Microcores (very small diameter) of hardened concrete. Are they representative?

Abstract

The variables that mainly influence the results obtained in the compression tests of concrete cores of conventional diameters are well established and amply investigated. This is not the case, neverthless, of the microcores or cores of very small diameter, because is not well known the level of accuracy that we can achieve in the in situ estimation of concrete strength, by testing this samples obtained from the structure. In this paper, are presented the results obtained in an experimental research, realized in order to bring some additional information about the behaviour and level of representativity of microcores of concrete placed in a real structure and, also, concretes used in structural beams manufactured in factory (normal or prestressed beams).