About bricks

What is Bricks
A brick is building material used to make walls, pavements and other elements in masonry construction. Traditionally, the term brick referred to a unit composed of clay, but it is now used to denote any rectangular units laid in mortar.

TYPES OF BRICKS:

Bricks are one of the most useful building materials used in construction works. It is important to know the types of bricks for understanding the masonry work properly. The types of bricks depend on their quality, strength, making process, motivation behind their utilizing etc. In this article, we will discuss types of bricks used for different criteria.

The three main types of bricks

There are three general types of bricks - facing bricks, engineering bricks and common bricks. Learn more about them here.
Facing Bricks
Facing bricks are the most popular type of brick and have been the façade material of choice in the thousands of years, particularly in the housing market.
They are primarlily used for the external walls of a building and so are generally chosen for their aesthetic qualities.
Facing bricks are produced using different manufacturing techniques so they are available in a number of different types including softmud (stock bricks) and extruded (wirecut).
As well as their aesthetic qualities they must also be weather resistant.
Engineering Bricks
What Are 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. These bricks are used in specific projects and they can cost more than regular or traditional bricks.

Engineering bricks have high compressive strength and low water absorption. They are used for their physical characteristics and not their appearance.

They were traditionally used in civil engineering and are most suitable for applications where strength and resistance to frost attack and water are important.
Bricks are mainly classified into two general categories.

1. Unburnt Bricks & 2. Burnt Bricks.
   Types of Bricks Based on Quality
   These are 9.5” x 4.5” x 2.75” in size available in Bangladesh . They are made from good earth, free from saline deposits. They should be thoroughly burnt. They should be of good color. They should be of regular shape with square edges and parallel faces.

Depending on quality, bricks are three type –
• First class brick
• Second class brick, and
• Third class brick.
First class brick: These bricks are made from good quality raw materials. Color of first class brick is uniform. These are regular in size and shape and doesn’t absorb more than 15% water of its own dry weight when immersed in fresh water for 24 hours. The crushing strength of this type of brick should be 105 kg/cm2.
Second class brick: The quality of bricks of this type is little bit less from first class brick. Such as it can be slightly over burned. The size and shape can be slightly differ from standard. The crushing strength of this brick-type should be above 70 kg/cm2. These bricks don’t absorb more than 22% water of its own weight after 24 hours immersion in fresh water.
Third class brick: This type of brick isn’t uniform in size and shape. It can be over burnt or under burnt. It doesn’t absorb more than 25% water of its own weight when immersed 24 hours in fresh water. Crushing strength of this type is more than 30 kg/cm2.

Common Bricks
Despite their name, common bricks are actually the least common brick types in the UK. They tend to have lower compressive strengths than facing bricks or engineering bricks and are generally lower quality. There is also less focus put into a consistent appearance on common bricks.

Common bricks should not be used below ground and are generally used for internal brickwork only.

Characteristics of Good Bricks
It is always desirable to use the best quality brick in constructions. Therefore, the Characteristics of a good brick must be investigated. Generally good bricks possesses following properties-

