Q.
a) What is a clay brick? Explain the types of clay bricks. (12 marks)
(25 marks, 2012 Q5)
A.
From Wikipedia, ... "A brick is a block or a single unit of a kneaded clay-bearing soil, sand and lime, or concrete material, fire hardened or air dried, used in masonry construction. Lightweight bricks (also called lightweight blocks) are made from expanded clay aggregate.
Fired brick are the most numerous type and are laid in courses and numerous patterns known as bonds, collectively known asbrickwork, and may be laid in various kinds of mortar to hold the bricks together to make a durable structure.
Brick are produced in numerous types, materials, and sizes which vary with region and time period, and are produced in bulk quantities. Two most basic categories of brick are fired and non-fired brick.
Fired brick are one of the longest lasting and strongest building materials sometimes referred to as artificial stone and have been used since circa 5000 BC.
Air dried bricks have a history older than fired bricks, are known by the synonyms mud brick and adobe, and have an additional ingredient of a mechanicalbinder such as straw."
Types of clay bricks:
- Common Burnt Clay Bricks
- Sand Lime Bricks (Calcium Silicate Bricks)
- Engineering Bricks
- Concrete Bricks
- Fly ash Clay Bricks
Common Burnt Clay Bricks
Common burnt clay bricks are formed by pressing in molds. Then these bricks are dried and fired in a kiln. Common burnt clay bricks are used in general work with no special attractive appearances. When these bricks are used in walls, they require plastering or rendering.
Sand Lime Bricks
Sand lime bricks are made by mixing sand, fly ash and lime followed by a chemical process during wet mixing. The mix is then molded under pressure forming the brick. These bricks can offer advantages over clay bricks such as:
Their color appearance is grey instead of the regular reddish color.
Their shape is uniform and presents a smoother finish that doesn’t require plastering.
These bricks offer excellent strength as a load-bearing member.
Engineering Bricks
Engineering bricks are bricks manufactured at extremely high temperatures, forming a dense and strong brick, allowing the brick to limit strength and water absorption. Engineering bricks offer excellent load bearing capacity damp-proof characteristics and chemical resisting properties.
Concrete Bricks
Concrete bricks are made from solid concrete. Concrete bricks are usually placed in facades, fences, and provide an excellent aesthetic presence. These bricks can be manufactured to provide different colors as pigmented during its production.
Fly Ash Clay Bricks
Fly ash clay bricks are manufactured with clay and fly ash, at about 1,000 degrees C. Some studies have shown that these bricks tend to fail poor produce pop-outs, when bricks come into contact with moisture and water, causing the bricks to expand.
Ref:
http://en.wikipedia.org/wiki/Brick
http://construction.about.com/od/Masonry/a/Bricks-Bricks-Types.htm