Kathmandu University Civil Labs
SOUNDNESS TEST ON CEMENT
OBJECTIVE:
To determine the soundness of the given cement sample by Le-chatelier method.
APPARATUS REQUIRED:
1. Le-chatelier apparatus
2. two glass plates
3. temperature control water bath
4. scale.
Le-chatelier apparatus consists of a small split cylinder of spring brass or other suitable metal of 0.5 mm
thickness forming a mould of 30 mm internal diameter and 30 mm high. On either side of the split are
attached two indicators with pointed ends A-A, the distance from these ends to the centre of the cylinder
being 165 mm. The mould shall be kept in good condition with the jaws not more than 0.5 mm apart.
THEORY:
Soundness indicates the ability of the cement to maintain constant volume, which means no appreciable
change in the volume of cement should be taken place after setting of cement. Generally free lime, magnesium
and calcium sulphate are responsible for volumetric change after setting of cement due to which cracks
may takes place. This types of phenomenon is known as unsoundness. This is also due to inadequate
burning or insufficiency in fineness of grinding or thorough mixing of raw materials.
The unsoundness of cement causes serious difficulties for the durability of structures.
In the soundness test, 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.
PROCEDURE:
1. Prepare the cement paste as an inconsistency test with 0.78 times the water required to give a paste
of standard consistency.
2. Fill the cement paste in Le-chatelier mould taking care to keep the edges of the mould gently
together during the operation.
3. Cover the mould with another piece of glass plate a small weight over the cover plate.
4. Submerge the whole assembly immediately in the water at a temperature of 27 ± 2oC and keep it
there for 24 hours.
5. Take out the assembly again in the water at 27 ± 2oC.
6. Submerge assembly again in the water at 27 ± 2oC.
7. Bring the water to boiling in 25 to 30 minutes and keep at boiling for 3 hours. The assembly
should be immersed in water during this process.
8. Remove the mould from water and allow it to cool to 27 ± 2oC.
9. Measure the distance between the indicator points (B).
10. The difference (B-A) between the two measurements gives an expansion of cement and it should not
be more than 10 mm according to IS specifications.
OBSERVATIONS AND CALCULATIONS:
The initial distance between the indicator points A = ...... mm
Final distance between the indicator points B =....... mm
Expansion of Cement B-A = ........ mm
PRECAUTIONS:
1. Note the measurements A and B should be taken very accurately
2. Do not apply extra pressure while filling the moulds.
3. The lime sample should be kept for 3 hours in a steam boiler but it should never be immersed.
4. Cooling the samples should be gradual.
CONCLUSION:
Please Go through the above-mentioned drive link if any confusion arises.
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