NTS STUDY

Alternatives to Bricks & types

As bricks are made by excavating clay, the availability of good quality brick-earth is decreasing while the demand for construction grows. Therefore, it has become necessary to produce bricks from industrial waste and other raw materials. The currently available alternatives are:

• Fly Ash Bricks: These are made from fly ash, which is a waste product obtained from burning coal or lignite in industries, especially power plants. Lime or cement is added to provide the necessary strength. The Government of India encourages this use of waste products by providing concessions for their manufacture.

• Sandlime or Calcium Silicate Bricks: These are manufactured from sand, lime, and water (with added color if needed) by autoclaving them with high-pressure steam in special chambers. Due to high energy costs, they are not yet popular in India.

• Cement and Concrete Blocks: These are also used as effective alternatives to traditional clay bricks.

Classification of Bricks

Bricks can be classified in three ways based on their use, physical requirements, or Indian Standard (IS) specifications:

(a) According to Usage

Bricks are sometimes broadly categorized by how they are used:

• Common Bricks: For general construction work.

• Engineering Bricks: Special bricks designed to carry heavy loads.

• Facing Bricks: Used on the exterior of walls for a better appearance.

• Fire Bricks: Designed to withstand high temperatures.

• Special Shapes: Bricks manufactured in specific dimensions for unique purposes.

(b) According to General Physical Requirements

In some specifications, clay bricks are classified as Class I, Class II, and Class III based on their physical properties:

• These classes differ primarily in their water absorption properties.

• A good quality brick should not disintegrate even after being submerged in water for a long time; such disintegration indicates a lack of proper burning.

(c) I.S. Classification of Bricks

• IS 3102-1971: The "Classification of Burnt Clay Solid Bricks" standard classifies bricks according to the strength provided in the IS tables.