By Alana Melanson
FITCHBURG — Imagine a thinner layer of pavement on roads that lasts longer than traditional asphalt, is less apt to crack and rut and costs significantly less than what municipalities are paying now.
Then imagine that this can be achieved by introducing finely ground recycled asphalt roof shingles and used tires into the paving mix.
According to Ed Naris of the Massachusetts Department of Transportation, the state has already already begun doing this as a preservation treatment on areas of select high-volume highways such as Interstate 91 and Routes 2 and 146.
State Sen. Jamie Eldridge, D-Acton, would like to see this option expanded to cities and towns as a means to save residents and municipalities money, increase the safety of roadways, create jobs and find uses for items that would otherwise end up in landfills.
Eldridge has filed a bill to create an Office of Clean Technology, which would focus on increasing clean technology sector businesses, jobs, research and development. He is also spearheading the Rubberized Asphalt Initiative, a movement to use these recycled materials in paving mix.
On Friday morning, Eldridge met with recycling industry representatives, MassDOT and other state and local officials to discuss the initiative and to tour the Recycle America facility in Fitchburg. As a
processor of used asphalt shingles, Recycle America, as well as Liberty Tire Recycling of Littleton, Roof Top Recycling of Boxboro and E.L. Harvey of Westboro, are poised to become a big part of the movement to use more recycled materials in paving.
“There’s the whole challenge of ‘what do we do with these asphalt shingles, what do we do with all these tires from cars across the country that are coming here to Massachusetts?'” Eldridge said. “There’s a whole market out there, and a whole lot of jobs out there in terms of recycled products.”
Approximately 250 million tires are discarded each year, said Paul Routhier, head of marketing and development for both Recycle America and Liberty Tire Recycling. According to Sean Anestis, CEO of Roof Top Recycling, only about 20 percent of the 250,000 to 350,000 tons of asphalt shingles discarded each year in Massachusetts are recycled.
In 2011, MassDOT increased the amount of recycled asphalt pavement permitted in surface courses from 10 to 15 percent, and is using ongoing research at the University of Massachusetts Dartmouth’s Highway Sustainability Research Center to improve the performance of paving mixes high in these materials. The agency has used approximately 300,000 tons of asphalt rubber pavements, recycling nearly 750,000 tires.
According Doug Carlson, vice president of asphalt products for Liberty Tire Recycling, who flew in from the company’s headquarters in Pittsburgh, Penn., for the meeting, the addition of rubber to the paving mix provides greater durability and flexibility to resist cracking. While adding recycled shingle asphalt alone to paving mix can tend to make pavement more likely to crack in cold weather, the inclusion of tire rubber reduces that brittleness, he said, allowing the use of more recycled asphalt and shingle in a mixture. It also expands the temperature range at which asphalt can perform, and reduces thermal cracking in winter, Carlson said.
The addition of tire rubber also makes for less noisy roadways, by decreasing the sound level by 11 to 14 decibels, Routhier said. It also makes for better friction, so roadways are safer, Eldridge said.
With a reduced thickness design, the savings for a consumer can be up to 50 percent, according to Carlson. Using rubber in place of chemical polymers overall can save about 15 percent otherwise, he said.
“It’s fantastic for consumers, fantastic for government, and it’s fantastic for the rubber industry just in general,” said Steve Forrest, general manager of Liberty Tire’s Littleton location. “It takes more tons out of the waste stream and into something that seems very organic. We’ve got tires on asphalt, now we’ve got tires in asphalt. The safety, the noise-pollution reduction, the cost benefit — it all seems to be a nice synergy.”
According to Carlson, the idea originally came from Phoenix, Ariz., engineer Charles McDonald in 1966, who realized the patching material he created lasted longer than the rest of the road. His mix was patented until 1995, but is now public-domain technology. Since then, it has spread to a total of 14 states, predominantly in the south, but he is expecting more to appear in the New England and Mid-Atlantic states over the next few years.