The new runway at Chicago’s O’Hare International Airport set to debut in late 2015 could earn the nickname “Shingles,’’ and not because Chicago officials are hoping the number of flights will go through the roof. During the pouring of underpavement layers that began this month, O’Hare became the first U.S. airport to use recycled asphalt shingles in runway construction, according to the Federal Aviation Administration. It’s discarded material that in the past would have ended up in landfills, even though old asphalt shingles contain a valuable commodity — oil.
Old shingles getting new life at O’Hare, the first airport in U.S. to use recycled roof material on a runway. The two asphalt underlayers on the new O’Hare runway contain up to 3 percent oil, sand and fibers that were reclaimed from old asphalt shingles stripped off residential roofs in the Chicago area, officials said. The top layer is standard issue, a mixture called Portland cement concrete runway pavement. The old shingles are shredded to the consistency of coarsely ground coffee, then combined with virgin products to make a fresh asphalt mix, experts explained during a Chicago Tribune visit to a shingle recycling facility.
Roughly 9,500 tons of material repurposed from recycled asphalt shingles, or RAS, are going into the base of the 7,500-foot runway called 10 Right- 28 Left and on nearby taxiways and service roads on O’Hare’s south airfield.
The city, working with consultants and researchers at the University of Illinois, began experimenting with recycled roofing shingles in 2012. Once satisfied that the resulting mixture of recycled and new products met the strength and durability standards necessary to handle aircraft operations, the city sought and received FAA approval to modify the existing runway-construction standards in late 2012, said Jonathan Leach, chief operating officer at the city Aviation Department.
“It’s the right environmental thing to do.”
“It’s the right environmental thing to do,’’ Leach said last week at the department’s Quality Assurance and Material Testing Lab at O’Hare. He said the use of recycled shingles will be specified as a condition in all future paving contracts at O’Hare and Midway Airport. “The hope also is that as fuel costs rise, the recycled shingles will reduce some of our construction costs,’’ Leach said.
The Aviation Department estimated a cost savings of about $665,000 by using the recycled shingles for the new runway and on an adjacent taxiway project. It’s a relatively small amount compared with the $82.5 million paving contract for the runway-taxiway combination or the approximately $500 million overall price tag for the entire project, officials acknowledged.
But the FAA approval opens the door for using recycled asphalt shingles on other runways and taxiways, on blast pads where pilots conduct jet engine run-up tests and on public access and perimeter roads.
While O’Hare is the only U.S. airport to use recycled shingles, the concept has been a part of roadway construction for decades in other states, with the technology refined in recent years to produce a more consistent mix, according to experts.
Illinois was late to the party. In 2010, the state joined Wisconsin, Indiana, Missouri, Iowa and many states outside the Midwest that years earlier began to allow the recycling of asphalt shingles for use in road construction projects, under federal and state Environmental Protection Agency rules.
Illinois followed up last year by banning most shingles from being dumped into landfills. The law that took effect this year forbids any landfill within 25 miles of a recycled shingle facility from accepting shingles unless they are contaminated with other materials.
Roofing contractors have a financial incentive to recycle old shingles because the fees to dump the material at landfills are about $45 per ton versus $15 per ton at a recycling center. Recycling facilities do not accept shingles manufactured several decades ago, when cancer-causing asbestos was commonly used in home building materials, officials said.
In addition to the environmental benefits, another big advantage is that the use of recycled shingles helps to conserve resources and reduce costs, which, in turn, can help stretch road construction budgets, officials said. But the various agencies say it’s difficult to quantify the cost savings. CDOT pegged average savings at 2 to 3 percent, while the Tollway said recycled shingle use generates an estimated 8.5 percent savings in overall asphalt construction costs; IDOT claims a savings of up to 15 percent compared to mixes without the shingles.
In Chicago, about 90 percent of the pavement resurfacing projects conducted last year used some amount of recycled shingles, CDOT said. The roof on a typical Chicago bungalow contains 6,000 pounds of shingles that, when recycled, help produce 400 feet of road. The shingles from about 100 homes are equivalent to about 400 barrels of oil saved, because shingles contain 25 to 30 percent oil. The goal of the recycling process is to retain most of the oil in the finished product, which is used as a binder in roads, officials said.
