We get the same two questions almost every week about the CSC Bostwick Consistometer:
1) What angle do I use to set it up?
2) How do I level the Consistometer?
The principle of the CSC Bostwick Consistometer is based on the slump cone. In this procedure, a cone is filled with the material to be tested. It is then set on a level surface with the open area facing downward. The cone is pulled away and after a fixed time, the amount that the material slumped is measured. The thicker the material, the less slumping occurs.
In the CSC Bostwick Consistometer, the area behind the closed gate is filled with the material to be tested. This cube of material is analogous to the material inside the cone. When the gate is released, it opens one side of the cube, allowing the material to flow down the trough – similar to the slumping action when the cone is lifted. The amount of analogous slump is measure by the distance the material flows in a given length of time.
To make this work consistently from test to test, the CSC Bostwick Consistometer needs to be perfectly level. This can usually be achieved using the circular level mounted on the Bostwick and adjusting the leveling screws. Occasionally the front of the Consistometer gets bent. In those cases the angle of the consistometer should be measured by placing a small level in the bottom to the trough.
To review, the answers to the questions raised at the beginning of this article:
1) The CSC Bostwick Consistometer should be level, not at any angle.
2) The Bostwick is leveled using the circular level on the front (adjusting the two leveling screws as needed) or with a level in the trough.
The consistency measurement is made by reading the number on the trough where the outermost edge of the sample has spread to at the pre-established time.
I hope that this has helped to clarify the set-up of the CSC Bostwick Consistometer.
Please share this with anyone you think would find it useful.
As always, a slightly disoriented,
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P.P.S. We have a video - "How to Run a Bostwick Consistometer Test"