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Group moderated by Mike Bergin and Celik Ozyildirim. Self-consolidating concrete (SCC) is highly flowable, nonsegregating concrete that can spread into place, fill the formwork, and encapsulate the reinforcement without mechanical consolidation. SCC has also been described as self-compacting concrete, self-placing concrete, and self-leveling concrete, which are subsets of SCC. SCC has high workability, as described in terms of filling ability, passing ability, and stability. The passing ability (confined flowability) refers to the ease with which concrete can pass among the various obstacles and narrow spacing in the formwork without blockage. The passing ability is measured by the J-ring, L-box, or U-box tests. The J-ring consists of a ring of reinforcing bar that fits around the base of a standard slump cone. The final spread of the concrete is measured, and the difference between the conventional slump flow value and the J-ring slump flow value is calculated. The L-box or the U-box contains reinforcing bars that divide the box into two compartments. A sample of fresh concrete is placed in one compartment, and the height of the concrete in the second compartment is measured after the gate between the two compartments is lifted. The J-ring test has been standardized as ASTM C 1621.
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