This test is to determine the initial and final setting time
Initial and Final Setting Time of cement
Needle for initial setting time
Needle for final setting time
Take 400g of cement in a pan .Prepare a neat cement paste by adding 0.85 times the water required to give a paste of standard by the previous test .Start stopwatch at the instant when water is added to the water .
Keep the vicat mould on a non-porous plate and fill the cement paste in it.
After compleatly filling the mould, it should be shakken slightly to expel the air.Smooth off the surface of the cement paste making it level with the top of the mould.
Determination of initial setting time
Place the test block and the non-porous plate under the rod bearing the needle having 1mm2 cross section.Lower the needle gently till in contact with the surface of the test block and quickly release allowing it to penetrate into the test block.
In the beginning the needle will completely pierce the block,Repeat the procedure until the needle fails to pierce the block for 5+-0.5mm measured from the bottom of the mould.
The period elapsing between time when water is added to the cement and the time at which needle fails to pierce the test block by 5+-0.5mm in the initial setting time
Determination of final setting time
For the determination of final setting time, replace the needle for initial setting time with the annular attachment for final setting time.
The cement shall be considered as finally set, when upon applying the needle gently to the surface of the test block,the needle makes an impression there on,while the attachment fails to do so
.The period elapsing between the times when water added to the cement and the time at which the needle fails to make an impression on the surface of the test block shall be the final setting time.