Soundness of cement is determined by Le-Chatelier method as per IS : 4031 (Part 3) – 1988.
Apparatus – The apparatus for conducting the Le-Chatelier test should conform to IS : 5514 – 1969 Balance, whose permissible variation at a load of 1000g should be +1.0g and Water bath.
Procedure to determine soundness of cement
Place the mould on a glass sheet and fill it with the cement paste formed by gauging cement with 0.78 times the water required to give a paste of standard consistency.
Cover the mould with another piece of glass sheet, place a small weight on this covering glass sheet and immediately submerge the whole assembly in water at a temperature of 27 ± 2oC and keep it there for 24hrs.
Measure the distance separating the indicator points to the nearest 0.5mm (say d1 ).
Submerge the mould again in water at the temperature prescribed above. Bring the water to boiling point in 25 to 30 minutes and keep it boiling for 3hrs.
Remove the mould from the water, allow it to cool and measure the distance between the indicator points (say d2 ).