Understanding the Key Differences Between Fat Lime and Hydraulic Lime

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.