Comparison of Red Bricks vs AAC Blocks vs Fly Ash Bricks vs Solid Concrete Blocks vs CLC Blocks

Red bricks are not only one of the oldest but also the most extensively used building materials worldwide. Still they are the most popular and leading construction material particularly in developing countries because they are cheap, durable and easy to handle and to work with.

Red bricks are primarily made from clay which is obtained from topsoil of the earth’s surface. On continuous production of red bricks, the fertile topsoil is lost and hence the land available for agriculture decreases. Hence red bricks are not considered environment friendly.

They also emit carbon dioxide during the production. Research and innovations has lead to the invention of alternative masonry units which are environment friendly. AAC blocks, fly ash bricks, solid concrete blocks, and CLC blocks are relatively new building materials which are now used as an alternative to red bricks.

While comparing red bricks vs AAC blocks vs fly ash bricks vs solid concrete blocks vs CLC blocks, there arises confusion in selection of masonry units for constructing a house. Here we have given comparison between red bricks, AAC blocks, fly ash bricks, solid concrete blocks, and CLC blocks, to help you make the right choice.

Also Read: Various Shapes of Brick used in Construction
Courtesy - Shutterstock, Flickr, Financial Tribune, Asanduff Construction

01. General

Red Bricks

• A Red brick is a single unit of a ceramic i.e. clay material used in masonry construction.

AAC Blocks

• AAC Blocks are lightweight building blocks cut into masonry blocks or formed larger planks and panels.

Fly ash Bricks

• Fly ash bricks are environment friendly bricks which are made using fly ash. They are also called pulverised fuel ash – lime bricks.

Solid Concrete Blocks

• Solid concrete blocks are precast concrete blocks which are primarily made from cement and fine aggregates.

CLC Blocks

• CLC blocks are made from cellular lightweight concrete (CLC) or foam concrete.

02. Raw Materials

Red Bricks

• Red bricks are made by mixture of clay (alumina), sand, lime, iron oxide and magnesia. Sand from locally available natural soil is used for production of bricks.

AAC Blocks

• AAC blocks are made from the mixture of cement, lime, gypsum and an aeration agent. Sometimes a little amount of fly ash is also added in the mixture.

Fly ash Bricks

Fly ash bricks are made from the mixture of fly ash, cement, sand, lime, and gypsum.

Solid Concrete Blocks

Solid concrete blocks are made of a mixture of Portland cement, water, sand and gravel. Sometimes fly ash is used as fine aggregate.

CLC Blocks

CLC Blocks are made from cement, fly ash slurry, water and a foaming agent.

03. Uses

Red Bricks

Red bricks are strong, hard, and durable, therefore they are used as a structural material in different structures such as buildings, bridges, foundations, arches and cornices, and pavements.

Red bricks are also used for aesthetic purposes such as facing bricks, architectural purposes, exposed practice work and in landscaping.

AAC Blocks

AAC Blocks can be used to build internal and external walls of a framed structure. AAC blocks are also used in load bearing structures.

Fly ash Bricks

Fly ash bricks are strong and durable bricks which are used as an alternative to clay bricks. They can be used in masonry construction as well as for other uses in which red bricks are used.

Solid Concrete Blocks

Solid Concrete Blocks are used for both load-bearing and non-load bearing walls, partitions and-panel walls, as backing for other types of facing material, for piers, for retaining walls, garden walls, chimneys and fire places.

CLC Blocks

CLC blocks are used to build walls of low cost housing. They are also used for structures which require good sound insulation properties.

04. Properties

(a) Sizes Available in Market

Red Bricks

Standard modular sizes are:

• 190x90x90mm
• 190x90x40mm

Standard non modular sizes are:

• 230x110x70
• 230x110x30

These sizes are more popular in India.

AAC Blocks

Standard sizes available in the market:

• Length: 400, 500 or 600 mm.
• Height: 200, 250 or 300 mm.
• Width: 100, 150, 200 or 250 mm.

However, it defers from manufacturer to manufacturer.

Fly ash Bricks

Standard modular sizes are:

• 190x90x90 mm
• 190x90x40 mm

Standard non modular sizes are:

• 230x110x70 mm
• 230x110x30 mm

These sizes are more popular in India.

Solid Concrete Blocks

Standard sizes available in the market:

• Length: 400, 500 or 600 mm.
• Height: 200 or 100 mm.
• Width: 50, 75, 100, 150, 200, 250 or 300 mm.

However, it defers from manufacturer to manufacturer.

