Asphalt Shingle Recycling

For the past 25 years, recycled asphalt shingles have proven to be a valuable additive to asphalt pavement. But valuation as an additive does not address the actual value as a commodity.


The current benefits of recycling shingles are: diversion from landfills, replacement of aggregates in asphalt, and improved rutting performance. But one of the most obvious and most valuable benefits is being missed. On average, post-consumer asphalt shingles contain 25% - 30% by weight asphalt cement or bitumen. 

 

Bitumen is refined from a finite and expensive resource—OIL. 11 million tons of asphalt roofing shingles are discarded each year in landfills, this translates into 2,750,000 tons or $1.6 Billion dollars’ worth of bitumen or Oil buried each year in Americas landfills.  That’s Right! We can actually say that we bury $1.6 Billion Dollars’ worth of oil per year. Why is this valuable commodity still being treated as a waste product?


While the value of waste shingles as an additive has been well established, a main deterrent to recycling waste shingles is the low value asphalt plant operators place on waste shingles as a commodity. There are approximately 4000 hot mix plants in the U.S producing more than 500 million tons of asphalt per year. The common belief is that “because shingles are waste, they have no intrinsic value.” This belief, based on “the way things have always been done,” helps to maintain an artificial low value for waste shingles as a commodity. Prior to 1975 it was considered waste due to the use of asbestos in shingles. It took until this decade to rid the country of asbestos produced shingles and a new market has begun.


A few forward thinking hot mix asphalt operators are currently using waste shingles as an under-valued commodity in a very competitive industry. The opportunity for a plant manager to save his or her company significant dollars per year, should have them lining up to get this significantly undervalued commodity while it lasts.
In 2009, American Association of State Highway and Transportation Officials (AASHTO) approved specifications for processing and blending waste shingles in asphalt pavement.  The AASHTO approval is a very important advancement for the goal of recycling waste shingles.

 

Uses for processed Shingles

Hot Mix Asphalt shingles, which account for two-thirds of the U.S. residential roofing market, are made from a fiberglass or organic backing, asphalt cement, a sand-like aggregate and mineral fillers such as limestone dolomite and silica. These are the basic ingredients of hot-mix asphalt used in road construction, which helps explain why the paving industry is the No. 1 end user of reprocessed shingles.


Cold patch for repairing potholes. Ground-up shingles mixed with aggregate and an emulsion can be used for patching roads. In fact, the mix actually improves road strength because of the fiberglass or cellulose content of the shingles.

 

Aggregate in road construction. Ground and screened shingles can be mixed with gravel and used to cover unpaved roads, minimizing dust, reducing vehicle noise and longer road life. Combined with ground asphalt and concrete, ground shingles also make a good road base for driveways.

 

Manufacturing new shingles. Some shingle manufacturers have tried using factory scraps to make new shingles, with mixed success.

 

Energy recovery. Shingles have an energy content of as much as 20,000 Btu per pound and the practice of using scrap as a fuel supplement is an established market in Europe. Some industries like cement manufacturers in the USA, are using old shingles as fuel.