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SETTING TIME
The time interval for which the cement product remains in plastic
condition is known as the setting time.
Initial Setting
Time
Final Setting Time
Ordinary Portland
Cement
30 min
10 hrs
Rapid Hardening
Cement
30
min 10
hrs
Low Heat
Cement 60
min
10 hrs
INITIAL SETTING TIME
Initial setting time is the time elapsed between the moment that
the water is added to the cement, to the time that the paste starts losing its
plasticity.
PROCEDURE
Take 500gms of cement sample and gauge it with 0.85 times of water
required to produce a standard consistent cement paste. Fill the cement paste
in Vicat’s mould within 3-5minutes. Start the stop watch, the moment water is
added to the cement.
The initial setting time is the time elapsing between the time when
the water is added to the cement and the time at which the needle penetrates to
a depth of 33-35mm in the test block. But initially the needle gets penetrated
completely into the mould.
FINAL SETTING TIME
Final setting time is the time elapsed between the moment when the water
is added to the cement and the time when the paste has completely lost its
plasticity. This time should not be more than 10hrs.
PROCEDURE
Take 500gms of cement sample and gauge it with 0.85 times of water
required to produce a standard consistent cement paste. Fill the cement paste
in Vicat’s mould within 3-5minutes. Start the stop watch, the moment water is
added to the cement.
Replace the needle of Vicat’s apparatus by a circular arrangement. The
cement shall be considered as finally set, when upon lowering the attachment
gently cover the surface of the test block, the centre needle makes an
impression, while the circular cutting edge of the attachment fails to do so.
The paste is said to have attained final setting time, when the
centre needle does not pierce through the paste more than 0.5mm.
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