Standard Consistency of cement
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For the determination of the initial setting time, the final setting time, and for Le Chatelier soundness tests, neat cement paste of a standard consistence has to be used. Therefore, it is necessary to determine for any given cement the water content which will produce a paste of standard consistence. The standard consistency of cement is between 26 and 33 (expressed a percentage by mass of dry cement).
To find the amount of water required to produce a cement paste of standard consistency.
Ordinary Portland cement.
Vicat apparatus with the mould and it's 10 mm diameter plunger for consistency test.
Weighing balance with capacity at least 2000 gram.
Zeroing Vicat apparatus (the 10 mm plunger attach the base of the mould).
Prepare the paste by adding the amount of water (25,30, and 35 % of the mass of dry cement) to 600 gm of cement, and mixing for 4±1/4 minutes.
Form the cement paste into the approximate shape of ball with gloved hands. Then toss six times through a free path of a bout 150 mm from one hand to another. Press the ball resting on the palm of one hand into the mould, and then remove the excess.
Center the paste confined in the mould, resting on the base plate under the plunger.
Let the plunger contact the surface of the paste.
Release the plunger immediately to penetrate the paste (this must not exceed 30 seconds after completion of mixing).
Read the gauge or the penetration depth taking the distance from the base plate to the tip of the plunger.