For many years, post-manufactured and post-consumer asphalt shingle waste was successfully recycled into asphalt paving, providing both a sustainable and cost-effective alternative to landfill disposal. At one time, asphalt paving companies even paid for post-manufacturing waste due to the value of the unaged asphalt.

As paving regulations evolved to become more sustainable, the industry prioritized the use of Recycled Asphalt Pavement (RAP), a proven and essential component in modern asphalt mix design. While RAP plays a critical role in sustainable paving, this shift has significantly reduced demand for Recycled Asphalt Shingles (RAS).  The post-manufactured waste may still have options in paving due to the value of the unaged asphalt, but the roof tear-off shingles that are a large majority of the RAS will be used less in paving.  At the same time, landfill restrictions on asphalt shingles continue to expand, creating additional pressure to find viable recycling solutions.

To ensure long-term sustainability, the industry must explore new ways to integrate RAS into both paving and roofing applications—maximizing its value across multiple sectors.

The Need for Industry Collaboration
Prior to joining Polyco, I worked in the asphalt shingle market for Elk and GAF for almost 23 years. This experience taught me that it’s crucial for manufacturers to collaborate in updating industry codes to expand opportunities for shingle recycling. If immediate and deliberate changes are not made, the ability to use asphalt shingles in the future could become problematic due to end-of-life limitations.

The Importance of Updating Industry Codes
It is clear that significant and rapid gains must be made in the use of RAS in the production of new asphalt shingles. However, this opportunity has its challenges. 

There are two codes that provide criteria for evaluating asphalt shingle products. ASTM D3462 has been in place for many years and “is somewhat prescriptive and contains multiple weight measure requirements, which tends to limit future asphalt shingle innovation and product development.” In contrast, AC438, published in March 2012, “is largely testing- and performance-based with minimal prescriptive, weight and measure requirements.”  

Despite the apparent advantage of adhering to AC438, the industry continues to give greater credence and weight to the ASTM D3462 code. To advance the asphalt shingle industry, we must phase out ASTM D3462, expand support for AC 438, and develop additional codes that allow for even more flexibility and creativity in asphalt shingle design—paving the way for increased use of recycled materials.

Processing Challenges for Recycled Asphalt Shingles
Depending on the method used to process RAS, separating and concentrating the shingle raw material components can lead to mass and/or energy balance challenges. Mechanical methods can remove most of the large headlap and butt (colored) granules, which can then be reused as headlap granules in new shingles. This is the easiest part of the process, with minimal impact on new shingle production, as long as any asphalt remaining on the recycled granules does not cause clumping in storage silos or interfere with application equipment. 

The major challenge is separating the asphalt from the filler, fines, and fiberglass mat. Whether the process is solvent-based liquid, mechanical pulverization, or a combination of both, remnants of these raw materials will contribute to the total filler content of the new shingles. This can be detrimental to the shingle’s performance properties—such as tear strength—as the preferred filler is substituted by these other materials.

Overcoming Regulatory and Material Limitations
The prescriptive requirements of ASTM D3462 will quickly limit the amount of recycled shingle material because of filler limitations in the finished shingle. The issue of higher filler could possibly be overcome with asphalt improvements or additives, but this is not even an option if roofing stays focused on ASTM D3462.

Polyco has demonstrated that SigmaBond, an advanced asphalt rejuvenator, can help offset the effects of aged asphalt in post-consumer RAS while also addressing higher filler content. SigmaBond incorporates liquefied tire rubber, which enhances the durability and flexibility of asphalt, making it a valuable solution for increasing the use of recycled materials in roofing applications. However, ASTM D3462 remains a barrier, as its prescriptive requirements restrict certain components—such as carbon black and other non-asphaltic materials found in ground tires—limiting the full potential of innovative recycling solutions.  

The quotes above are from an article by Mark S. Graham, NRCA’s Associate Executive Director of Technical Services, in Tech Today, July 2013, Alternative asphalt shingle products.