In conducting a standard consistency test of Ordinary Portland cement using Vicat apparatus as per IS 4031-1988, what is the penetration depth of the needle from the top of Vicat mould, for the paste to have normal consistency?

In conducting a standard consistency test of Ordinary Portland cement using Vicat apparatus as per IS 4031-1988, what is the penetration depth of the needle from the top of Vicat mould, for the paste to have normal consistency? Correct Answer 33 to 35 mm

Explanation:

Vicat’s Apparatus

• It is used to find out the consistency, initial setting time and final setting time of the cement.
• In the normal consistency test, we have to find out the amount of water to be added to the cement to form a cement paste of normal consistency.
• Vicat's apparatus consists of an arrangement to hold the plunger of 10 mm diameter and two other needles which are made to freely fall into a mold filled with the cement paste and the amount of penetration of the needles of plunder can be noted using the vertical graduations from 0 mm to 50 mm. 
• The length of the needle varies from 40 mm to 50 mm.
• Standard consistency is defined as the consistency of the cement paste that permits the penetration of circular vicat’s plunger of 10 mm dia and height 50 mm up to the depth of 5 - 7 mm from the bottom into the mould or 33 to 35 mm from the top of the mould.
• The needle of diameter 1 mm is used and the center needle of the attachment of the Vicat plunger projects the circular cutting edge by 0.5 mm as can be observed in the figure below:

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