Bricks : Its Types, Qualities and Construction Standards.

Introduction

Bricks are a major construction material used in wall construction, along with binding materials such as mortar or a mixture of cement, sand, and water. Bricks are typically made from clay and traditionally dried initially through sunlight and finally in a kiln.

1. Types of Bricks

• Burnt Clay Bricks: Traditional bricks made by sun-drying or firing clay.
• Common Bricks: Standard bricks used for general construction, typically made of clay.
• Cored Bricks: Bricks with indentations or cores, which reduce weight and provide insulation.
• Engineering Bricks: High-density bricks with excellent strength and low water absorption, suitable for load-bearing structures.
• Facing Bricks: Bricks designed for facing or visible surfaces, often chosen for their aesthetic appeal.
• Fire Bricks: Highly heat-resistant bricks used in fireplaces, ovens, and other high-temperature applications.
• Fly Ash Bricks: Bricks made from fly ash, a waste material from coal combustion, often used for environmental reasons.
• Glazed Bricks: Bricks with a glossy or glazed surface, often used for decorative purposes.
• Hollow Bricks: Bricks with hollow cores, providing better insulation and reducing weight.
• Hydraulic Bricks: Bricks made using a hydraulic press, resulting in a dense and strong product.
• Lightweight Bricks: Autoclaved Aerated Concrete blocks with low density, offering good insulation properties.
• Paver Bricks: Thick, strong bricks used for paving outdoor areas like driveways and walkways.
• Perforated Bricks: Bricks with holes to reduce weight and improve insulation properties.
• Permeable Bricks: Bricks designed to allow water to pass through, promoting drainage in pavements.
• Pressed Bricks: Bricks formed by pressing the clay into molds, resulting in a smooth and uniform finish.
• Refractory Bricks: Bricks designed to withstand high temperatures, commonly used in furnaces and kilns.
• Sand Lime Bricks: Bricks made from sand, lime, and water, cured by steam.
• Solid Bricks: Bricks without any perforations or holes, offering high strength and durability.
• Wire cut Bricks: Bricks that are wire-cut from a column of clay, resulting in smooth and precise faces.

2. Standard Size of Bricks

• Length: 9 inches (229 mm) - Width: 4.5 inches (115 mm) - Height: 3 inches (75 mm)
• Length: 8 inches (203 mm) - Width: 3 5/8 inches (92 mm) - Height: 2 1/4 inches (57 mm)

3. Classes/Qualities of Bricks

• 1st Class Bricks:
  • High-quality bricks with uniform shape and size.
  • Compression strength of 1400 psi to 1600 psi.
  • Sharp edges, smooth surfaces without cracks or deformities.
  • Produce a clear ringing sound when struck together.
  • Uniform color, thoroughly burnt during firing.
  • Used in superior construction work where aesthetics and strength are crucial.
• 2nd Class Bricks:
  • Medium-quality bricks with slight irregularities in shape and size.
  • Compression strength of 1000 psi to 1400 psi.
  • Minor surface cracks that do not significantly affect strength.
  • Produce a dull sound when struck together.
  • Variations in color, partially burnt during firing.
  • Suitable for walls where appearance is not a primary concern.
• 3rd Class Bricks:
  • Lowest quality bricks, generally not used in load-bearing structures.
  • Compression strength of 900 psi to 1000 psi.
  • Irregular shapes, varying sizes, numerous cracks.
  • Produce a dull sound and may break when struck together.
  • Uneven coloring, often under-burnt during firing.
  • Typically used in non-structural applications.

Characteristics of Good Quality Bricks

• Bricks shall be well-burnt, of uniform color, regular in shape and size with square corners & parallel faces.
• Should emit a clear ringing sound when struck.
• Maximum limit of water absorption should not be more than 15%-18% of brick's own weight.

Construction Requirements

• All burnt bricks to be thoroughly soaked in water, before being laid in CM. Burnt bricks, built in mud mortar, will only be dipped in water before use. The joints of brickwork shall not be less than 6 mm or more than 10 mm in thickness.
• All joints to be well flushed up at every course. The walls shall be carried up regularly, not leaving any part more than one meter (1M) lower than another, unless special circumstances render this impracticable.
• Any wall left at different level to be raked back, courses be properly leveled, jambs and other angles plumbed as the work proceeds.
• All brickwork to be built in English bond unless otherwise specified. No half brick (bats) to be used, except where necessary to complete the bond.
• External facing be of sound hard bricks of good shape and uniform color with square and sharp edges, selected from stacks, deposited on site.
• Joints of brickwork will be struck, cleaned and the mortar pressed while the brickwork proceeds, using additional mortar if required. Raking out joints will NOT be done.
• Pointing the brickwork will be a separate process, including raking out joints and using different mortar from that of brickwork mortar. Pointing will NOT be done in the same mortar.
• The joints on faces, which are to be plastered or pointed, should be raked 10mm deep while the mortar is green, but not later than 24 hours after the brickwork is done.
• The pointing or striking out joints will normally be adopted as given below:
• Flush pointing with CM (cement mortar) be used on both faces of walls built in mud.
• Weather struck joints/pointing will generally be adopted for external work where the walls are not plastered.
• Recessed joints/pointing will generally be adopted for pillars, fireplaces, or other ornamental work/faces, required both internally and externally, where so ordered.
• Tuck-pointing will be done on surfaces, specially ordered by the Engineer-in-Charge.
• All new work in CM will be kept watered and damp for such periods as directed, not exceeding 14 days, and where it is to be built on old work, it will be kept watered for 2 days beforehand.

Conclusion

To summarize, when using bricks as a construction material, I suggest must use good-quality bricks in the superstructure to achieve the desired façade of the structure. Construction requirements should also be taken into consideration.