Recycled Asphalt Shingles

Executive Summary 

Asphalt shingles are the most prevalent roofing material in the United States. After their lifespan of 10–30 years, asphalt shingles require replacement, and the old material becomes waste that is either diverted to landfills or recycled into post-consumer products used in the building industry. Asphalt shingles can be ground into granular particles for utilization as base layers or additives for roadway pavements. The incorporation of recycled asphalt shingles (RAS) into pavement can decrease the cost of roadway construction, but only a fraction of total asphalt shingle waste is recycled. The processing, storage, and implementation of recycled asphalt shingles have raised concerns of emissions of dangerous airborne particles and leaching of chemicals into soil and water. Several states, including Missouri, utilize pavements that incorporate recycled asphalt shingles. Proposed during the 2022 Missouri legislative session, HB 2447, HB 2485, and SB 984 seek to allow processed recycled asphalt shingles to be used for structural fills, reclamation, or other beneficial purposes. Processed recycled asphalt shingles would also be considered as clean fill. 

Highlights 

• In the United States, approximately 13 million tons of asphalt shingle waste is sent to landfills annually.
  • In Missouri, roughly 146,500 tons of asphalt shingles are discarded annually.

• Recycling asphalt shingles reduces the need to extract raw natural resources (e.g., petroleum)  and minimizes the amount of waste sent to landfills.

• The incorporation of RAS can increase pavement durability and reduce cracking and ruts, but research assessing performance is variable and inconsistent. 

• Health concerns cited from recycling asphalt shingles include possible exposure to asbestos, secondary organic aerosols, and petroleum-based chemicals called polycyclic aromatic hydrocarbons (PAHs).
  • Research suggests that PAHs do not readily leach from asphalt products. 

Limitations 

• Investigations of the site-specific environmental and health impacts of recycled asphalt processing are limited.

• There is a lack of research regarding both the performance and market demand of recycled asphalt shingles for structural fill.