PG 76-22 & PG 82-22
The Performance Grade Modified Bitumen are based on two factors: traffic and pavement temperature. Adjustments are made to the PG grade of bitumen based on traffic conditions and traffic volumes which are intended to enhance the design life of the pavement. The PG grading system is defined by two numbers, which represent pavement temperatures.
The first number PG represents the high pavement temperature in degrees Celsius, while the second number PG represents the low pavement temperature in degrees Celsius. Notice that these numbers are pavement temperatures and not air temperatures. The high temperature relates to the effects of rutting and the low temperature relates to cold temperature and fatigue cracking.