Postconsumer shingles have relatively higher binder stiffness due to aging.

• A. True
• B. False
• C. Not Applicable
• D. Not Sure

Answer: (A)

Aging of asphalt binder makes it stiffer because exposure to heat, oxygen, and sunlight causes oxidation and loss of lighter fractions. In roofs, the binder in asphalt shingles ages for years, so the binder becomes harder and more brittle. When you reclaim postconsumer shingles, that aged, stiffer binder is brought back into the mix, making the overall binder stiffer than fresh material. That’s why the statement is true: aging has already increased stiffness in the shingles’ binder, and this characteristic carries into reclaimed materials used in pavement. In practice, this stiffer aged binder can improve rutting resistance at high temperatures but may reduce low-temperature flexibility unless rejuvenated or blended appropriately.