Vicat Test – Consistency Test of Cement
To determine the quantity of water required to produce a cement paste of standard consistency as per IS: 4031 (Part 4) – 1988.
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.
Vicat apparatus conforming to IS: 5513 – 1976
Balance, whose permissible variation at a load of 1000g should be +1.0g
Gauging trowel conforming to IS: 10086 – 1982
Weigh approximately 400g of cement and mix it with a weighed quantity of water. The time of gauging should be between 3 to 5 minutes.
Fill the Vicat mould with paste and level it with a trowel.
Lower the plunger gently till it touches the cement surface.
Release the plunger allowing it to sink into the paste.
Note the reading on the gauge.
Repeat the above procedure taking fresh samples of cement and different quantities of water until the reading on the gauge is 5 to 7mm.
Express the amount of water as a percentage of the weight of dry cement to the first place of decimal.
If you add Less water than its quantity couldn’t complete chemical reaction. Thus, resulting is reduction of strain.
If you add more water would increased water cement ratio and so would reduce its strength.