ABSTRACT
The purpose of quality control (QC) is to ensure the continuous production of an item of the required quality at minimum cost. Many countries still attempt to do this for concrete by testing specimens at an age of 28 days and provisionally rejecting concrete that does not comply. It is rarely feasible to actually discard concrete that has been in place for 28 days so further testing by drilling cores or by ultrasonic testing ensues. Also the concrete in trucks not sampled for testing remains under suspicion.
