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Questions and Answers
Steel moulds are more ______ than wooden moulds.
Steel moulds are more ______ than wooden moulds.
durable
Ground moulded bricks are also called ______ moulded bricks.
Ground moulded bricks are also called ______ moulded bricks.
sand
A brick moulder can mould about ______ bricks per day.
A brick moulder can mould about ______ bricks per day.
750
Machine moulded bricks are usually ______ cut and pressed bricks.
Machine moulded bricks are usually ______ cut and pressed bricks.
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Plastic clay machines have a rectangular opening equal to the ______ of the bricks.
Plastic clay machines have a rectangular opening equal to the ______ of the bricks.
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In dry clay machines, strong clay is first converted into ______ form.
In dry clay machines, strong clay is first converted into ______ form.
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During the drying process, bricks are placed along their ______ to speed up drying.
During the drying process, bricks are placed along their ______ to speed up drying.
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The drying period for bricks usually varies from ______ to 14 days.
The drying period for bricks usually varies from ______ to 14 days.
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The clay used for preparing bricks should be cleaned of stones, pebbles, and ______.
The clay used for preparing bricks should be cleaned of stones, pebbles, and ______.
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Subjecting the soil to exposure to weather elements like rain, heat from the sun, and snow is known as ______.
Subjecting the soil to exposure to weather elements like rain, heat from the sun, and snow is known as ______.
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During the ______ process, water is added to the clay to achieve a proper degree of hardness.
During the ______ process, water is added to the clay to achieve a proper degree of hardness.
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The depth mark placed over the surface of the brick during moulding is termed the ______ mark.
The depth mark placed over the surface of the brick during moulding is termed the ______ mark.
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Bricks can be moulded using either hand moulding or ______ moulding.
Bricks can be moulded using either hand moulding or ______ moulding.
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Wooden moulds for brick making should be prepared from well-seasoned ______.
Wooden moulds for brick making should be prepared from well-seasoned ______.
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Steel moulds are typically made from steel plates or ______.
Steel moulds are typically made from steel plates or ______.
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Blending involves making the clay loose and adding any ______ that needs to be mixed with it.
Blending involves making the clay loose and adding any ______ that needs to be mixed with it.
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The moulded bricks are dried to remove maximum ______ from the brick.
The moulded bricks are dried to remove maximum ______ from the brick.
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Burning impacts the strength and ______ of the bricks.
Burning impacts the strength and ______ of the bricks.
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The burning of bricks occurs at temperatures of around ______ °C.
The burning of bricks occurs at temperatures of around ______ °C.
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During the Vitrification stage, the goal is to convert the mass into a ______-like substance.
During the Vitrification stage, the goal is to convert the mass into a ______-like substance.
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Burning of bricks in clamps involves alternate layers of raw bricks and ______.
Burning of bricks in clamps involves alternate layers of raw bricks and ______.
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Kilns are large sized ovens used for burning bricks, with a fire period of ______ to 60 hours.
Kilns are large sized ovens used for burning bricks, with a fire period of ______ to 60 hours.
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The total height of a clamp used for burning bricks can reach up to ______ meters.
The total height of a clamp used for burning bricks can reach up to ______ meters.
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Intermittent kilns allow only one process to take place at a ______.
Intermittent kilns allow only one process to take place at a ______.
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Study Notes
Construction Materials and Equipment (CENG-2081)
- Course is about construction materials and equipment.
- Specific focus on stone-bricks-concrete blocks.
Chapter 1: Stone-Bricks-Concrete Blocks
- Introduces different types of construction materials.
- Starts with a detailed study of bricks.
Bricks
- Bricks are a popular building material because they are cheap, durable, and easy to handle and work with.
- Bricks are used in exterior and interior walls, partitions, piers, footings, and other load-bearing structures.
Introduction to Bricks
- Bricks are rectangular.
- They come in various sizes, that are convenient for use. (19x9x9 cm, 19x9x4 cm)
- Brick materials can include burnt clay, mixture of sand and lime, or Portland cement concrete..
- Availability and cost-effectiveness make clay bricks a common choice.
Size of a Brick
- Standard size: 19cm x 9cm x 9cm or 19cm x 9cm x 4cm.
- When placed in masonry with mortar, a standard brick's overall size becomes 20cm x 10cm x 10cm (field bricks).
- The dimensions of bricks are relevant for construction work.
- Length of brick = 2 x width of brick + thickness of mortar. Height of brick = width of brick.
- Indent, called frog (depth 1-2cm) on the brick.
Composition of Brick
- Key constituents are silica (50-60%), alumina (20-30%), lime (4-5%), Iron oxide (5-6%), and Magnesia (1%).
- These elements are essential for making quality bricks.
Manufacturing of Bricks
- Consists of 4 steps:
- Preparation of Brick Earth
- Moulding
- Drying
- Burning
- (1) Preparation of Brick Earth*
- Unsoiling: Removal of the top 200mm of soil.
