In-place compressive strength of concrete: statistical methods to evaluate experimental data

This paper describes a number of statistical methods to estimate, through an analysis of in-place test results, the in-place compressive strength of concrete expressed as strength of standard specimens. The evaluation of the probable existence of a linear correlation as a function of sample size is discussed. The regression laws and the degree of reliability of the estimates obtained is also discussed. A criterion is proposed for the choice of the number of points to be used in the regression. Finally a method is proposed, knowing the numberm of replicated in-place tests, to estimate the equivalent numbern of replicated tests performed on standard specimens.