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Ricardo Kuhn
Construction Foreman
Asked a question last year

How to check the purity of cement?

How to check the purity of cement?

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Wilma Caldwell
Architectural technologist
  • Color test – It sould be uniform light greenish grey.
  • Presence of lumps – There should not be any hard lumps or any other impurities.
  • Adulteration test – Taken pinch of cement in between fingers, it should be smooth, not rough.
  • Temperature test – When inserted hand in cement bag, it should feel cool.
  • Float test – Handful of cement if thrown in a bucket full of water, its particles should float on surface for sometime.
  • Setting test – Thick paste of cement with water is made on a piece of glass plate and

it skipped under water for 24 hours so after 24 hours it will sit and not blend or crack in water.

  • Date of packing – Remember the strength of cement reduces with time so it’s important to check the manufacturer time. Cement should be used before 90 days from manufacturing date.

The purity of cement can be checked by following ways :-
1. RUBBING :- Take a small quantity of cement between your fingers and rub it. It must feel smooth while rubbing but if it feels rough than adulteration with sand.

2. HAND INSERTION :- Insert your hand into the cement bag and it should give cool feeling. Hence this cool feeling indicates that there is no hydration reaction is taking place in the bag.

3. FLOAT TEST :- It is tested by throwing a small quantity of cement in a bucket of water. Thus it should sink and should not float on the surface.

4. SMELL TASTE :- Take some quantity of cement and smell it. If the cement contains too much of pounded clay and silt as an adulterant, the paste will give an earthy smell.

5. PRESENCE OF LUMPS :- See that the lumps should not be present in the bag while opening the bag. Thus it ensures that no setting has taken place.

6. COLOUR :- Basically, the cement should be uniform in colour. Generally the colour of cement is grey with a light greenish shade. The colour of cement gives an indication of excess lime or clay and the degree of burning.

7. DATE OF PACKING :- Date of manufacturing should be seen on the bag. It is most important because the strength of cement reduces with age.