Aggregate Gradings for Nuclear Concrete

Abstract

Evaluation of concrete shows that segregation, inherent in rehandling of coarse aggregate, is significantly reduced in the large mixers used in concrete production. The investigation also shows that relatively broad ranges in coarse aggregate gradation as shown by the on site test data had no measureable effect on the strength of the inplace concrete. On nuclear work the dependence on data resulting from single increment samples taken from rehandled material results in misleading information as to the actual gradation of the material in use. Application of statistical techniques used to evaluate data received from the aggregate manufacturer, from the rehandled material, and the freshly mixed concrete yields reliable information by which product control can be established and maintained.