SCOPE:
In this test we will cover the determination of Setting time of cement by means of the Vicat Needle Apparatus.
APPARATUS :
a. Vicat Apparatus .
b.Weighing Device.
c.Graduated glass jar 200 ml capacity.
d.A trowel and containers.
1) Weigh 300 gram of the sample of the cement on a nonporous and platform and make it into a heap with a depression at the center.
2) Calculate the amount of water required for making paste as 0.85 of the amount of water required to make a paste of standard or normal consistency.Add the calculated quantity of water and simultaneously start the stop watch.
3) Mix the cement and water together & filled in such a manner that the mould is completely filled.Strike off the top level of the mold with the trowel and slightly tap the mold so as to expel out all entrapped air.
4) Place the mould just below Vicat needle apparatus & keep 1 mm square needle in exact position.Now release the moving rod and note the reading . Now raise the moving rod & clear off all the cement paste and wipe off the needle clear.
5) Repeat the step no:4 above at regular interval of ½ minute till the reading becomes 5 mm exactly.
6) Note down the time between adding water to dry cement to the moment when the reading is 5 mm.
7) Now remove the 1 mm needle from the rod and replace it by another needle for determining the final set.
8) As before allow the moving rod to travel downwards at every 2 minutes interval.When the needle makes a move but the metal attachment fails to do so note the total time elapsed.
9) Remove the needle, clean the apparatus with water .
RESULT:
Initial setting time of cement is ____________________
Final setting time of cement is ____________________
