Standard Consistency Test of Cement

This test method is conducted to establish the amount of water necessary to develop hydraulic cement pastes with normal consistency, useful for specific standard tests.

Standard Consistency: The ratio of water needed to develop standard cement paste while vicat plunger go through under 10±1mm reading is called standard consistency or normal consistency cement paste.

Equipments and Materials: The following equipments and materials are required for conducting the test :-

Electrical Balance, Vicat Apparatus, Spatula, Trowel, Mould, Pot, Distilled Water and Ordinary Portland Cement etc.

Method:

1. Select ordinary Portland cement of 500 grams and weight it in the electrical balance.

2. Choose 26-33% of water to cement. It is recommended to select 26 % (130ml) water in a graduated cylinder in first trial.

3. Now use a pot and provide the cement and water in it and blend through a trowel.

4. Make a ball with the cement paste manually then press the ball into the larger end of the conical mould, keep the other hand by entirely filling the mould with cement paste.

5. Eliminate the unnecessary cement paste from the mould by using a spatula and arrange the mould under the plunger needle of 1mm.

Also Read: How to calculate the volume of slump mould

6. Firm the plunger at the level in order that it gets in touch with the surface of cement paste and then set the changeable indicator of vicat equipment to upper zero mark of the scale and smoothly discharges the plunger to cement paste to get through for 30 seconds.

7. Note the penetration of plunger into the cement paste. It should be 10±1mm, in case it does not happen, then do the entire method again by modifying the percentage amount of water in each trial.

Precautions:

1. The blending of cement should be performed in non-porous glass plate.

2. The plunger needle should be cleansed each time prior to penetration in the cement paste.

3. Vicat apparatus should not be vibrated throughout the penetration.

Examinations and Calculations:

Weight of Cement = W1

Water provided in graduated cylinder = W2

% water in W1gm cement = W2 / 100 W1