- Digging: Extraction of clay from the ground. The clay is levelled and prepared in heaps (60cm-120cm height).
- Cleaning: Removal of stones, pebbles, or other impurities from the clay. Washing and screening are used if needed.
- Weathering: The clay is exposed to the weather (rain, sun, wind) for a few weeks/full season. This process is known as weathering.
- Blending: Mixing/loosening clay for proper combining of ingredients and achieving uniformity and removing impurities.
- Tempering: Process to bring clay to required hardness and preparing it for moulding, done via adding water to the clay (via feet of men or cattle).
- (2) Moulding*
- The process of shaping the brick using moulds.
- Hand moulding: Using manpower to shape bricks. Different types exist (Ground, Table).
- Machine moulding: Utilizing machines to produce bricks (Plastic clay and Dry clay machines).
- Types of moulds: Wooden moulds and Steel moulds
- (3) Drying*
- This is a process where damp bricks or green bricks are dried before burning to prevent cracking and distortions.
- Duration (7–14 days).
- Bricks are placed along the edges, not the face during drying to speed the process.
- (4) Burning*
- Brick burning is done in specific temperatures (1100°C ) making the brick more dense.
- Over burnt/under burnt bricks can lead to improper quality and results.
- Burning occurs in 3 stages (Dehydration/Water smoking stage, Oxidation period, Vitrification).
- Different techniques exist (Clamps and Kilns).
- Clamp burning: Trapezoidal shape with ends raised at 15 degrees.
- Kiln burning: Large ovens used to burn bricks.
Classification of Bricks
- Unburnt/Sundried Bricks: temporary, used in places with less rainfall.
- Burnt Bricks: further categorized into 4 grades (including first class, second class, third class, and fourth class) based on quality.
- First class: table moulded, sharp edges, used for permanent work.
- Second class: ground moulded and burnt, may have irregular edges, used for walls plastered later.
- Third class: ground moulded and burnt in clamps, used for temporary/unimportant, less rainfall.
- Fourth class: overburnt bricks, irregular shape and dark colour. Used in concrete foundations, floors and roads as aggregates.
Qualities of a Good Brick
- Free from cracks and sharp edges.
- Uniform shape and standard size.
- Sound when struck together
- Compact.
- Minimum water absorption when soaked for 24 hours (1st class max 20%, 2nd class max 22% by weight).
- No impression when scratched with a fingernail.
- Low thermal conductivity, good sound proof properties.
- Dropped from 1m and won't break in half.
- No white salts when dried in the shade
- High crushing strength (>55 kg/cm2)
Tests on Bricks
- Compressive strength test: Determining the strength of the bricks using machines by recording pressure needed to break.
- Water absorption test: Measuring the percentage of water absorbed (max 20% for 1st class.
- Efflorescence test: Identifying presence of impurities (alkalies.)
- Hardness test: Assessing strength against abrasions.
- Soundness test: Detecting soundness by checking the clear metallic ringing sound.
- Structure test: Detecting the quality of bricks on broken faces (cracks, voids).
Concrete Blocks
- Concrete is a composite material created by mixing cement, aggregate and water.
- Masonry unit made from a different material mixture.
- Concrete blocks are produced by machines (Block making machines).
Classification of Concrete Blocks
- Solid blocks: No cavities, voids less than 25%.
- Cellular blocks: One or more voids.
- Hollow blocks: Common type, voids up to 50% (Types include Stretcher, Corner, Pillar, Jamb, Partition, Lintel, Brick, Bull nose).
Advantages of Concrete Blocks
- Lightweight (using lightweight aggregate).
- Less mortar needed.
- Quicker construction.
- High seismic resistance (can fill voids with steel bars).
- Good thermal insulation.
- Use for electrical and plumbing installations.
Materials for Concrete Blocks
- Cement: OPC, Portland blast furnace slag, sulfate resisting.
- Aggregate: Coarse aggregate (Max. particle size 13 mm). Rounded or angular particles have differing affects (flow and strength).
- Water: Enables chemical reactions. Lubricates mixture.
Production Process
- Proportioning: Measuring suitable amounts of raw materials.
- Mixing: Combining raw materials into homogeneous mix.
- Compacting: Consolidating mix in molds (using machines like Egg-laying/Auto stationary).
- Curing: Maintaining moisture and temperature (7–14 days) for concrete to reach the desired strength.
Tests on Concrete Masonry Blocks
- Various tests to meet all the requirements (Dimension measurement; Compressive strength.)
- Dimension measurement: Measuring length, width and height.
- Compressive strength test: Taking average max load in Newton's divided by the gross cross section area in square millimetre. Minimum required strength for different classes of concrete blocks.
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Description
Test your knowledge on the methods and materials involved in brick manufacturing. From mould types to drying processes, this quiz covers various aspects of brick production. See how well you understand the intricacies of creating bricks!
