The influence of size of concrete test cubes on me all strength and standard deviation Available to Purchase

It is suggested that the mean strength and the standard deviation of a sample of concrete cubes are functions of the cube size. The results of tests on over 300 cubes of three sizes are given, and from the statistical analysis of these results it is concluded that the smaller 2·78 in. cubes have a significantly higher mean strength and higher standard deviation than the larger 5 in. and 6 in. cubes.

From these results, it is suggested that the standard deviation obtained from standard 2·78 in. mortar cubes gives an excessive estimate of the effect of the variation in cement quality as compared with the results obtained from 6 in. or 4 ill. concrete cubes.