CLC Blocks

Standard sizes available in the market:

• Length: 400, 500 or 600 mm.
• Height: 200, 250 or 300 mm.
• Width: 100, 150, 200 or 250 mm.

However, it defers from manufacturer to manufacturer.

(b) Dry Density

Red Bricks

• 1600 – 1920 kg/m3, varies according to the class of bricks.

AAC Blocks

• 451 – 1000 kg/m3, varies according to the grade of blocks.

Fly ash Bricks

• 1700 – 1850 kg/m3, varies according to the class of bricks.

Solid Concrete Blocks

• 1800 – 2500 kg/m3, varies according to the grade of blocks.

CLC Blocks

• 800 – 1800 kg/m3, varies according to the class of blocks.

(c) Compressive Strength

Red Bricks

• Depending upon class of the red bricks, its compressive strength ranges from 3.5 to 35 N/mm2. Though IS code provides maximum strength of 35 N/mm2, the maximum strength that is available in the market is 7.5 N/mm2.

AAC Blocks

• Depending upon the density and grade of blocks, its compressive strength ranges from 2 to 7 N/mm2.

Fly ash Bricks

• Depending upon class of the fly ash bricks, its compressive strength ranges from 3.5 to 35 N/mm2. Though IS code provides maximum strength of 35 N/mm2, the maximum strength that is available in the market is 7.5 N/mm2.

Solid Concrete Blocks

• Depending upon the grade, its compressive strength ranges from 4 to 5 N/mm2.

CLC Blocks

• Depending upon the density of blocks, its compressive strength ranges from 2.5 to 25 N/mm2.

(d) Water Absorption

Red Bricks

• Water absorption of brick should not be more than 20% of its weight.

AAC Blocks

• Water Absorption of AAC block should not be 10% its weight.

Fly ash Bricks

• Water absorption of fly ash bricks should not be more than 15 – 20% of its weight.

Solid Concrete Blocks

• Water absorption of solid concrete blocks should not be more than 10% of its weight.

CLC Blocks

• Water absorption of CLC blocks should not be more than 7.5 – 12.5% of its weight.

(e) Thermal Conductivity

Red Bricks

• 0.6 – 1.0 W/m K. The amount of heat transfer from a specific material is called its thermal conductivity. The thermal conductivity of brick is high, and hence heat transfer from brick is more than that of AAC blocks.

AAC Blocks

• 0.21 – 0.42 W/m K. Thermal conductivity of AAC block is lower than red bricks and less heat transfer from block.

Fly ash Bricks

• 0.3 – 0.4 W/m K. Thermal conductivity of fly ash bricks is more than AAC block, but less than red bricks.

Solid Concrete Blocks

• 0.7 – 1.28 W/m K. Thermal conductivity of solid concrete blocks is more than red bricks.

CLC Blocks

• 0.32 – 0.54 W/ m K. Thermal conductivity of CLC blocks is less than red bricks and thus allows less.

(f) Sound Insulation/Noise Transmission

Red Bricks

• The brick wall has good sound insulation property due to its dense structure.  45 db sound is reduced by 150 mm and 50 db sound is reduced by 230 mm thick walls.

AAC Blocks

• The AAC block has good sound transmission property due to the presence of air voids. 40 – 45 db sound is reduced by 200 mm thick AAC block.

Fly ash Bricks

• The fly ash bricks have moderate sound insulation property. 37 – 39 db sound is reduced by 100 mm thick brick.

Solid Concrete Blocks

• 51 db sound is reduced by 150 mm thick wall of solid concrete blocks. Hence it has good sound insulation property.

CLC Blocks

• CLC blocks have good sound insulation properties. Depending upon density and thickness, 37 – 42 db sound is reduced by CLC block.

(g) Termite Resistance

Red Bricks

• Red bricks are not termite resistant as they are made from clay which is an organic material.

AAC Blocks

• AAC blocks are insect resistant, inorganic and solid wall construction material. AAC block do not allow spread of termites and pests and hence increase the life of wall.

Fly ash Bricks

• Fly ash bricks are insect resistant as they are made from inorganic materials. Thus they do not spread termites and pests.

Solid Concrete Blocks

• Solid concrete block does not allow the spread of termites and pests hence increase the life of wall.

CLC Blocks

• CLC bricks are insect resistant thus they do not spread termites and pests.

05. Efficiency

(a) Mortar Consumption

Red Bricks

• Requires more mortar due to irregular surfaces & more number of joints.

