What is the maximum allowed percentage of extraneous material for recycled asphalt shingles (RAS) in material retained above the No. 4 sieve?

• A. 0.5 percent
• B. 1.5 percent
• C. 2.0 percent
• D. 5.0 percent

Answer: (B)

Understanding how clean recycled asphalt shingles must be when used in the larger, retained fraction is the key here. Extraneous material refers to non-shingle debris like dirt, paper, or other debris mixed in with the shingles. For the portion of RAS that remains on the No. 4 sieve, the maximum allowed extraneous material is 1.5 percent. Keeping within this limit helps maintain consistent asphalt content and the performance characteristics of the final mix, because too much non-shingle material can skew binder content and grading. If the extraneous material exceeded this limit, it would indicate the RAS isn’t clean enough for acceptable quality, while this 1.5 percent cap represents a practical balance between ease of obtaining material and maintaining performance.