Comparative analysis on the relevant probability distribution model for the compressive strength of concrete taking into account the size dependence

Abstract

This paper presents a comparative investigation on the size effect of the probability distribution of the compressive strength of concrete by using three common probability functions, including normal, log-normal, and Weibull distributions, was carried out on a set of 240 measured strength values. These strength datasets were derived from a comprehensive set of compression tests conducted on numerous concrete specimens of four distinct cylindrical sizes, which were prepared using two different concrete mix proportions. From this analysis, it is demonstrated that: (i) irrespective of the mix proportion, size, and type of the concrete specimen, the normal distribution offers the most relevant model for interpreting not only the probability distribution of the compressive strength of concrete but also its size dependence; (ii) the size effect on the compressive strength of concrete results in its probability distribution also being affected by the sample size; and (iii) the size effect on the probability distribution of concrete compressive strength can be interpreted through the normal and log-normal distributions, but not through the Weibull distribution.