If a concrete specimen is tested to failure in compression and the machine allows the
longitudinal strain in the specimen to be non-uniform over the cross-section of the specimen
at its maximum load, then that load is lower than it would be if the strains were uniform. The
results of an experimental study on the magnitude of the effect of non-uniform straining on
apparent concrete strength are presented, showing how it varies for low, medium, and high
strength concrete. Simple theoretical modeling is shown to reproduce the measured results …