Effects of Specimen Preparation on the Properties of Fresh and Hardened High Fluidity Concretes

A new method is proposed for the preparation of specimens of high fluidity concrete with excellent flowability and segregation resistance that can not be fully controlled by the current Japanese Industrial Standard. Procedures recommended are: (1) Slump cone should be filled in three equally divided volumes followed by rodding of 5 strokes at each layer; (2) Flow time recommended for quality control should be in 5 to 10 seconds; and (3) Cylinder mold phi 10 x 20 cm for the compressive strength test should be filled in two equally divided volumes followed by a rodding of five strokes at each layer, considering coarse aggregate content and stability of mechanical properties.