Normal Consistency of Cement - IS : 4031(Part 4)

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Scope

This standard ( IS : 4031 Part 4 ) covers the procedure for determining the quantity of water required to produce a cement paste of standard consistency.

Defination of Standard Consistency

The standard consistency of a cement paste is defined as that consistency which will permit the Vicat plunger to penetrate to a point 5 to 7 mm from the bottom of the Vicat mould.

Very Simple Defination

It is the minimum amount of water required to wet all the cement particles.

Sampling

As per IS : 3535

Temperature and Humidity

 

Temperature

Relative Humidity

Moulding Room

27 ± 2 °C

Not less than 65%

Dry Material

Water

Apparatus

  1. Vicat Apparatus (IS : 5513)
  2. Balance (1000g, Least Count - 1g)
  3. Gauging Trowel (IS : 10086)
  4. Measuring Cylinder ( 100ml)

Procedure

  1. Take 400g of cement in a tray.
  2. Take about 25% of distilled water i.e. 100g (or 100ml).
  3. Mix the water to dry cement thoroughly by Gauging Trowel. Gauging time should be 3 to 5 minutes.
  4. Take a Vicat Mould (IS : 5513) resting on a non-porous plate.
  5. And, fill the Vicat Mould with this paste.
  6. Smoothen the surface of the paste, making it level with the top of the mould.
  7. Shake the mould slightly to expel the air.
  8. Place the test block in the mould, together with non-porous resting plate, under the rod bearing the plunger of the Vicat Apparatus.
  9. Lower the plunger gently to touch the surface of the test block, and quickly release.
  10. Allow it to sink into the paste.
  11. Plunger should penetrate to a point 5 to 7mm from the bottom of the Vicat Mould.
  12. If not, again repeat the procedure with another quantity of water.

Calculation

        Normal Consistency (P) = (Weight of Water) / (Weight of Cement)  x 100

    (Express the result to the first place of decimal - As per IS : 4031, Clause 6.1 )

Precaution

  1. Clean appliances shall be used.
  2. In filling the mould, the operator’s hand and the blade of gauging trowel should alone be used.
  3. The gauging time shall be counted from the time of adding water to the dry cement until commencing to fill the mould.



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