A unique feature of the Superpave System is that the specifications are performance-based. PG asphalt binders are selected to meet expected high- and low- temperature extremes with a certain level of reliability.
Example of a PG asphalt binder
PG 64-28: the first number (64) indicates that the binder meets high-temperature physical properties up to 64 degrees Celsius. The last number (-28) indicate the binder meets low-temperature physical properties down to -28 degrees Celsius.