Flow table test
The flow table test or flow test is a method to determine the consistence of fresh concrete. There is also another flow table test used to determine the Transportable Moisture Limit of solid bulk cargoes which are considered to be potentially liquefiable.[1]
Application When fresh concrete is delivered to a site by a truck mixer it is sometimes necessary to check its consistence before pouring it into formwork.
If the consistence is not correct, the concrete will not have the desired qualities once it has set, particularly the desired strength. If the concrete is too pasty, it may result in cavities within the concrete which leads to corrosion of the rebar, eventually leading to the formation of cracks (as the rebar expands as it corrodes) which will accelerate the whole process, rather like insufficient concrete cover. Cavities will also lower the stress the concrete is able to support.
Equipment
- Flow table with a grip and a hinge, 70 centimetres (28 in) square.
- Abrams cone, open at the top and at the bottom - 30 centimetres (12 in) high, 17 centimetres (6.7 in) top diameter, 25 centimetres (9.8 in) base diameter.
- Water bucket and broom for wetting the flow table.
- Tamping rod, 60 centimetres (24 in) long
Conducting the test
- The flow table is wetted.
- The cone is placed in the center of the flow table and filled with fresh concrete in two equal layers. Each layer is tamped 10 times with a tamping rod.
Wait 30 seconds before lifting the cone
- The cone is lifted, allowing the concrete to flow.
- The flow table is then lifted up 40mm and then dropped 15 times, causing the concrete to flow
- After this the diameter of the concrete is measured.
See also
Links and Sources
- DIN EN 12350-5
- b-i-m (German)
- Heidelberg Cement (German)
- Concrete Flow Table in an online shop