A typical asphalt shingle is a composite product comprising an asphalt-impregnated mat within a granular / aggregate surface. The mat is the matrix that supports the other components. This is usually a composite of fine fibreglass filaments mixed with water to form a pulp.
The asphalt produced during petrol refining provides a water-proofing surface while increasing stability under extreme temperatures. A granular, usually ceramic coating protects the upper side of the shingle from solar damage, while adding a colour tint. While the bottom surface has a coat of sand, talc, or fine particles of mica.
Management and Recycling of Asphalt Shingle Waste
There are two types of waste according to the Construction & Demolition Recycling Association. These are post-manufacture scrap, and post-consumer tear-off when the shingles have exceeded their useful life. The latter, which accounts for the bulk of demand for recycling of asphalt shingles, is largely the result of construction, demolition, and renovation activities.
Post-consumer tear-down scrap often arrives at a recycling yard mixed with other materials that must first be separated away. The shingles are typically upward of fifteen years old, and in varying stages of decomposition. They may also comprise several layers laid one over the other during the lifetime of a building.
Preparing Asphalt Shingle Scrap Before Recycling
1… The first stage involves physically separating non-shingle waste
2… The cleansed waste is then size-reduced prior to shredding
3… Magnets remove metal fragments from attachment methods
4… Finally, blowers / vacuums remove lightweight contaminants
The deconstructed asphalt singles become inputs to beneficial processes. These include hot mix asphalt pavements, cold asphalt patching on roads, dust control for rural roads, temporary roads and driveways, as a road / driveway aggregate base, in new shingle manufacturing, and as a fuel supplement in cement kilns.
An Overview of Environmental and Health Issues
Recycling of asphalt shingles is still lagging behind social concerns resulting from a burgeoning world population. The Construction & Demolition Recycling Association says the greatest concerns are worker health and safety, and the impact on people living nearby.
Older asbestos shingles are still gradually finding their way through the system too. The Association closes its report with advice for companies involved in recycling shingles. They must expect to find asbestos, it says and be adequately prepared to deal with it.
Valiant Exteriors has procedures to remove old shingles carefully, and minimise impacts on customers, employees and surrounding properties. We do our utmost to ensure the spent materials enter a responsible recycling chain, and ensure you of our best service at all times. Why not give us a call on Calgary (403) 829-1661 now?
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Image Sourced from Dale Mahalko BY CC 3.0