EVALUATION OF SMALL DIAMETER CORE TESTS TO DETERMINE IN SITU STRENGTH OF CONCRETE.

This paper presents tests on 50mm diameter cores to evaluate their use to determine in-situ concrete strength. The cores, with height to diameter ratios of 1 and 2, were drilled vertically from slabs which were cured in an uncontrolled internal environment to simulate conditions in practice. The variables investigated include concrete strength level, mix proportions, age, size and type of dense coarse aggregate and type of concrete, i. e. normal and lightweight. The core strength results are analysed to discuss the height to diameter correction factor and the relation between core strength and cube strength. The core strength results are related to core and cube pulse velocity and Windsor probe test results.