Different types of limes are used for building construction. It is not usually found in the free state. Lime is a product obtained by burning limestone, a raw material, found in limestone hills or limestone rocks in old river beds, pebbles found under the ground, or marine animals. The balls
In the construction industry, lime is used for various purposes such as
- a matrix for lime concrete used in the construction of foundations and where initial setting is not required,
- For preparing mortar for bedding of bricks and stones in masonry works,
- as a cementing material in plaster to cover walls and to serve to protect joints, and
- For white washing and color washing.
1. quick lime
It is also known as Caustic Lime. It is obtained by calcination (i.e. heating to redness) of comparatively pure limestone. It is amorphous in nature, highly caustic and has a very good affinity for moisture.
2. slaked lime
It is also known as lime hydrate. It is obtained by slaking of quicklime (ie chemical combination of quicklime with water). It is simple pure lime available in the market in the form of white powder. It has a tendency to absorb carbonic acid from the atmosphere in the presence of water.
3. coarse lime
It is also known as high calcium lime or pure lime or rich lime or white lime. It is known as coarse lime because it is hard to cast and increases in volume by about 2 to 2.5 times the amount of coarse lime. This lime is used for various purposes such as whitewashing, plastering of walls, as lime mortar with sand for pointing in masonry work, lime with sieves for thick masonry walls, foundations etc. as a mortar.
4. hydraulic lime
It is also known as water lime. This lime contains clay and some amount of ferrous oxide. It freezes under water and hence it is also called water lime. On the basis of soil percentage, IS has divided hydraulic lime into three classes:
- Class A – Eminent Hydraulic
- Class B – Semi Hydraulic
- Class C – Non-hydraulic (or rough lime)
Class A – Eminent Hydraulic
This lime has about 25% clay content and easily sets under water within a day or so. This lime is very difficult to cast. 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 has about 15% clay content and sets slowly under water within a week or so. Mortar and concrete prepared from this lime is stronger and is used for better types of masonry work.
Class C – Non-hydraulic (or rough lime)
This lime has about 7.5% clay content and is prepared from pure limestone. It drops hard within a few minutes but does not freeze under water. It is used for whitening and color washing.
Also read: Setting Time Test Of Building Lime