Ring Road Recycling (RRR) is a clean technology firm specializing in asphalt shingle recycling. Recycled asphalt shingles are used in the following applications;

  • In asphalt pavement to replace virgin asphalt cement
  • In gravelled yards as dust control
  • In cold road patch for pothole repair

Background on shingle recycling

Shingle Composition

Asphalt roofing shingles are made of a felt or fiberglass mat saturated with asphalt and surfaced with granule. Composition is:

  • Asphalt cement: 18 to 35 percent by mass. This is what provides the water shedding characteristic of a shingle. It is also the adhesive that holds all the components together.
  • Mineral filler/stabilizer: 20 to 45 percent. This is added to the asphalt cement to increase the shingle’s weight and make it less susceptible to wind damage.
  • Granule, which is ceramic-coated rock: 20 to 35 percent. This protects the asphalt cement from solar degradation. It also allows for coloring the shingle in various attractive hues.
  • Mat: 5 to 15 percent. This is the structure on which the other components are secured. Shingles are now made on a fiberglass mat, but formerly the mat was cellulose (cardboard).

Waste Stream Composition

Shingles in the waste stream can be either tear-off or manufacturer’s scrap.

Tear-off Shingle
The majority of waste shingles are postconsumer waste: tear-offs from re-roof jobs. A roof is replaced roughly every 20 years. In the past old roofs were often covered with new shingles without tearing off the old shingles, so some tear-offs include multiple layers of shingle for disposal.

Manufacturer’s Scrap
When shingles are manufactured, tabs and trims are cut out to shape the shingles for assembly. These tabs are discarded, along with new shingles that did not meet quality standards.

Processing Steps

To prepare waste shingles for a recycled use, the shingles need to be processed according to end use specifications. This typically includes sorting out non-shingle debris and grinding the shingle for the specific end use application.

Sorting
Shingle is decontaminated at intake by handsorting and later with a sort line on a conveyor. All non-shingle must be removed so as to leave a stream of clean shingle for grinding.

Grinding
Shingle is ground to 10 mm minus (3/8″ minus) using a shingle grinder. As it is conveyed off of the grinder it passes under a cross-belt magnet which removes all the nails. Now the shingle is RAS (Recycled Asphalt Shingle).

Grading
Depending on the use, the RAS may be screened after grinding to conform to grading requirements.