What is the Soundness of Cement by Le-Chatelier’s Method?
One of the most important
properties of cement is its soundness. Soundness of cement is the
ability to retain its volume after it gets hardened (or after setting). The
test performed to find out the excess amount of lime percentage
in cement is known as soundness test of cement.
We can determine the soundness of cement by two methods, namely Le-Chatelier method and Autoclave
method. Here the procedure of Le-Chatelier method is mentioned below.
In the soundness test of cement by Le-Chatelier method, a
specimen of hardened cement paste is boiled for a fixed time so that any
tendency to expand is speeded up and can be detected. Soundness means the ability
to resist volume expansion.
What are the Causes of Unsoundness in Cement?
Unsoundness in cement is caused by expansion of some of
the constituents like free lime produced in the manufacturing process of
cement paste. Another possible case of unsoundness is the presence of too high a
magnesia content in the cement and presence of excess of lime than that could
be combined with acidic oxide at kiln.
Soundness of Cement Test by Le-Chatelier's Apparatus, IS: 4031 (Part 3)-1988
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friends, you are welcomed in the world of Civil Allied Gyan. Read definition,
apparatus, IS code, test procedure, formula, result, lab report
and significance of soundness of cement by Le-Chatelier's apparatus.
IS Code for Soundness of Cement Test by Le-Chatelier’s Method:-
- IS: 4031 (Part 3)–1988, Methods of physical test of hydraulic cement
Apparatus Required for Soundness Test of Cement by Le-Chatelier's Method:-
- Le-Chatelier’s Apparatus
- Weighing Balance
- Water Bath
- Measuring Cylinder
Procedure of Soundness of Cement Test by Le-Chatelier's Apparatus:-
- Prepare a cement paste specimen formed by gauging cement with 0.78 times water rag to give a paste of standard (or normal) consistency. The gauging time should neither be less than 3 minutes nor be greater than 5 minutes.
- On the inner surface of mould.
- Place the mould on glass sheet and fill it with cement paste specimens taking care to keep the edges of the mould gently together cover the mould with another piece of glass sheet and place a little weight on this covering glass sheet and immediately submerge the entire assembly in water at a temperature of 27 °C and keep it for twenty four (24) hours.
- Take out the assembly from water after 24 hours and measure the distance flow the indicator points and record it.
- Submerge the mould again in water in 25 to 30 minutes.
- Remove the mould from the water.
- Allow it to cool and measure the distance flow the indicator points & record it. The difference between two measurements represents the same expansion of cement.
- The sample should be tested and average of the results should be reported.
Observations:-
Type of Cement Tested
|
|
Initial Length of The Specimen L₁
|
|
Final Length of The Specimen L₂
|
|
Expansion of The Specimen (L₁- L₂ )
|
Result:-
Soundness
of cement =……………
Why We Measure the Soundness of Cement?
Soundness of cement is the strength of cement to maintain its volume as soon as it gets hardened (or solidified). Once the cement mortar or concrete gets dried after used in structure, there should not be any alteration in the volume of cement. If any alteration in the volume of cement occurs, it will allow the cement to inflate or contract. So, we may see the cracks in the structure. The expansion beyond certain limit of soundness indicates unsoundness of cement which affects durability of the structure in which the cement is used.
