The slump-flow and t500 time is a test to assess the flowability and the flow rate of self compacting concrete in the absence of obstructions. It is based on the slump test described in EN 12350-2.
The result is an indication of the filling ability of self compacting concrete. The t500 time is also a measure of the speed of flow and an indication of the viscosity of the self-compacting concrete.
The fresh concrete is poured into a cone as used for the EN 12350-2 slump test. When the cone is withdrawn upwards the time from commencing upward movement of the cone to when the concrete has flowed to a diameter of 500 mm is measured; this is the t500 time. The largest diameter of the flow spread of the concrete and the diameter of the spread at right angles to it are then measured and the mean is the slump-flow.