1.3 INITIAL AND FINAL SETTING TIME
AIM
To determine the initial and the final setting time of cement
as per IS: 4031 (Part 5) - 1988.
APPARATUS
i) Vicat apparatus conforming to IS: 5513 - 1976
ii) Balance, whose permissible variation at a load of 1000g
should be +1.0g
iii) Gauging trowel conforming to IS: 10086 - 1982
PROCEDURE
i) Prepare a cement paste by gauging the cement with 0.85
times the water required to give a paste of standard
consistency (see Para 1.2).
ii) Start a stop-watch, the moment water is added to the
cement.
iii) Fill the Vicat mould completely with the cement paste
gauged as above, the mould resting on a non-porous plate
and smooth off the surface of the paste making it level with
the top of the mould. The cement block thus prepared in the
mould is the test block.
A) INITIAL SETTING TIME
Place the test block under the rod bearing the needle.
Lower the needle gently in order to make contact with the
surface of the cement paste and release quickly, allowing it
to penetrate the test block. Repeat the procedure till the
needle fails to pierce the test block to a point 5.0 ± 0.5mm
measured from the bottom of the mould.
to the cement and the time, the needle fails to pierce the
test block by 5.0 ± 0.5mm measured from the bottom of the
mould, is the initial setting time.
B) FINAL SETTING TIME
Replace the above needle by the one with an annular
attachment.
The cement should be considered as finally set when, upon
applying the needle gently to the surface of the test block,
the needle makes an impression therein, while the
attachment fails to do so. The period elapsing between the
time, water is added to the cement and the time, the needle
makes an impression on the surface of the test block, while
the attachment fails to do so, is the final setting time.
REPORTING OF RESULTS
The results of the initial and the final setting time should be
reported to the nearest five minutes.