What is Lime in Construction? Types?

 

Lime is an inorganic material composed primarily of calcium oxides and hydroxides. It is also the name for calcium oxide which occurs as a product of coal-seam fires and in altered limestone xenoliths in volcanic ejecta. The word lime originates with its earliest use as building mortar and has the sense of sticking or adhering.

TYPES OF LIMES USED IN CONSTRUCTION

 

Different types of limes used in construction are Quick Lime, Slaked Lime, Fat Lime and Hydraulic Lime. They are obtained by the process of calcination of natural limestone over a temperature of 900-degree Celsius. Every form of lime is highly versatile and is used in environmental, construction, chemical and metallurgical industries.

 

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:

 

         I.            Class A – Eminently hydraulic

       II.            Class B – Semi Hydraulic

     III.            Class C – Non-hydraulic (or Fat lime)