Vee Bee Consistometer Test for Workability of concrete

Vee Bee Consistometer Test

 It is based on measuring the time (Called VEE BEE time) needed to change the shape of a concrete mix from a frustum cone to a cylinder (these shapes are standardized by the apparatus of this test), by vibrating and compacting the mix. The more VEE BEE time needed the less workable the mix is. This method is mostly useful for measuring workability of stiff mixes.

 Apparatus

  Cylindrical container with diameter = 240 mm, and height = 200 mm
Mold: the same mold used in the slump test.
Disc : A transparent horizontal disc attached to a rod which slides vertically
Vibrating Table : 380x260 mm, supported by four rubber shock absorbers
Tamping Rod ,Stop watch  for measuringVee Bee Time.

Vee Bee Consistometer

  Procedure

1.  Place the slump cone inside the sheet metal cylindrical pot of the consistometer. Pour the concrete inside the cone and tamp it properly.
2. The glass disc attached to the swivel arm is turned and placed on the top of the concrete in the pot.
3. The electrical vibrator is then switched on and simultaneously a stopwatch started.
4. The vibration is continued till such time as the conical shape of the concrete changes in to the  cylindrical shape.
5. This can be judged by observing the glass disc from the top disappearance of transparency. 
6. Immediately when the concrete fully assume a cylindrical shape, the stopwatch is switched off.
7. The time required for the shape of concrete to change from slump cone shape to cylindrical shape in second is known as Vee Bee time.
8. This method is very suitable for very dry concrete whose slump value cannot be measure by slump test.

  Note

The test fails if Vee Bee Time is less than 5 seconds.For this flow test may be used.

Workability vs Vee Bee time