Standard Consistency Test Of Cements
Apparatus Required: Vicat's Mould
Theory: The standard consistency of cement is defined as that consistency which will permit a vicat plunger having diameter 10mm & 50mm length to penetrate a depth of 33 to 35 mm from the top or 5 to 7 mm from the bottom of the mould.
Procedure :
I. To prepare the paste take 300 gm of cement and place it in a curicible.
II. Mix water approximately 24% by weight of cement for the first trial.
III. The time of mixing or gauging not be less than three minutes nor more than five minutes and gauging time should be counted from the time of adding water to the dry cement until commencing to fill the Mould.
IV. The vicat Mould is filled with the paste, which is levelled off at it's top.
V. The mould is placed under the Vicat's plunger.
VI. The vicat plunger is brought down to touch the surface of the past eying the mould and quickly released allowing it to sink into the paste by its own weight.
VII. Take the reading by noting the depth of penetration of the plunger.
Similarly conduct the trials with higher water /cement ratios till such time the plunger penetrates for a depth of 33 to 35 mm from the top.
VIII. That particular % of water is known as percentage of water required to produce a cement paste of standard consistency.
IX. It's denoted by P.