AASHTO TP 122-16 (2020) PDF Download

AASHTO TP 122-16 (2020) is a provision standard method for determining the performance grade of physically aged asphalt binder using the extended bending beam rheometer (BBR) method. The purpose of this standard is to establish the minimum design pavement temperature at which the asphalt binder remains capable of performing under low-temperature conditions.

The method involves subjecting the asphalt binder to a physical aging process, which involves hardening the binder by aging it at specific temperatures and durations. The bending beam rheometer is then used to test the flexural stiffness of the aged binder within the temperature range of -36 to 0°C. The test is conducted at temperatures 10°C higher than the low-temperature performance grade to determine if the binder meets the low-temperature requirements.

This standard specifies that the physical aging process should be carried out at two different temperatures, 10°C and 20°C higher than the low-temperature performance grade, for durations of 1 hour, 24 hours, and 72 hours. By evaluating the flexural stiffness of the aged binder at different temperatures, the method allows for determination of the limiting temperature at each conditioning time.

It should be noted that the test results are considered invalid if the deflection of the asphalt binder during testing exceeds 4 mm or falls below 0.08 mm according to this method.