The American Society of Concrete Contractors, of Saint Louis, Missouri, has published a Technical Checklist for Concrete Core Testing to ensure that drilled cores are obtained and tested properly. The checklist was compiled to help concrete contractors and producers confirm that core strengths represent the true condition of the in-place concrete. Items in the checklist are based on ASTM C 42-04, “Standard Test Method for Obtaining and Testing Drilled Cores and Sawed Beams of Concrete.” The list covers sampling, specimens, measurement, testing, and reporting.
Strength testing that indicates low results require that steps be taken to assure that the load-carrying capacity of a structure is not reduced. If the likelihood of low-strength concrete is confirmed, and calculations indicate that load-carrying capacity is significantly reduced, core tests may be required. Core tests can be problematic, incorrectly indicating low core strength, if they are not performed, stored and tested accurately.