Civil Engineering Question :Describe the procedure to list the soundness of cement. Name the constituents causing soundness.
It is most needed that cement after setting should not sustain any appreciable change in volume. Some cement have been found to undergo a large expansion after setting causing disruption of the set and hardened mass.
The presence of excess of lime than that could be combined with acidic-oxide at the kiln is the main cause of of unsoundness in cement. Too high a proportion of Magnesium content or Calcium sulphate content may cause unsoundness of cement.
Unsoundness in cement does not come to surface for a considerable period of time..
The Le-chatellier test finds out unsoundness due to free lime only. Cement having a Magnesia content of more than 3% shall be tested for soundness by• autoclave test. Test process:—A heat cement specimen is placed in a standard autoclave and a steam pressure, inside the autoclave is raised in such a rate as to bring the gauge pressure bof the steam 21 kg/cm2 in l—1.25 m . fromthe time the heat is turned-on.
The autoclave is cooled and length measured again. A cement having calcium. sulphate can be easily tested by chemical analysis.
It is most needed that cement after setting should not sustain any appreciable change in volume. Some cement have been found to undergo a large expansion after setting causing disruption of the set and hardened mass.
The presence of excess of lime than that could be combined with acidic-oxide at the kiln is the main cause of of unsoundness in cement. Too high a proportion of Magnesium content or Calcium sulphate content may cause unsoundness of cement.
Unsoundness in cement does not come to surface for a considerable period of time..
The Le-chatellier test finds out unsoundness due to free lime only. Cement having a Magnesia content of more than 3% shall be tested for soundness by• autoclave test. Test process:—A heat cement specimen is placed in a standard autoclave and a steam pressure, inside the autoclave is raised in such a rate as to bring the gauge pressure bof the steam 21 kg/cm2 in l—1.25 m . fromthe time the heat is turned-on.
The autoclave is cooled and length measured again. A cement having calcium. sulphate can be easily tested by chemical analysis.
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