What is Vicat Apparatus?
Vicat apparatus is a penetration device used in testing of hydraulic cements and similar materials to determine their normal or standard consistency. It is also used to determine the initial setting time and final setting time of hydraulic cements and similar materials.
What is the IS Code for Vicat Apparatus?
Vicat apparatus have to conforming the IS: 5513 (1996).
Explanation of Vicat’s Apparatus:
The Vicat’s apparatus for consistency test of cement paste consists of a frame having a movable rod with a cap at one end and at the other end any one of the following attachment, which are interchangeable:
- Needle for determining the initial setting time
- Needle for determining the final setting time
- Plunger for determining the standard consistency
The other two needles are made to freely fall into a Vicat mould filled with the cement paste and the amount of penetration of the needles of plunger of 10 mm diameter can be noted using the vertical graduations from 0 mm to 50 mm.
Parts of Vicat Apparatus with Explanation:-
- Needle for Initial Setting Time: The needle is having a cross sectional area of 1mm². The end of the needle is flat.
- Needle for Final Setting Time: The needle is circular and is having a cross sectional area of 1mm². The needle is fitted with a metal attachment. The end of needle projects beyond the cutting edge of the hollowed out metal attachment.
- Plunger for Standard Consistency
- Plunger is made of polished brass with a projection at the upper end for insertion into the movable rod. The lower end is flat.
- Movable rod carries an indicator which moves over a graduated scale attached to the frame (certain models have an additional attachment of dash pot, which facilitates lowering of movable rod slowly).
- Graduated scale is 40 mm in length and the shortest division of scale is 1 mm.
- Single mould: The Vicat mould is in the foam of a frustum of a cone having an internal diameter of 60 ± 0.5 mm at the top, 70 ± 0.5 mm at the bottom and height 40 ± 0.5 mm.
- Split type Vicat mould: The split type Vicat mould is used as an alternative to single mould. This mould consist of a split ring having an internal diameter 80 ± 0.1mm and a height 40 ± 0.5mm. A non-porous base plate is provided. The split mould is provided with a suitable clamping ring.
Vicat Apparatus is Used For:-
- Vicat apparatus is generally used to determine the required quantity of water to produce a cement paste of normal or standard consistency. It is also used in the tests for initial setting time of cement or concrete and final setting time of cement or concrete. This unit can be modified for testing to determine a false set of cement or mortar paste.
