Brick

From ArticleWorld

A Brick is the term used for a rectangular block of clay baked by the sun or in a kiln; used as a building or paving material. Bricks are formed with wet clay and molded while soft and then after first being allowed to dry in the sun are fired in kilns to harden and become, literally, the building blocks of constructions. Bricks may be made out of clay as well as shale. The effect of the heat on the iron in the clay gives a red color while an addition of lime or magnesia produces a yellow color. Another name for bricks in technical parlance is compressed earth blocks (CEB).

History

The earliest bricks were used by the people of the Near East and India more than 5000 years ago. Bricks have also been discovered as being used by the Tigris-Euphrates civilizations and also for the ancient Sumerian structures. In the ruins of the, more than 3500 years old, Indus Valley civilizations small brick pieces have been discovered. They bear striking similarities to the bricks of today and were used to build the houses of Mohan jodaro and Harappan civilizations. The Romans used bricks that they fired even while far from home by carrying mobile kilns.

Types and proportion

The bricks of the Indus Valley civilization were made in the proportion of 4:2:1 i.e. the width or the depth of the brick was half its length, while the height of the brick was kept at one-fourth the length of the brick. This proportion is even in the modern technology considered the best for optimal strength and binding.

US bricks are made to the proportion of 8 x 4 x 2.25 inches while the bricks in England are of the proportion of 215 x 102.5 x 65 millimeters. Addition of salt to the bricks during the firing process is a popular way to add embellishment and extra glaze to the brick and is known as salt-glazing.

Uses

Apart from being used as the basis of building constructions, bricks are used to pave roads (generally pavements) and paths. In glass factories and metallurgical industries they are used to line furnaces, which are made using silica and magnesia to lend extra thermal shock resistance to the bricks.