Acoustic emission quantitative evaluation of rejuvenators to restore embrittlement temperatures to oxidized asphalt mixtures

- Acoustic emission approach allows to estimation of oxidative aging in asphalt mixtures.
- Rapid estimation of embrittlement temperatures of asphalt mixtures.
- Provides source location of thermal cracks in asphalt mixtures.
- Acoustic emission approach has potential to evaluate rejuvenator's efficiency.
- Approach is portable and easy to operate when compared to traditional methods.

An acoustic emission (AE) approach to evaluate the effectiveness of rejuvenators in restoring aged asphalt concrete to its low-temperature performance grade is presented. Specimens, oven-aged for 36 h at 135 °C, were treated with rejuvenators (10% of binder weight). After 2, 4, 6, and 8 weeks of dwell time, the specimens were tested using AE while being cooled down to −35 °C. It was observed that after four weeks of dwell time, the rejuvenated-treated specimens had recuperated the original embrittlement temperatures. After eight weeks, the specimens' embrittlement temperature were about three grades (∼18 °C) lower than those of the aged temperatures.