180 degrees F,” she says.
Smith says the entire job took a little more than two full days with work each day focused on paving. “It was slow going with a lot of driveway tie-ins, sewer covers, and tack placement. The road had already been prepped, so there was only the cleanup of sweeping the loose dirt and some cut-in to existing asphalt to make good joints,” Smith says. “In some instances the crew had to put down a leveling course in areas which required more attention.” She says the same WMA was used for both leveling and surface course.
“They did not need to rush to get it paving done and they did not make any alterations to the paving operation in order to complete the job,” Smith says.
Smith says the crew said equipment and tools handled the WMA the same as HMA “but with less fumes.”
Crew members said their skill set was the same as they needed for HMA. Skill set the same for hot mix asphalt. “However it does give a longer window, so compaction is better even at cooler temperatures.”
“This really was an incredible experience,” Miozzi says. “On top of the length of time between producing the material and then laying it down we experienced much lower emissions both at the plant and at the paving site on the island.”
Frank Perri, technical consultant hired by Block Island to inspect the job, came away impressed with the warm mix application.
“The material was applied in the same way,” Perri says. “The material, even after all that time, was very easy to work both in putting the asphalt down on the surface, the raking, the rolling. It was just as easy to work as I’ve seen in hot mix.
“In this case the main difference was that the temperatures taken at different points on the job and at different times throughout the work was significantly lower than what hot mix temperatures would have needed.”
Perri says he was surprised by the ability of the mix to retain heat as long as it did, especially considering it was produced at a lower temperature.
“Look, you couldn’t take hot mix and spend the travel time, much less store it overnight, without losing the heat needed to keep the material flexible and workable for your crews,” he says. “Reducing the material temperature is one thing but to sustain that working temperature for as long as this material was kept at is really outstanding.”
Smith says the Block Island project, which was the first warm mix asphalt job in Rhode Island, came off great. Not only were local officials pleased with the results but this entire process might have changed the way that they do any project needing asphalt in the future."