Flow table test is used to calculate the workability of concrete. In the flow table test workability of concrete is determined by observing the flowing property of concrete. It is a lab test that suits low concrete workability.
This test was also used to determine consistency, cohesiveness, and the proneness to segregation.
Workability is a very complex characteristic of concrete that directly impacts Concrete strength, quality, and appearance and it also determines how easily freshly made concrete can be mixed, placed, compacted, and finished with the minimum to no loss concerning homogeneity.
As mentioned, it’s a complex property that involves many factors concerning good workable concrete. To test the freshly mixed concrete workability, the flow table test of concrete is usually performed on the field and lab.
Table of Contents
Flow Table Test Apparatus:
- Flow table
- tamping rod
- Scoop
- Scale
- Metal Cone
The complete arrangement of the flow table is shown in the below figure.
Procedure:
- First, make the concrete as per the mix design and place the flow table on a horizontal surface.
- Clean the dust from the water table and sprinkle some water on it.
- Now, set the cone at the middle part of the flow table and stand on it.
- Pour the freshly mixed concrete into the metal cone comprising two layers; each layer should be tamped with a tamping rod for 25times. After tamping the final layer, the overflowed concrete on the cone is struck off using a trowel.
- Gradually lift the cone vertically up and let concrete stand on its own without any support.
- The flow table is raised at a height of 12.5 millimetres and dropped. The same is repeated 15 times in 15 seconds.
- Measure the spread of concrete in Diameter utilizing centimetre scale horizontally and vertically. The arithmetic mean of the two diameters shall be the measurement of flow in millimetres.
The following formula is used to calculate the flow value of concrete.
Flow Value Of Concrete = (D1+D2)/2
Check out the video of the flow table test for better visualization.
Video Credit: اعداد مهندس مدنياعداد مهندس مدني
Faqs
The flow table test of concrete is a way to check how easily the concrete can move and spread. It helps us know if the concrete is easy to work with.
We do the flow table test to see if the concrete is good to use. It tells us if the concrete can be poured and shaped easily.
To do the flow table test, we put the concrete on a flat table and then lift the table up and drop it down a few times. Then we measure how much the concrete spreads out.
The flow value tells us how well the concrete flows. If the flow value is high, it means the concrete is very fluid and easy to work with. If the flow value is low, it means the concrete is stiff and not easy to move.
Yes, there are some limits to the flow table test. It only tells us about how the concrete flows, but it doesn’t tell us about other important things like how strong the concrete is or how long it takes to harden. So we use other tests along with the flow table test to learn more about the concrete.