Virgin liquid asphalt, depending on the grade, costs about $600 per ton, while the recycled shingle mixture sells for about $50 per ton. It is estimated that $36 million to $60 million could have been saved in Illinois last year if recycled shingles were used on all road projects in the state.
India’s “Plastic Man” Turns Litter Into Paved Roads
Meanwhile, halfway across the globe from one of the world’s busiest airports, as far as the eye can see, there’s stinking, smoking, untreated garbage. It’s concentrated in the municipal dump, in the South Indian city of Madurai. The surrounding fields are also piled with trash.
The road to the dump, and beyond it to Madurai’s airport, is like a Hollywood vision of dystopian ruin: lifeless, black, choked with human refuse.
It is difficult to exaggerate India’s garbage problem. Jairam Ramesh, the nation’s former environment minister, has said that if there were a “Nobel prize for dirt and filth,” India would win it. As much as 40 percent of the country’s municipal waste remains uncollected, according to the Organization for Economic Co-operation and Development. Of the waste that is collected, almost none is recycled. Most of it sits in open dumps such as the one in Madurai, leaching into the soil and contaminating groundwater. Some of it is burned, releasing dioxins and other toxic chemicals into the air.
Much of India’s garbage is made up of plastic — a scourge of the nation’s new consumer economy. The country’s Central Pollution Control Board says more than 15,000 tons of plastic waste are generated daily. Although the nation’s per capita consumption of plastic is low compared with that of the U.S., it’s expected to double over the next five years as India continues to develop. This poses huge environmental, social, and economic challenges. As the Supreme Court of India recently observed: “We are sitting on a plastic time bomb.”
But chemist Rajagopalan Vasudevan sees an opportunity. A professor of chemistry at Thiagarajar College of Engineering, near Madurai, he insists that plastic gets a bad rap. Rather than an incipient environmental calamity, plastic, in Vasudevan’s opinion, is a “gift from the gods”; it’s up to humans to use it wisely. And he’s devised a way to transform common plastic litter — not only thicker acrylics and bottles but also grocery bags and wrappers — into a partial substitute for bitumen in asphalt.
In recent years his method has been gaining recognition. He’s become known as “Plastic Man” and travels throughout India instructing engineers how to apply it. The college holds a patent for his technique but often licenses it for free. To date, more than 5,000 kilometers (3,000 miles) of plastic roads have been laid in at least 11 states. The Central Pollution Control Board and the Indian Roads Congress, two leading government bodies, have endorsed the method.
Almitra Patel, one of India’s leading experts on garbage, who has advised several state governments on their waste policies, considers Vasudevan’s technology a “win-win-win.” It consumes an unwanted and mostly nonrecyclable resource; it results in stronger roads; and because it replaces as much as 15 percent of more expensive bitumen in the mix used to lay roads, the technology also holds the potential to lower the cost of infrastructure.
She adds that one of the chief advantages of Vasudevan’s method is that it can accommodate the multilayered wrappings often used to pack snacks such as chips and cookies. These wrappings (typically consisting of a layer each of plastic, polyester, and aluminum) make up an increasingly large volume of waste in the country. They’re just about impossible to recycle, but they can easily be shredded and reused in Vasudevan’s roads. “It’s really a wonderful situation,” Patel says. “I think it is an absolutely transformational technology that could clean up India overnight.”
Another advantage of Vasudevan’s method is its simplicity. It requires no significant technical knowledge and no large investments or changes to existing road-laying procedures. His whole operation is a good example of the Indian method known as jugaad, or “frugal innovation.” Jugaad makes a virtue of necessity: It extols the work-around, the shortcut that uses (and sometimes improves on) limited resources. “I do it all the Indian way,” Vasudevan says. “What is the use to spend thousands of rupees when we can do it much more cheaply?”
Vasudevan talks about the economic barriers that stand in the way of large-scale adoption of his method, such as inefficient markets for plastic and contractors who may not believe it’s in their best interest to build more sustainable roads. “I have to discover a technology not only to change the use of plastic,” he says, running his hand through his thinning hair and smiling, “but also to change human minds.”
Sources: Chicago Tribune, Bloomberg Business Week