What is characteristic strength of concrete in flexure ?

Blog By Er. Navneet Kumar

What is characteristic strength of concrete in flexure ?

 👉Characteristic strength of concrete is the value of strength of concrete below which not more than 

5 % of test results are expected to fail. 

           It is denoted by fck.

                                                          fck = fm- 1.65σ

       Where fm= Target mean strength & σ = standard deviation.

Note-

👉Concrete is designated by characteristic cube strength of concrete at 28 days.

👉No material is truly homogeneous , so strength of similar concrete varies in different testing.

👉For most of the engineering materials ,probability is symmetrical about mean and such a curve is called Normal Probability distribution curve.