J-Ring Apparatus for Self Compacting Concrete
This test method is used for determining the passing ability (measured by the blocking step), the flow spread and flow time of the self compacting concrete as the concrete flows through the J-Ring. The J-Ring flow spread indicates the restricted deformability of SCC due to blocking effect of reinforcement bars and the flow time indicates the rate of deformation within a defined flow distance. The blocking step quantifies the effect of blocking. The apparatus consists of a stainless steel crown with 16 bars 18 mm dia.
The difference between the slump flow and J-Ring flow is an indication of the passing ability of the concrete. The test method is applicable for laboratory use in comparing the passing ability of different concrete mixture. It is also applicable in the field as a quality control test. It can also be used to investigate the resistance of SCC to segregation by comparing test results from two different portions of sample