# Mean value of axial tensile strength of concrete at an age of `t` days, `f`_{ctm}(`t`)

_{ctm}

## Eurocode 2 part 1-1: Design of concrete structures 3.1.2 (9)

The mean value of axial tensile strength of concrete an age of `t` days is:

f(_{ctm}t) = (β(_{cc}t))^{α}⋅f _{ctm} | (3.4) |

where:

`f`_{ctm}- is the mean value of axial tensile strength of concrete at 28 days, see Table 3.1
`β`(_{cc}`t`)- is a coefficient which depends on the age of the concrete
`t`:`β`(_{cc}`t`) = exp {`s`[1 - (28/`t`)^{1/2}] }(3.2) with

`t`- the age of the concrete
`s`- a coefficient which depends on the type of cement:

= 0,20 for CEM 42,5 R, CEM 52,5 N and CEM 52,5 R (Class R)

= 0,25 for CEM 32,5 R and CEM 42,5 N (Class N)

= 0,38 for CEM 32,5 N (Class S).

`α`- = 1 for
`t`< 28 days

= 2/3 for`t`≥ 28 days.

This application calculates
the mean tensile strength `f _{ctm}(t)`
from your inputs.
Intermediate results will also be given.