The initial Setting time of the Cement testing procedure in details

The initial Setting time of the Cement testing procedure in details

OBJECTIVE:

This method covers the testing procedure for determining the initial setting time of cement.

APPARATUS:

Vicat apparatus conforming to IS: 5513-1969 with dashpot, non-absorbent mixing plate, measuring cylinder, gauging

trowel and stopwatch.

PROCEDURE:

1. Take the Vicat apparatus and fit the standard consistency plunger (needle type). Lower the stem and check if the reading

is zero when the plunger touches the non-porous resting plate (glass plate). If not adjust it to zero.

2. The temperature of cement and water and that of the testing room shall be preferably within the range of temperature

3. Coat the non-porous resting plate (glass plate) with petroleum jelly. Place the mold after coating lightly with petroleum

jelly on the non-porous resting plate (glass plate)

4. Take 300 g of cement.

5. Prepare a neat cement paste mixed with water which is 0.85 times that of standard consistency (i.e. standard consistency

=30%). Water for initial setting time =0.30x300x0.85= 76.5 ml.

6. The time from adding water to dry cement until starting to fill the Vicat Mould should be within 3 to 5 minutes.

7. Start the stopwatch as soon as you start adding water and mixing the cement paste. The mixing should be done using

stainless steel trowel which is available with lab equipment dealers.

8. Fill the vVicat Mould completely with the cement paste made and smooth off the surface of the paste make it level to the

top of the Mould.

9. Place the Mould under the needle (1 mm square) together with a non-porous resting plate and cement paste make it level to

the top of the Mould.

10. Lower the needle gently to touch the surface of the block and release quickly. Make sure that the dashpot works

properly.

11. Initially, the needle will pierce completely into the test block .Repeat this procedure until the needle fails to penetrate

into the test block by 5± 0.5 mm from the bottom of the mould.

12. The time started from mixing water to the cement to the time when the needle fails to penetrate test block by 5 ± 0.5

mm is described as the initial setting time.