Evaluation of compound compliance criteria for concrete strength

Abstract

In the compliance control of concrete, different types of criterion are in use. In particular, compound criteria are often used since this type of criterion appears in the CEB-FIP Model Code for Concrete Structures. In this paper, the dependency between the minimumvalue and the mean-value criteria is shown not to be negligible. The usefulness of a minimum-value criterion is questioned, as generally it unnecessarily decreases the probability of acceptance for low defective fractions. The preliminary application of an outlier criterion is suggested as a more consistent approach. Finally, criteria of the type$\bar x_n \geqslant f_{ck} + \lambda s_n$ are proposed, where the numerical values of λ are fixed in such a way that the resulting OC lines are tangent to a continuous boundary line for the unsafe region.