Building Materials

Lime and Limestone Characteristics and Uses

Lime is used for construction works since ancient times lime is also used to manufacture cement and other construction products.

 

Depending upon the calcium Oxide content lime may be of three types.

  • FAT Lime
  • Hydraulic Lime and
  • Poor Lime

Quick lime contains about 95% calcium oxide. Quick lime is obtained from stone containing Calcium Carbonate the stones are heated to drive out Carbonate as CO2 leaving Calcium Oxide. The burning is done at kiln and is known as Calcination After slaking the quick lime increases its volume 2 to 2.5 times and its known as Fat lime.

 

Hydraulic Lime is obtained from burning limestone containing lot of clay material along with the calcium carbonate. This lime has setting property that means it can set lime cement and that is known as hydraulicity. It can set under water. Setting property depends upon the amount of clay and its property.

Its further subdivided into three category-

Feebly Hydraulic Lime – Less than 15% Silica and Alumina

Moderately Hydraulic Lime – 25 to 30%

 

Poor Lime – The lime which contains more than 30 % clay material and slakes very slowly and does not dissolve in water. This lime has setting property but it set and hardens very slowly.

 

Lime is classified according to IS 1973 as various classes namely –

Class A – Eminently Haudraulic lime

Class –B Semi Hydraulic lime

Class C – Fat Lime

Class D – Magnesium Lime

Class E – Kankar Lime

Properties of Lime –

  1. Lime is easily workable.
  2. Lime has good plastic properties.
  • It can withstand moisture.
  1. It imparts good strength if used as mortar.
  2. Masonry lime is more durable due to its low shrinkage.
  3. Good adhering properties with stone and brick similar to cement.

Uses of Lime –

There are a lot of use of lime in construction industry following are the few examples-

  • Limestone Extensively used for manufacturing of cement.
  • Its used as binding material in mortar and in cement.
  • Extensively used as plastering material.
  • Sometimes used as an aggregate.
  • Used fro base coat and distempering of wall.
  • Used as flux material in many industry.
  • Lime is used for soil stabilization.
  • It is used to improve soil property for agricultural purposes (for controlling pH of soil).
  • Used in fish culture.
  • Used in sewage treatment process.
  • Used in glass manufacturing.

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