Types of Limes
Different types of limes are used for building construction. It is not generally found in the free state. Lime is a product which is obtained by burning lime stone, a raw material, found in lime stone hills or lime stone boulders in the beds of old river, kankar found below ground level, or shells of sea animals.
Uses of Building Lime
Lime in building industry is used for various purposes such as
- A matrix for lime concrete used in building foundations and filling where early setting is not required,
- For preparing mortar for bedding bricks and stones in masonry works,
- As a cementing material in plaster for covering walls and pointing in preserving joints, and
- For white washing and colour washing.
4 Types of Limes
1. Quick lime
It is also known as caustic lime. It is obtained by calcination (i.e. heating to redness) of comparatively pure lime stone. It is amorphous in nature, highly caustic and possesses great affinity to moisture.
2. Slaked lime
It is also known as hydrate of lime. It is obtained by slaking (i.e. chemical combination of quick lime with water) of quick lime. It is ordinary pure lime, in white powder form, available in market. It has got the tendency of absorbing carbonic acid from the atmosphere in presence of water.
3. Fat lime
It is also known as high calcium lime or pure lime or rich lime or white lime. It is popularly known as fat lime as it slakes vigorously and its volume is increased to about 2 to 2.5 times that of quick lime. This lime is used for various purposes as white washing, plastering of walls, as lime mortar with sand for pointing in masonry work, as a lime mortar with surkhi for thick masonry walls, foundations, etc.
4. Hydraulic lime
It is also known as water lime. This lime contains clay and some amount of ferrous oxide. It sets under water and hence also known as water lime. Depending upon the percentage of clay IS has divided hydraulic lime in three classes namely:
- Class A – Eminently hydraulic
- Class B – Semi Hydraulic
- Class C – Non-hydraulic (or Fat lime)
Class A – Eminently hydraulic
This lime contains about 25% clay content and sets readily under wwater within a day or so. This lime slakes with difficulty. The mortar and lime concrete prepared from this lime is very useful for construction under water or in damp places.
Class B – Semi Hydraulic
Semi-hydraulic lime contains about 15% clay content and sets under water at a slower rate within a week or so. The mortar and concrete prepared from this lime is strong and used for superior type of masonry work.
Class C – Non-hydraulic (or Fat lime)
This lime contains about 7.5% of clay content and is prepared from pure lime stone. This slakes vigorously within few minutes but does not set under water. This is used for white washing and colour washing.
Also Read: Setting Time Test of Building Lime