How to determine the initial and final setting times of cement
AIM:
To determine the initial and final setting times of cement.
APPARATUS:
The Vicat’s apparatus, Needle, Annular ring, Trays, Balance and Weights.
PROCEDURE
1. Preparation of Test Block: Prepare a neat cement paste by gauging the cement with 0.85 times the water required to give the paste of standard consistency. Start a stopwatch at the instant when water is added to the cement. Fill the Vicat’s mould with a cement paste with in three to five minutes after addition of water. Fill the mould completely and smooth off the surface of this paste making it level with the top of the mould. The cement block thus prepared in the mould is test block.
2. Clean appliances shall be used for gauging. The temperature of water and that of the test room at the time of gauging shall be with in (27 2) 0C.
3. During the test the block shall be kept at a temperature of (27 +/- 2) Degree and at least 90% relative humidity.
a) Determination of Initial Setting Time:
Place the test block confined in the mould and resting on the nonporous plate, under the rod bearing the needle, lower the needle gently 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 test block. Repeat this procedure until the needle, when brought in contact with the test block and released as described above, fails to pierce the block for 5 to 7 mm measured from the bottom of the mould. The period elapsing between the time when water is added to the cement and this time shall be initial setting time. Aurora’s Technological & Research Institute Concrete and Highway Engineering Lab Department of Civil Engineering
b) Determination of Final Setting Time:
Replace the needle of the Vicat’s apparatus with the needle with a circular attachment. The cement shall be considered as finally set, when upon lowering the needle gently to the surface of the test block the needle makes an impression there on, while the attachment fails to do so. In other words the paste has attained such hardness that the centre needle does not pierce through the paste more than 0.5mm. The period elapsing between the time when water is added to the cement and the time at which the needle makes an impression on the surface on the test block while the attachment fails to do so shall be the final setting time.
OBSERVATIONS:
INITIAL SETTING TIME: Time Reading on the scale of Vicat’s apparatus
FINAL SETTING TIME: Time Reading on the scale of Vicat’s apparatus
RESULT:
SPECIFICATION: As per IS 269 – 1989
The initial setting time should not be less than 30 minutes and final setting time should not be more than 600 minutes for ordinary Portland cement.
AIM:
To determine the initial and final setting times of cement.
APPARATUS:
The Vicat’s apparatus, Needle, Annular ring, Trays, Balance and Weights.
PROCEDURE
1. Preparation of Test Block: Prepare a neat cement paste by gauging the cement with 0.85 times the water required to give the paste of standard consistency. Start a stopwatch at the instant when water is added to the cement. Fill the Vicat’s mould with a cement paste with in three to five minutes after addition of water. Fill the mould completely and smooth off the surface of this paste making it level with the top of the mould. The cement block thus prepared in the mould is test block.
2. Clean appliances shall be used for gauging. The temperature of water and that of the test room at the time of gauging shall be with in (27 2) 0C.
3. During the test the block shall be kept at a temperature of (27 +/- 2) Degree and at least 90% relative humidity.
a) Determination of Initial Setting Time:
Place the test block confined in the mould and resting on the nonporous plate, under the rod bearing the needle, lower the needle gently 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 test block. Repeat this procedure until the needle, when brought in contact with the test block and released as described above, fails to pierce the block for 5 to 7 mm measured from the bottom of the mould. The period elapsing between the time when water is added to the cement and this time shall be initial setting time. Aurora’s Technological & Research Institute Concrete and Highway Engineering Lab Department of Civil Engineering
b) Determination of Final Setting Time:
Replace the needle of the Vicat’s apparatus with the needle with a circular attachment. The cement shall be considered as finally set, when upon lowering the needle gently to the surface of the test block the needle makes an impression there on, while the attachment fails to do so. In other words the paste has attained such hardness that the centre needle does not pierce through the paste more than 0.5mm. The period elapsing between the time when water is added to the cement and the time at which the needle makes an impression on the surface on the test block while the attachment fails to do so shall be the final setting time.
OBSERVATIONS:
INITIAL SETTING TIME: Time Reading on the scale of Vicat’s apparatus
FINAL SETTING TIME: Time Reading on the scale of Vicat’s apparatus
RESULT:
SPECIFICATION: As per IS 269 – 1989
The initial setting time should not be less than 30 minutes and final setting time should not be more than 600 minutes for ordinary Portland cement.
