Estimating the potential strength of concrete with prior load history

Recommended procedures in evaluating the results of concrete core testing to establish the estimated in situ cube strength or estimated potential strength of concrete are given in standards and guidance documents. Many factors have been considered to determine their combined influence in the interpretation of the conversion process, from a core strength to an equivalent moulded cube strength. Nonetheless, it is recognized that further research is required to determine the effects of other influencing factors. This experimental investigation examines the effects of different degrees of simulated uniaxial compressive load history within prismatic concrete specimen on the strength of cores drilled in the direction of the load history from different locations of the specimen. The results show that the strength of a core drilled from such parent concrete may be as much as 31·7% lower than that of a similar size core drilled from similar parent concrete which has no prior load history.