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Initial setting time of concrete is the time period between addition of water to cement till the time at 1 mm square section needle fails to penetrate the cement paste, placed in the Vicat’s mould 5mm to 7mm from the bottom of the mould. This test is required to understand the time cement takes for initial setting between mixing and transporting and placing of concrete.

Procedure to Find Setting Time of Cement

Apparatus Required

  • Vicat’s apparatus
  • Balance
  • Measuring cylinder
  • Stop watch
  • Glass plate
  • Enamel tray
  • Trowel

Test Procedure

  1. Consistency test to be done before starting the test procedure to find out the water required to give the paste normal consistency (P).
  2. Take 400 g of cement and prepare a neat cement paste with 0.85P of water by weight of cement.
  3. Gauge time is kept between 3 to 5 minutes. Start the stop watch at the instant when the water is added to the cement. Record this time (T1).
  4. Fill the Vicat mould, resting on a glass plate, with the cement paste gauged as above. Fill the mould completely and smooth off the surface of the paste making it level with the top of the mould. The cement block thus prepared is called test block.
  5. Place the test block confined in the mould and resting on the non-porous plate, under the rod bearing the needle.
  6. Lower the needle gently until it comes in contact with the surface of test block and quick release, allowing it to penetrate into the test block.
  7. In the beginning the needle completely pierces the test block. Repeat this procedure i.e. quickly releasing the needle after every 2 minutes till the needle fails to pierce the block for about 5 mm measured from the bottom of the mould. Note this time (T2).
Vicat's Apparatus used for determination of setting time of cement

Fig 1: Vicat’s Apparatus used for determination of setting time of cement

Observations

Weight of cement taken (g) = _________

Quantity of water added to cement =

=0.85 X Quantity of water required for standard consistency in ml = _____

Time at which water is first added to cement (T1)  in sec = _____

Time when needle fails to penetrate 5 mm to 7 mm from bottom of the mould (T2) in sec = _____

Calculations

Initial Setting Time = T2-T1

Result

The initial setting time of the given sample of cement= _____ min

Precautions 

Some necessary precaution taken while performing initial setting time test are,

  • Release the initial and final setting time needles gently.
  • The experiment should be performed away from vibration and other disturbances.
  • Needle should be cleaned every time it is used.
  • Position of the mould should be shifted slightly after each penetration to avoid penetration at the same place.
  • Test should be performed at the specified environmental conditions.

Standard Specification of Setting Time for Different Type of Cement

Depending upon the admixtures added into the cement in the process of manufacture of cement, the setting time differs for different cement. Standard setting times are listed in the below table as per IS  4031, IS 269.

Table-1: Setting Time for Different Type of Cement

Cement Type Initial Setting Time in Min As per IS Codes
OPC(33) 30
OPC(43) 30
OPC(53) 30
SRC 30
PPC 30
RHPC 30
PSC 30
High alumina 30
Super sulphated 30
Low heat 60
Masonry cement 90
IRS-T-40 60

 

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Gopal Mishra

Gopal Mishra

Gopal Mishra is a Civil Engineer from NIT Calicut and has more than 10 years of experience in Civil Engineering and Construction. He is the founder of The Constructor.

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