In PG bitumens, classification is done based on understanding the behavior of bitumen and its performance characteristics, so that in this classification, different characteristics against cracking and deformation due to cold and heat and fatigue are taken into account and the prediction of hardening of bitumen at the production site and factory during asphalt preparation. Also, the amount of traffic and the passage of time and the speed of loading on the road are taken into account.
PG bitumens are graded based on performance at different temperatures, so that the highest and lowest asphalt temperatures are previously calculated and the best bitumen at that operating temperature is suggested.
| High Temperature Performance of PG | Low Temperature Performance of PG |
| PG 46 | -34,-40,-46 |
| PG 52 | -10,-16,-22,-28,-34,-40,-46 |
| PG 58 | -10,-16,-22,-28,-34,-40 |
| PG 64 | -10,-16,-22,-28,-34,-40 |
| PG 70 | -10,-16,-22,-28,-34,-40 |
| PG 76 | -10,-16,-22,-28,-34 |
| PG 82 | -10,-16,-22,-28,-34 |