• Bricks should be uniform in color, size and shape. Standard size of brick should be maintained.
• They should be sound and compact.
• They should be free from cracks and other flaws such as air bubbles, stone nodules etc. with sharp and square edges.
• Bricks should not absorb more than 1⁄5 of their own weight of water when immersed in water for 24 hours (15% to 20% of dry weight).
• The compressive strength of bricks should be in range of 2000 to 5000 psi (15 to 35 MPa).
• Salt attack hampers the durability of brick. The presence of excess soluble salts in brick also causes efflorescence. The percentage of soluble salts (sulphates of calcium, magnesium, sodium and potassium) should not exceed 2.5% in brunt bricks.
• Brick should not change in volume when wetted.
• Bricks should neither overburnt nor under-brunt.
• Generally, the weight per brick should be 6 lbs. and the unit weight should be less than 125 lbs. per cubic ft.
• The thermal conductivity of bricks should be low as it is desirable that the building built with them should be cool in summer and warm in winter.
• Bricks should be sound proof.
• Bricks should be non-inflammable and incombustible.
• Bricks should be free from lime pitting.
Uses of Brick
Brick plays very important role in the field of civil engineering construction. Bricks are used as an alternative of stones in construction purpose. Here some main uses of construction brick are given below.
• Construction of walls of any size
• Construction of floors
• Construction of arches and cornices
• Construction of brick retaining wall
• Making Khoa (Broken bricks of required size) to use as an aggregate in concrete
• Manufacture of surki (powdered bricks) to be used in lime plaster and lime concrete
Brick Tests Details - Quality Construction Work
List of Brick Tests
• Absorption test
• Compressive Strength Test (Crushing Strength Test)
• Efflorescence Test (Presence of Soluble Salts)
• Hardness Test
• Impact Test
• Dimension Tolerance Test
• Shape and Size
• Color Test
• Soundness Test
• Structure Test
Cost:
Because of the factors mentioned above. brickwork is cheaper compared to other two types of constructions:
Where bricks are not available locally and have to be transported from far-off distances, the locally available stone may give a cheaper construction.
Now Average price of Bangladesh is Tk.8500 – Tk.9500/ per Thousand
Why is Brick Construction so Popular?
There are many advantages when bricks are used as part of the construction. The following list presents some of the most common advantages when using bricks instead of other construction materials.
• Aesthetic - Bricks offer natural and a variety of colors, including various textures.
• Strength - Bricks offer excellent high compressive strength.
• Porosity - The ability to release and absorb moisture is one of the most important and useful properties of bricks, regulating temperatures and humidity inside structures.
• Fire Protection - When prepared properly a brick structure can give a fire protection maximum rating of 6 hours.
• Sound Attenuation - The brick sound insulation is normally 45 decibels for a 4.5 inches brick thickness and 50 decibels for a nine-inch thick brick.
• Insulation - Bricks can exhibit above normal thermal insulation when compared to other building materials. Bricks can help regulate and maintain constant interior temperatures of a structure due to their ability to absorb and slowly release heat. This way bricks can produce significant energy savings, more than 30% of energy saving when compared to wood.
• Wear Resistant - A brick is so strong, that its composition provides excellent wear resistance.
• Efflorescence - Efflorescence forms on concrete structures and surfaces when soluble salts dissolved in water are deposited and accumulated on surfaces forming a visible scum.
• Durability - Brick is extremely durable and perhaps is the most durable man-made structural building material so far.
Specifications of First class brickwork
• All of the bricks used should be of first class.
• See the characteristics of first class bricks .
• Soaking of bricks should be done by submerging in a tank before use.
• Soaking should be continue until the air bubbles are ceased.
• Soaking should be for a period of 12 hour before use.
Laying of first class brickwork
• Bricks should be laid in English bond unless otherwise specified.
• Every course of brick should be horizontal.
• Wall should be truly in plumb.
• Vertical joints of consecutive brick layer should not come on each other.
• Vertical joints of alternate brick layer should come directly over one another.
• Closers should be of clean cut bricks.
• Closers should be placed at the end of the walls but not at the other edge.
• Best shaped brick should be used for face work.
• Mortar joints should not exceed 6 mm or 0.5 inch in thickness.
• Joints should be fully filled with mortar.
• Bricks should be laid with frogs upwards except in the top brick layer.
• In the top course of brickwork, frog should be laid downward.
• Brickwork should be done for 1 meter or 3 feet height at a time.
• When one part of the wall has to be delayed then stepping should be done at an angle of 45 degree.
• Projections where made should not be more than 1/4th of the brick in one course.
• All joints should be raked and faces of wall should be cleaned at the end of every day’s work.
Curing of First class brickwork
• Brickwork should be kept wet for the period of at least 10 days.
• Top of the walls should be flooded with water at the end of the days work by making small weak mortar edging to contain at least 2.5 cm or 1 inch deep water.
Facing Bricks

Rough side of wall