Determination Of Consistency Of Standard Cement Paste -

STANDARD

DEFINITION

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.

APPARATUS

PROCEDURE

Unless otherwise specified this test shall be conducted at a temperature 27 ± 2°C and the relative humidity of laboratory should be 65 ± 5%.
Prepare a paste of weighed quantity of cement (300gm) with weighed quantity of potable or distilled water, taking care that the time of gauging is not less than 3 minutes nor more than 5 minutes and the gauging is completed before any sign of setting occurs.
The gauging is counted from the time of adding water to the dry cement until commencing to fill the mould.
Fill the vicat mould with this paste resting upon a non-porous plate.
Smoothen the surface of the paste, making it level with the top of the mould.
Slight shake the mould to expel the air.
In filling the mould operators hands and the blade of the gauging trowel shall only be used.
Immediately place the test block with the non-porous resting plate, under the rod bearing the plunger.
Lower the plunger gently to touch the surface of the test block and quickly release, allowing it sink into the paste.
Record the depth of penetration.
Prepare trial pastes with varying percentages of water and test as described above until the plunger is 5mm to 7 mm from the bottom of the vicat mould.

CALCULATIONS

Standard consistency (%) = (Weight of water added / Weight of cement ) x 100

REPORT

Express the amount of water as a percentage by mass of dry cement to the first place of decimal.

PRECAUTION

Care shall be taken to maintain the specified temperature, humidity and the time of mixing so as to avoid setting of cement paste.

DETERMINATION OF CONSISTENCY OP STANDARD CEMENT PASTE
15:4031 (Part 4) 1988

Determination Of Consistency Of Standard Cement Paste