The Consistency of cement test is performed to determine the amount of water content that is to be added in cement to attain Standard consistency or normal consistency of cement.
Amount of water added in cement to penetrate the Vicat plunger up to a depth of 5–7mm from the bottom of the Vicat mold or 33–35mm from top of the Vicat Mould.
When water is mixed with cement, it starts hydration. Excessive addition of water in cement results in an increase in Water cement ratio & ultimately cement loses its strength when it hardens. If Less water is added than required, Cement isn’t properly hydrated and results in loss of strength.
The Standard or Normal consistency for Ordinary Portland cement varies between 25–35%.
To prepare a mix of cement paste of Standard consistency 25–35% of water is added to the cement.
To explain in detail Let us assume a standard consistency is 30%.
Take 400g of Cement for this quantity, Add 30% of Water. i.e., 120g of water content is added in cement to attain standard consistency.