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Concrete strength at an age of t days

Mean compressive strength of concrete at an age other than 28 days for cement class N. Reference: EN 1992-1-1 3.1.2(6), expressions 3.1-3.2.

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Concrete strength at an age of t days: worked example sheet in Equation Pad with typeset equations and results.

Example only. This sheet shows one way to set out the check. It is not endorsed by the bodies that publish the design codes and does not reproduce them. Check every clause, value and assumption against your own copy of the current edition of Eurocode 2 and its national annex before you use it, and have the result checked by a competent person. See the disclaimer.

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# Inputs
f_ck := 30 MPa
t := 7
s := 0.25
# s = 0.20 for cement class R, 0.25 for N, 0.38 for S.

# Strength
f_cm := f_ck + 8 MPa =
beta_cc := exp(s*(1 - sqrt(28/t))) =
f_cmt := beta_cc*f_cm =
f_ckt := f_cmt - 8 MPa =

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