Of the estimated 11 million tons of
oil-based tear-off asphalt roof shingles generated annually in
the United States, nearly 10 million are landfilled. However,
if fully recycled, they would help reduce oil consumption and
greenhouse gases, and lengthen the lifespan of C&D landfills.
Almost 1 million tons of this material are recycled to provide
feedstock for asphalt hot mix producers.
“Shingles are just ripe for the plucking,” said Bill Turley,
president of the Construction Material Recycling Association
(CMRA). “If we used all of it, we could easily set up a system
to do it.”
Between 25 and 35 percent of a typical shingle consists of oil.
Interest in using shingles is growing and last November at the
CMRA’s 4th Shingle Recycling Forum, 381 people attended, compared
to 240 at the 2007 forum.
“The reason is simple – the economic benefits are becoming very
obvious to many, especially hot mix asphalt plant operators,”
said Turley. “They save tremendously when using shingles to replace
new virgin bitumen to their mixes, especially since the price
of new bitumen has soared in recent years. But plant operators
are reluctant to tell the shingle recyclers what value their
shingles have, as they are still trying to get the recycled shingles
for a very low price.”
Many of the new attendees were representatives of hot mix producers.
“The number of states that accept this material and the amount
of research into utilizing it has reached a critical mass,” said
Turley, “and now people are beginning to say this is no longer
R&D, it is something I can implement myself. While not accepted
in every state, asphalt made with recycled shingles is gaining
acceptance and there is enough research to back it up so that
people who are generally reluctant to try something new are willing
to give it a try.”
This is good news to recyclers as the market for shingles now
has a solid base from which to expand.
Dan Krivit, a co-organizer of the 4th Shingle Recycling Forum
and senior project manager with Foth Infrastructure & Environment,
LLC, a Minnesota-based engineering and environmental consulting
firm, said, “Given the high oil content of shingles, it can save
$2 to $4 per finished hot mix ton. The bidding for paving work
and supplying hot mix asphalt for the trucks is competitive and
the savings are significant.
“If you multiply the savings against all the tons that are used
on roads, millions could be saved and when contracts become more
competitive, the savings will be passed along. Recycling shingles
makes great economic and environmental sense – it reduces GHG
emissions because that is oil that doesn’t need to be refined,
purchased and added to hot mix. But the interest in shingles
has been much steadier than the rising price of oil.”
He added that in the worst case, roofing contractors or haulers
pay the same amount as a tipping fee charged at a landfill to
bring shingles to recycling centers, but that many people are
now enjoying a 50 percent savings by taking the material to recyclers.
“Ultimately this means jobs and economic benefits that are spread
across the system,” said Krivit.
There is an American Association of State Highway Transportation
Officials (AASHTO) specification for the use of shingles in hot
mix for roads, and the CMRA is pushing a similar specification
through the American Society of Testing Materials.
“The Federal Highway Administration is highly supportive of the
use of recycled shingles – they know it makes economic sense
and has engineering benefits,” said Turley, “but it does not
have control over the specifications. They can only advise and
advocate their use.”
Krivit is working with states that have approved the use of shingles
and those looking to do so.
“AASHTO, which was developed in 1996, was amended in 2009,” he
said. “It is generally viewed only as guidelines by the states,
but it does provide the context and a peer reviewed starting
The Departments of Transportation (DOT’s) in Minnesota, Iowa,
New Hampshire and Wisconsin, he added, have just approved the
use of tear-offs in manufacturers specs.
“If the DOT adopts the spec, then the market is ready to take
off,” said Krivit. “Since 1986 Minnesota has had a spec for the
use of manufacturers shingle scrap, but as of January 1, 2010
the Minnesota DOT now allows, on a permissive basis, tear-offs.
The Illinois Tolling Authority has also been working to demonstrate
the use of recycled asphalt shingles (RAS) in its hot mix asphalt
(HMA) pavements. But Missouri has been the real leader, adopting
and implementing its first permissive spec for tear-off RAS in
HMA over six years ago.”
Turley added that California and Oregon are looking into allowing
tear-offs and that Colorado just conducted a positive pilot project.
Canada is also jumping on the bandwagon. Ontario has a spec for
manufactured scrap shingles and is looking to add tear-offs.
Nova Scotia has allowed tear-off shingles and British Columbia
and Manitoba are considering specs.
Interest in shingles has led to states and cities initiating
pilot projects, with at least 24 being planned for 2010 and investments
to promote the development of markets for shingle.
“Most governments are trying to be as green as possible and have
sustainable purchasing policies and there are examples of states
and cities purchasing hot mix specifically to help stimulate
the market for tear-offs,” said Krivit, “so if it costs no more
than a virgin product, they’ll give a preference to a recycled
product. This is the case for copy paper and other products,
but it will eventually trickle down to highway departments. They
are already purchasing recycled asphalt pavements – the big brother
of recycled asphalt shingles.
Asphalt shingle manufacturing plants are doing their part by
either recycling the castoffs on-site or selling the scrap to
hot mix plants, who bid for the product.
“The same will happen with tear-offs in 5 to 10 years,” said
Krivit. “We are close to tear-offs becoming a commodity.”
Turley said it’s not necessary for hot mix producers to unite
to purchase tear-offs as the savings are proven and they generally
do not want to share any information on production costs with
their nearby competitors.
A major barrier to using recycled shingles is the asbestos issue.
Prior to around 1975, some shingles were manufactured with asbestos
in them. As a result many regulators have been afraid to allow
grinding of tear-offs because of a fear the asbestos would become
“But many state regulatory agencies have developed protocols
to assuage these fears, and that is helping open up the market,”
said Turley, who stresses that asbestos “hasn’t been used in
more than 30 years, so there are hardly any shingles with asbestos
left out there. A CMRA member has done nearly 100,000 polarized
light microscopy tests and has had only 16 hits for asbestos.
It’s rare, but regulators are still concerned and they are going
to require testing. Fortunately in the states and provinces with
higher tipping fees recycling shingles still makes economic sense,
despite the testing requirement, to do the tests.”
The United States Environmental Protection Agency (EPA) and state
environmental agencies are helping to promote shingle recycling,
especially via the CMRA, which is working with the EPA to help
spread the word.
Turley said that more and more legislators are aware of the benefits
of recycling shingles and working with the industry.
“As a general rule engineers are cautious – they don’t want to
take chances until a new product is fully proven. Once they have
the opportunity to review the wealth of research and development
project results, they often realize that shingle recycling is
feasible and can help lower costs of our public highways. We
are finding a lot of support.”
He added that while there are other potential market applications
that are theoretically possible, the immediate future for shingles
rests with hot mix production. However, while some states allow
hot mix with recycled content, individual states still insist
upon conducting their own pilot projects before giving the green
“There is a federal ‘pooled fund study’ led by Missouri DOT,
so there is cooperation going on between the states,” said Krivit,
“but in general, the states do their own thing. There are legitimate
engineering reasons for this – differences between southern and
northern climates, which require specific mixes for asphalt.”
Krivit noted that highway pavement engineers use a variety of
performance tests, including density and smoothness, to ensure
that asphalt made with recycled materials meets the same standards
as traditional asphalt mix.