The design of structural elements is done by taking into account the characteristic strength of concrete and steel. Section dimensions, material strength, and stresses due to the applied loadings are considered for the design of the structural elements.
According to BS 5328 Part 1, the following definition is given for the characteristic strength.
That value of strength below which 5% of the population of all possible strength measurements of the specified concrete are expected to fall.
The strength that falls 5% of test results below that amount is called the characteristic strength. In other words, 95% of the test results are having the strength more than the characteristic strength. Figure 01 Indicates the probability chart that used to obtain the strength of the concrete.
Figure 01 Characteristic Strength of Concrete
Testing of concrete is done to verify whether the concrete has achieved strength during the construction. Further, the method of testing and sampling procedure will be discussed in a different article.