Assessing the quality control of self-consolidating concrete properties

The results of a quality-control operation performed on the jobsite of a large volume of ready-mix self-consolidating concrete (SCC) are presented. To test the prerequisites of fresh SCC, three tests (slump flow [SF], V-Funnel [VF], and J-Ring [JR]) were prescribed to be performed on every truck. The acceptance condition for the supplied concrete was to meet the specified requirements for all three tests. This procedure seems adequate to derive reliable data about filling ability, resistance to segregation, deformation capacity, viscosity, and passing ability. The correlation between slump-flow and J-ring results suggests that these two tests could be associated by defining a proper reduced J-ring diameter and by checking the difference in height between the concrete inside and outside the ring. In general, it seems that a continuous control should be applied only on specific structures, such as structures with highly congested reinforcement, whereas when the stability of the supplies is achieved, a reduced testing control could be applied for ordinary structures. However, whatever the type of construction, in extreme weather conditions (very hot/cold) special care should be taken, and it could be necessary to increase the number of controls because under these conditions a higher probability of nonconformance to the guidelines was observed.