U-Box test, funnel test and J-ring test are some of the other examples of test for determining the workability or fluidity of the self-compacting concrete. Each different test attempts to look into different aspects of the self-compacting concrete namely; filling capacity, passing ability and segregation resistance.
In the U box test difference in the height of concrete in the two legs of a standard U tube is taken as a measure of the workability of concrete. As it uses an obstacle in the form of equally spaced bars between the two legs, it essentially mimics the flow through congested reinforcement arrangement and measures the passing ability SCC (see Fig. 3a)). In the funnel test, time taken to empty the funnel is taken as a measurement for the workability of the concrete mix (see Fig. 3b)). Funnel test looked at the segregation
resistance of the SCC mix. Similar to the U box test, L box test also employs an obstacle and measures the passing ability of SCC and uses the ratio of the concrete height in the horizontal leg as indication of the workability of the mix (see Fig. 3c)). Professional bodies like JSCE (JSCE 2005) have come forward to recognize such testing procedures and standardize the same so that they can be adopted universally to
compare self-compacting concrete.