V-funnel (Alternative method to T50 for filling ability)
The V-funnel flow time is the period a defined volume of SCC needs to pass a narrow opening and gives an indication of the filling ability of SCC provided that blocking and/or segregation do not take place; the flow time of the V-funnel test is to some degree related to the plastic viscosity.
· V-funnel, as shown in Figure 6, made of steel, with a flat, horizontal top and placed on vertical supports, and with a momentary releasable, watertight opening gate.
· Stopwatch with the accuracy of 0.1 second for recording the flow time.
· Straightedge for leveling the concrete.
· Buckets with a capacity of 12∼14 litres for taking concrete sample.
· Moist sponge or towel for wetting the inner surface of the V-funnel.
· Place the cleaned V-funnel vertically on a stable and flat ground, with the top opening horizontally positioned.
· Wet the interior of the funnel with the moist sponge or towel and remove the surplus of water, e.g. through the opening. The inner side of the funnel should be ‘just wet’.
· Close the gate and place a bucket under it in order to retain the concrete to be passed.
· Fill the funnel completely with a representative sample of SCC without applying any compaction or rodding.
· Remove any surplus of concrete from the top of the funnel using the straightedge.
· Open the gate after a waiting period of (10 ± 2) seconds. Start the stopwatch at the same moment the gate opens.
· Look inside the funnel and stop the time at the moment when clear space is visible through the opening of the funnel. The stopwatch reading is recorded as the V-funnel flow time, noted as tV. NOTE Dot not touch or move the V-funnel until it is empty.
· Clean the V-funnel after testing.
Expression of results
The V-funnel flow time tV is the period from releasing the gate until first light enters the opening, expressed to the nearest 0.1 second.