DETERMINE THE INITIAL AND FINAL SETTING TIME OF CEMENT

 

EQPT/MATERIAL

  • Vicat Apparatus with Initial Set Needle
  • Final Set Attachment
  • Stop Watch
  • Portland Cement
  • Water

 PROCEDURE

  1. Neat cement paste shall be formed by mixing cement with the quantity of water required to give a paste of standard consistence.
  2. Vicat mould shall be completely filled and the surface of the paste shall then be smoothed off, level with the top of the mould. While testing, temperature of the material and the test room should be 17.7 to 23.3⁰
  3. For the determination of the initial setting time the test block confined in the block/mould and resting on the plate shall be placed under the rod bearing needle. This shall then be lowered gently in contact with the surface of the test block and quickly released and allowed to sink in. This process shall be repeated until the needle, when brought to contact with the test block and released as describe above, does not penetrate beyond the point approx. 5±1 mm, from the bottom of the mould (34-35mm penetration from the top).
  4. The period elapsing between the time when the water is added to the cement and the time at which needle ceased to pierce the test block is called the Initial setting time.
  5. For the determination of final setting time, the same needle shall be used. The cement shall be considered as finally set when, upon applying the needle gently to the surface of the test block, only the needle makes an impression, while the attachment fails to do so.
  6. If the scum is formed on the surface of the test block, then underside of the test block may be used for determining the Final Set.

 

PRECAUTIONS

  1. The needle should be allowed to touch the surface of cement in the cement paste.
  2. After every reading the needle should be cleaned.

 

DETAILS OF READINGS/OBSERVATIONS

  1. Type of cement
  2. Room temperature
  3. Temperature of the mixing water
  4. Humidity

At the end following table should be filled to complete report.

 

S/ No. AMOUNT OF WATER

(%)

PENETRATION

(mm)

INITIAL SETTING TIME

(Minutes)

FINAL SETTING TIME

(Minutes)

1        
2        
3        
4        
5        

 

INTERPRETATION/COLLECTION OF THE OBSERVED READINGS, GRAPHS, ETC LEADING TO RESULTS

To be done with standard specification of ASTM Designation C 150, and B.S 12:1978

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