# Mean value of concrete compressive strength at an age of `t` days, `f`_{cm}(t)

_{cm}(t)

## Eurocode 2 part 1-1: Design of concrete structures 3.1.2 (6)

The compressive strength of concrete at various ages, `f _{cm}`(

`t`), may be estimated as follows:

f(_{cm}t) = β(_{cc}t)⋅f _{cm} | (3.1) |

where:

`f`_{cm}- is the mean compressive strength 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).

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