The Vicat Apparatus is used to determine the consistency, Initial and Final setting time of cement.
The Vicat apparatus shall consist of a frame D having a movable rod B with a platform A at one end and the following which can be attached at the other end:
- Needle C for determining the initial setting time,
- Needle F for determining the final setting time, and
- Plunger G for determining the standard consistency.
Vicat Apparatus
The needles C, F and plunger G-shall be capable of being fixed centrally into the movable rod B by means of clamping screw as indicated in Fig. above. Their movement shall be truly vertical and without appreciable friction, and their axis shall coincide with that of the needle or plunger.
- Dimensions of Needles
Needle C shall be round of diameter 1.13 ± 0.05 mm. The needle shall have a flat end. The effective length, excluding the hilt shall be 50 ± 1 mm (see Fig. above).
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| Needle C (diameter 1.13 ± 0.05 mm)
Used in Initial Setting time test |
Needle F (Diameter 5 ± 0.1 mm
Used in Final Setting time test |
Needle F shall be of the same section as needle C but shall be 30 ± 1 mm in length, excluding the hilt, and fitted with a brass attachment hollowed out so as to leave a circular cutting edge 5 ± 0.1 mm in diameter.
The depth hollowed out shall be 0.5 ± 0.1 mm. A 0.75 mm diameter vent hole shall be provided as shown. The needle shall project 0.5 ± 0.1 mm beyond the cutting edge (see Fig.).
- Plunger
Plunger G shall be of polished brass 10 ± 0.05 mm in diameter with a projection at the fitting end for insertion into the movable rod B. The lower edge shall be flat. Its length shall be 50 ± 1 mm (see Fig. above).
- Movable Rod
Movable rod B shall carry an indicator which moves over a graduated scale attached to the frame D. A clearance of 0.25 mm around the movable rod is recommended to facilitate free movement. A suitable arrangement shall be provided to secure the movable rod in rest position when the apparatus is not in use (see Fig.).
- Graduated Scale
Graduated scale shall be 40 mm in length and the smallest division of the scale shall be 1 mm (see Fig.).
- Vicat Mould
The Vicat mould shall be of truncated conical form with an internal diameter of 70 ± 5 mm at the top, 80 ± 5 mm at the bottom and a height 40 ± 0.2 mm. The mould shall be adequately rigid and shall have a minimum wall thickness of 4 mm. A non-porous glass or Stainless-Steel base plate shall be provided. A plate of glass or stainless steel of at least 2.5 mm thickness is suitable.
- Mass
The total mass of the moving unit, when in use, complete with all attachments, that is, the cap and rod together with either needle C or needle F or plunger G, shall be 300 + 1 g.
Needle C, needle F and plunger G shall each weigh 9 ± 0.5 g.
- MARKING:
The following information shall be clearly and indelibly marked on the Vicat apparatus in such a manner that it does not interfere with the performance of the apparatus:
- Indication of the source of manufacture,
- Date of manufacture,
- Serial number/Batch number, and
- Type of mould.
Frequently Asked Questions (FAQ)
Q1. What is Vicat Apparatus?
Ans: Vicat Apparatus is used to determine the consistency, Initial and Final setting time of cement.
The Vicat apparatus shall consist of a frame D having a movable rod B with a platform A at one end and the following which can be attached at the other end:
- Needle C for determining the initial setting time,
- Needle F for determining the final setting time, and
- Plunger G for determining the standard consistency.
Q2. What is Plunger?
Ans: Plunger is used for determining the standard consistency of cement.
Plunger shall be of polished brass 10 ± 0.05 mm in diameter with a projection at the fitting end for insertion into the movable rod B. The lower edge shall be flat. Its length shall be 50 ± 1 mm.
Q3. What tests are performed by Vicat Apparatus?
Ans: Vicat apparatus is used to determine the following :
- Standard Consistency of Cement paste,
- Initial Setting time of cement, and
- Final Setting time of cement.
Q4. What is the dimension of needles attached in Vicat Apparatus?
Ans: The dimensions of needles and plunger is as follows:
- Needle C shall be round of diameter 1.13 ± 0.05 mm. The needle shall have a flat end. The effective length, excluding the hilt shall be 50 ± 1 mm.
- Needle F shall be of the same section as needle C but shall be 30 ± 1 mm in length, excluding the hilt, and fitted with a brass attachment hollowed out so as to leave a circular cutting edge 5 ± 0.1 mm in diameter.
- Plunger G shall be of polished brass 10 ± 0.05 mm in diameter with a projection at the fitting end for insertion into the movable rod B. The lower edge shall be flat. Its length shall be 50 ± 1 mm.