Tips to ascertain Standard Consistency of Cement
The standard consistency of cement facilitates the vicat plunger to infiltrate to a point 5 to 7mm from the bottom of the vicat mould at the time of testing it. Given below, the detail method for finding out the quantity of water necessary to form a cement paste maintaining standard consistency.
The tools required for Standard Consistency:
1. Vicat Apparatus: The vicat apparatus comprises of a frame that includes a changeable rod having a cap at one end and at the other end any one of the following replaceable attachment.
a. Needle for deciding the initial setting time
b. Needle for deciding the final setting time
c. Plunger for verifying the standard consistency
2. Needles: Needle for Initial Setting Time.
The needle contains a cross sectional area of 1mm2. The end of the needle remains flat.
Needle for FInal Setting Time: The needle is circular in shape and comprises of a cross sectional area of 1mm2. The needle is set up with a metal attachment. The end of the needle projects ahead of the cutting edge of the hollowed out metal attachment.
Plunger for Standard Consistency: It is made of polished brass 10 ± 0.05mm in diameter with a protrusion at the upper end for placing into the movable rod. The lower end is flat.
3. Movable Rod: Movable rod bears an indicator which moves over a graduated scale associated with the frame (specific models contain a supplementary attachment of dash pot, that allows reduction of movable rod slowly).
4. Graduated Scale: The length of the graduated scale is 40mm and the smallest division of scale is 1mm.
5. Vicat Mould
Single mould: The vicat mould remains in the foam of a frustum of a cone that contains an internal diameter of 60+/-0.5mm at the top, 70 +/- 0.5mm at the bottom and height 40 +/_ 0.5mm.
Split type vicat mould: The split type vicat mould substitutes the single mould. This mould comprises of a split ring with an internal diameter 80+/- 0.1mm and a height 40+/_0.5mm. There is also a non-porous base plate. The split mould is arranged with a appropriate clamping ring.
To know the process for checking standard consistency of cement, go through the following link civilengworks.com