Flow table test
These images show a flow test with very fluid concrete for a special application which made compression impossible.
The flow table test or flow test is a method to determine the consistence of fresh concrete.
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.
During the test the site engineer should be present.
Equipment
- Flow table with a grip and a hinge, 70 cm x 70 cm.
- Upside down funnel which is open at the top and at the bottom - 12cm high, 17 cm top diameter, 25cm base diameter.
- Water bucket and broom for wetting the flow table.
- Tamping rod.(60 cm height)
Conducting the test
- The flowtable is wetted.
- The upside down funnel is placed on the flowtable and filled with fresh concrete.in two layer each layer 25 times tamp with tamping rod.
- The funnel is lifted up, allowing the concrete to flow.
- The flowtable is then lifted up several centimeters and then dropped, causing the concrete flow a little bit further.
- After this the diameter of the concrete is measured. The result is called "Ausbreitmaß" in German.
- flow table fill with wet concrete
See also
Links and Sources
- DIN EN 12350-5
- b-i-m (German)
- Heidelberg Cement (German)
- Concrete Flow Table in an online shop