Hope you know self-compacting concrete, which does not need any external force to settle properly over the structure.
What is the Flow Table Test?
The Self-compacting concrete used where the reinforcement is congested and concrete compaction not possible by vibrator.
The test used to find out the fluidity of freshly mixed self-compacting concrete is known as Flow Table Test. It is conducted in the laboratory.
There are some other tests which is used to find out the consistency based on their workability
The ability of concrete to handle, transport, and placing between the formwork with minor segregation is called the Workability of concrete.
|SI||Test Name||Suitable Workability||Field/Lab|
|2||Kelly Ball Test||High||Field/Lab|
|4||Flow Table test||Low||Lab|
|5||Vee – bee test||Low & very low||Lab|
Principles of Flow Table Test
The flow table test is performed in the lab to find out the fluidity of concrete where the nominal size of the coarse aggregates does not exceed 38mm.
The flow table test will be performed as per BS EN 12350 part 1 standards.
How to take a sample for this test?
The sample volume of concrete should not be less than 0.02cum of the concrete batch. If the concrete contains an aggregate size of more than 38mm, then it should be a wet screen to exclude the bigger size aggregates.
The sample concrete should be taken immediately from a batch of concrete, which is before to pour over the formwork.
- 700 X 700 mm dia flow table
- 200 mm high metal mould with 200 mm dia bottom & 130 mm dia top
- Tamping wood
- Waste cloth / Sponge to clean
- Measurement scale
Flow Table Test Procedure
- The flow table must be placed in such a way that the external vibrations won’t affect the process.
- The table & mould should be free from water and dust.
- The mould should be placed on the center mark to the table.
- The sample concrete should be filled in the cone mould by two layers, and each layer should be tamped 10 times by the tamping wood.
- Once the mould has filled, then remove the excess concrete by trowel and level the top surface.
- Then remove the mould in a vertical direction and let the concrete spread.
- Now raise the flow table at 40 mm height (limited by the tabletop) and drop it 15 times in about 30 seconds.
- Finally, measure the spread concrete in 2 right angle directions and record value.
The flow percentage of concrete is the percentage of spread concrete average diameter increment over the base diameter of moulded concrete.
Acquire the result using the below flow table test formula
Video Courtesy – اعداد مهندس مدني