What is The Normal Consistency or Standard Consistency of Cement Paste?

The normal consistency or standard consistency of a cement is defined as that consistency which will permit the Vicat plunger of 10 mm diameter to penetrate to a point 5 mm to 7 mm from the bottom of the Vicat mould when the cement paste is tested as described in procedure.


The test for Consistency of cement gives us the workability of cement. It should not be too dry or too liquid form.



The Test ‘normal consistency or standard consistency test of a cement paste’ is used to determine the required quantity of water to produce a cement paste of standard consistency. It is necessary to fix the quantity of water to be mixed in cement paste in each case for finding out initial setting time of cement, final setting time of cement, soundness of cement and compressive strength of cement.


Name of Test

Amount of Water Required

Soundness of cement (Le-Chatelier method)

0.78 P

Setting time of cement

0.85 P

Compressive strength of cement

(P/4 + 3)% of combined mass of cement and sand.

P=Consistency of standard cement paste



Factors That Affect the Standard Consistency of Cement Paste:-

The Normal consistency of cement paste depends upon the factors such as temperature and fineness of cement. Higher the temperature and higher the fineness of cement results higher the normal consistency of cement and vice versa.


Normal Consistency or Standard Consistency of Cement Lab Report
Vicat Apparatus

Normal Consistency or Standard Consistency of Cement Lab Report
Vicat-Apparatus-Diagram

Normal Consistency or Standard Consistency of Cement Test Procedure with Apparatus List and Lab Report as per IS: 4031 Part-4 (1988)


Hi friends, you are welcomed in the world of Civil Allied Gyan. Here I have explained about determination of normal consistency or standard consistency of cement. Read definition, apparatus, IS code, test procedure, formula, result, lab report about normal or standard consistency of cement by Vicat apparatus.


IS Code For Normal Consistency or Standard Consistency Test of Cement:-
  1. IS: 4031 (Part 4)-1988, Methods of physical test for hydraulic cement.
  2. IS: 5513-1996, For specification for Vicat’s apparatus.

Normal Consistency or Standard Consistency of Cement Lab Report

Apparatus Required For Normal Consistency or Standard Consistency Test of Cement:-
  1. Vicat’s apparatus conforming to IS: 5513-1976    
  2. Weighing Balance of capacity 1000g and sensitivity to 1g.
  3. Gauging trowel conforming to IS: 10086-1982.
  4. Stop Watch
  5. Dial Gauge 


What is Vicat’s Apparatus?

Vicat apparatus is a penetration device used in testing of hydraulic cements and similar materials to determine their normal or standard consistency. It is also used to determine the initial setting time and final setting time of hydraulic cements and similar materials.


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Parts of Vicat’s Apparatus with Explanation



Sampling and Selection of Test Specimen:

The samples of the cement shall be taken as per IS: 3535- 1986 and the relevant standard specification for the type of cement being tested. Mix thoroughly the cement sample before testing.



Temperature and Humidity:

Unless otherwise specified this test shall be conducted at a temperature 25ºC to 29ºC and the relative humidity of laboratory should be 60% to 70%.



Procedure of Normal Consistency or Standard Consistency of Cement Test:-

  1. Prepare a paste of weighed quantity of cement (300 g) with a weighed quantity of potable or distilled water, starting with 26% water of 300 g of cement.
  2. Take care that the time of gauging is not less than 3 minutes, not more than 5 minutes and the gauging will be completed before setting occurs.
  3. The gauging time will be counted from the time of adding the water to the dry cement until starting to fill the mould.
  4. Fill the Vicat mould with this cement paste, the mould resting upon a nonporous plate.
  5. After completely filling the mould, trim off the surface of the cement paste, making it in level with the top of the mould. The mould may slightly be shaken to expel the air.
  6. Clean appliances shall be used for gauging.
  7. In filling the mould operators hands and the blade of the gauging trowel shall only be used.
  8. Together with the non-porous resting plate, place the test block with the mould under the rod bearing the plunger (10 mm diameter).
  9. Lower the plunger gently to touch the surface of the test block and quickly release, allowing it to penetrate into the cement paste.
  10. This operation will be carried out immediately after filling the mould.
  11. Record the depth of penetration.
  12. Prepare the trial cement pastes with varying percentages of water and test as described above until the required quantity of water necessary for making the cement paste of standard consistency as defined above is obtained (until the plunger is 5mm to 7mm from the bottom of the Vicat mould).
  13. Express the quantity of water as a percentage by weight of the dry cement.

Repetition of the experiment with fresh cement is to be taken.


Observations:-

  • Type of cement………………….
  • Brand of cement…………………
  • Time of Test……………………...
  • Room Temperature……………..


Table:
Normal Consistency or Standard Consistency of Cement Paste

Calculation:-

Formula for Consistency Test of Cement:
Normal Consistency or Standard Consistency of Cement Paste

Result:-
Normal or Standard consistency for the given sample of cement paste is …………..%.

Report:-
Express the amount of water as a percentage by weight of dry cement to the first place of decimal. The average value of Normal or Standard consistency for the given sample of cement paste is reported.


Safety and Precautions While Testing:

  1. Gauging time should be strictly observed
  2. Clean the apparatus thoroughly before testing and after testing.
  3. The test should be performed away from vibrations and other disturbances.
  4. Care should be taken to maintain the specified temperature, humidity and the time of mixing so as to avoid setting of cement paste as per test requirement.


Range of the Normal Consistency for Ordinary Portland Cement (OPC):
The result is merely the water/cement ratio expressed as a percentage. There is no accurate value for this question. It may vary with respect to concreting, plastering, tiling, etc. Typical values of the normal consistency for OPC ranges from 26% to 33%.

Consistency refers to the relative mobility of a freshly mixed cement paste or mortar or its ability to flow. For a mortar the normal or standard consistency is measured by flow table test.


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