Difference: Fat Lime and Hydraulic Lime | Materials | Engineering

The upcoming discussion will update you about the difference between fat lime and hydraulic lime.

There are mainly two varieties of limes, namely, fat lime and hydraulic lime.

Difference # Fat Lime:

1. Composition:

It is obtained from comparatively pure carbonate of lime containing only 5 per cent of clayey impurities.

2. Slaking Action:

It slakes vigorously. Its volume is increased to about 2 to 2½ times the volume of quick lime. The slaking is accompanied by sound and heat.

3. Setting Action:

It sets slowly in presence of air. It absorbs carbon dioxide from atmosphere and forms calcium carbonate.

4. Hydraulicity:

It does not possess hydraulic property.

5. Colour:

It is perfectly white in colour.

6. Strength:

It is not very strong. Hence it cannot be used where strength is required.

7. Uses:

It is used for plastering, white­washing, etc. and for preparing mortar with sand or surkhi.

Difference # Hydraulic Lime:

1. Composition:

It is obtained from lime stones containing clay to the extent of about 5 to 30 per cent and some amount of ferrous oxide.

2. Slaking Action:

It slakes slowly. Its volume is slightly increased. The slaking is not accompanied by sound or heat.

3. Setting Action:

It sets under water. It combines with water and forms crystals of hydrated tricalcium aluminate and dicalcium silicate.

4. Hydraulicity:

It possesses hydraulic property.

5. Colour:

Its colour is not as white as fat lime.

6. Strength:

It is strong and can therefore be adopted where strength is required.

7. Uses:

It is used for preparing mortar for thick walls, damp places, etc. Extreme care is required to prepare mortar of this lime for plaster work.