AAC Blocks

• Requires less mortar due to flat and even surfaces & less number of joints.

Fly ash Bricks

• Requires less mortar due to flat and even surfaces, but number of joints are same.

Solid Concrete Blocks

• Requires less mortar due to flat and even surfaces & less number of joints.

CLC Blocks

• Requires less mortar due to flat and even surfaces & less number of joints.

(b) Water Usage During Manufacturing

Red Bricks

• Requires more water for curing and hence high amount of electricity bill and labour cost.

AAC Blocks

• AAC blocks are cured by steam and block masonry also requires less curing hence less water is used and there is saving in electricity bill.

Fly ash Bricks

• Fly ash bricks are cured by steam and hence thus require less water during manufacturers. They use water like red bricks during placing on the site.

Solid Concrete Blocks

• Solid concrete blocks are cured for 7 to 14 days after casting. Hence they use a considerable amount of water during manufacturing.

CLC Blocks

• CLC blocks are cured by steam and thus masonry also requires less curing hence less water is used.

(c) Breakage & Utilisation

Red Bricks

• Average 10 to 12 % or even more breakage happens on construction site depending upon the quality of bricks. So 100% utilisation is not possible. Even at some place, due to the poor quality of bricks, wastage goes up to 33%, while loading, uploading, etc.

AAC Blocks

• Negligible breakage. Almost 100% utilization is possible.

Fly ash Bricks

• Negligible breakage. Almost 100% utilization is possible.

Solid Concrete Blocks

• Negligible breakage. Almost 100% utilization is possible.

CLC Blocks

• Negligible breakage. Almost 100% utilization is possible.

06. Environmental Impact

Red Bricks

• Red brick is not a green product. Red bricks are made from the clay which is naturally available material but it reduces the top fertile soil cover. Hence, the land available for agriculture gets reduced.
• More amount of CO2 is emitted during the manufacturing of red bricks.

AAC Blocks

• During the manufacturing process, waste of the AAC block is recycled and used again. This waste is made from the cutting process.
• Less amount of CO2 is emitted in atmosphere while manufacturing AAC blocks.

Fly ash Bricks

• Fly ash bricks utilize fly ash waste which is generated from thermal power plants. Thus it helps and solves disposal problem. Conservation of top soil is done as they do not use clay.
• Very low amount of CO2 is emitted during manufacturing process of fly ash bricks.

Solid Concrete Blocks

• Solid concrete blocks are cured for 7 days after casting, hence they use considerable amount of water during their manufacturing process.
• Less amount of CO2 is emitted in atmosphere while manufacturing solid concrete blocks.

CLC Blocks

• CLC blocks also utilize fly ash and helps in reducing solid waste for dumping. They also conserve top soil.
• Very low amount of CO2 is emitted during manufacturing of CLC blocks.

07. Cost

Red Bricks

• They are cheaper as compared to other masonry units. However, overall cost is more, as it requires more mortar both for joints and plaster. Extra bricks are to be ordered to account waste due to breakage. Cost of environmental damage is beyond calculation.

AAC Blocks

• Individual block is expensive, but the overall cost of masonry is low, as it consumes less mortar. Also for same dimensions of the walls, less number of AAC blocks are required as compared to red bricks. It also gives more carpet area or vice versa for same carpet area, it reduces built up area. It saves cost of steel also.

Fly ash Bricks

• Fly ash bricks are the cheapest masonry units. Overall cost is more as they require more mortar.

Solid Concrete Blocks

• Individual block is costlier than bricks, but the overall cost of masonry is low, as it consumes less mortar. Also for same dimensions of the walls, less numbers of solid concrete blocks are required as compared to red bricks. They are cheaper than AAC blocks and CLC blocks.

CLC Blocks

• Individual block is costlier, but the overall cost of masonry is low, as it consumes less mortar. Also for same dimensions of the walls, less numbers of CLC blocks are required as compared to red bricks. They are cheaper when compared with AAC blocks.

Special Comment

This comparison of red bricks vs AAC blocks vs fly ash bricks vs solid concrete blocks vs CLC blocks will help you in making precise selection for the walls of your home. Red Bricks are made from the natural soil. If this natural soil is used continuously for construction, time will come when natural resources will be scare. Due to this reason various alternatives such as AAC blocks, fly ash bricks, solid concrete blocks, and CLC blocks should be used for constructing a wall. From the above comparison of red bricks vs AAC blocks vs fly ash bricks vs solid concrete blocks vs CLC blocks, the user has to make a judicial and rational choice.

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