Indicative strength class
The indicative (minimum) strength class of the concrete depends on the exposure class, that is defined in the table 4.1 of EN 1992-1-1. The indicative strength class is given in the table E.1N:
Exposure class | Indicative strength class |
X0 | C12/15 |
XC1 | C20/25 |
XC2 | C25/30 |
XC3 | C30/37 |
XC4 | C30/37 |
XD1 | C30/37 |
XD2 | C30/37 |
XD3 | C35/45 |
XS1 | C30/37 |
XS2 | C35/45 |
XS3 | C35/45 |
XF1 | C30/37 (C25/30) |
XF2 | C25/30 (aeration min.4%) |
XF3 | C30/37 (C25/30 aeration min.4%) |
XF4 | C30/37 (aeration min.4%) |
XA1 | C30/37 (C25/30) |
XA2 | C30/37 |
XA3 | C35/45 |
Note: values in brackets are valid for the Czech republic (table E1.CZ). The higher strength class shall be used for aeration lower than the minimum value.