Take about 500 gms cement and prepare a paste with a weight quantity of water (say 24 percent by weight of cement) for the first trial.
The paste must be made in a conventional manner and filled into the Vicat mold within 3-5 minutes.
After complete filling, the mold shakes the mold to expel air.
A standard plunger 10mm diameter, 50mm long is attached and brought down to touch the surface of the paste in the test block & quickly released, allowing it to sink into the paste by its own weight.
Take the reading this reading note down the depth of penetration of the plunger.
Conduct a 2nd trial (say with 25 percent of water) and find out the depth of penetration of plunger. Similarly,
Conduct trials with higher water/cement ratio till such time of plunger penetrates a depth of 33-35 mm from the top.
That particular percentage of water maximum allows the plunger to percentage only to a depth 33-35mm from the top is known as the %(percentage) of the water required to produce the cement paste of standard consistency.
The test is expected required to be conducted at a constant temperature (27°± 2°) C & constant humidity (90%)