Shingles — a green idea

As the benefits of recycling gain momentum in the paving industry, asphalt producers/contractors and their road agency customers continue to explore the possibilities of increasing the use of reclaimed asphalt pavements (RAP) as a cost-effective solution for building and maintaining this nation’s road infrastructure. It not only makes sense economically with the ever-increasing cost of fuel and construction materials, but it also makes sense environmentally by reducing the demand on natural resources and landfill space.

That’s why it also makes sense to recycle asphalt shingles, whether they’re new manufacturer rejects or old tear-offs. The resource value shingles provide is similar to that of RAP - aggregate, AC and fiber.

There are some DOTs that have taken a progressive approach in specifying projects that allow mix designs with RAP and added shingle content. Minnesota asphalt producer/contractor Bituminous Roadways (see story on page 22) has spent the past 10 years promoting, producing and placing hot mix asphalt containing shingle content on MnDOT projects, and it’s been a collaborative effort on the part of both. It started out as small test projects and eventually evolved into full-blown state highway contracts that now clearly define content and performance specifications.

Other contractors and state agencies are also working toward increased recycling efforts that maximize investments while still delivering a quality pavement. The HMA industry has the knowledge, equipment and talent to deliver cost-effective quality pavements with high RAP content. Asphalt producers/contractors can process RAP in a way that separates it into the various components required to produce a mix, and in doing so, they can design mixes with the same high-performance characteristics achieved when using virgin materials. They can also do the same to incorporate a small percentage of recycled waste shingles.

For road agencies the bottom line on allowing RAP or recycled shingles to be used in a mix design is clear - deliver a pavement that performs as well as one produced with only virgin materials. In the case of Bituminous Roadways’ most recent project, the asphalt producer/contractor did just that and received smoothness and density bonuses in the process, while saving the road agency customer an additional $100,000 over and above the savings generated by using RAP simply by allowing recycled shingles to be used on the project.

Recycling simply makes sense. Why landfill valuable resources when they can be used to construct a quality pavement? For the paving industry, the customers it serves and taxpayers who ultimately pay the bill, recycling asphalt pavements and asphalt shingles will not only save money and landfill space today, but it will also sustain the resources needed to build and maintain a quality road infrastructure in the future.

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