Correspondence mark concrete class
| Concrete mark | Concrete class (C140-86) | Concrete class (NE 012-99) | Cylinder compressive strength (Fck [N/mm2]) | Cube compressive strength (Fck [N/mm2]) |
| B50 | Bc 3.5 | C 2.8/3.5 | 2.8 | 3.5 |
| B75 | Bc 5 | C 4/5 | 4 | 5 |
| B100 | Bc 7.5 | C 6/7.5 | 6 | 7.5 |
| B150 | Bc 10 | C 8/10 | 8 | 10 |
| B200 | Bc 15 | C12/15 | 12 | 15 |
| B250 | Bc 20 | C 16/20 | 16 | 20 |
| B300 | Bc 22.5 | C 18/22.5 | 18 | 22.5 |
| B330 | Bc 25 | C 20/25 | 20 | 25 |
| B400 | Bc 30 | C 25/30 | 25 | 30 |
| B450 | Bc 35 | C 28/35 | 28 | 35 |
| – | – | C 30/37 | 30 | 37 |
| – | – | C 35/45 | 35 | 45 |
| B500 | Bc 40 | C 32/40 | 32 | 40 |
| B600 | Bc 50 | C 40/50 | 40 | 50 |
| – | – | C 45/55 | 45 | 55 |
| B700 | Bc 60 | C 50/60 | 50 | 60 |
