Fly ash bricks disadvantages and Advantaged | Components used

What is Fly ash bricks?

Fly ash bricks is the building material made by using class C or class F fly ash and water. The waste that comes from the combustion of coal is used for making the fly ash bricks.

Fly ash bricks have great strength and don’t require additional energy. It is eco-friendly bricks costing 20% less than ordinary bricks.

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Standard size of Fly ash bricks is 190mm * 90mm * 90mm.

Fly ash bricks disadvantages and Advantaged | Components used

In this post, I have described both, Fly ash bricks disadvantages and Advantaged. Lets read from the beginning.


Fly ash is the powder containing toxic metals like mercury, arsenic, antinomy, chromium, etc. These are metals that can create a very negative impact on the environment.

It can lower the yield in the plant and can make the soil infertile. So the proper disposition of fly ash is today’s necessity for reducing the hazard.

To overcome this effect powder containing toxic metals is converted into the bricks, which can reduce its quantity lower the environmental hazards.

According to the national science foundation in the USA, it is clarified that fly ash bricks don’t emit any mercury at all but instead it absorbs the mercury in the air and makes it good to breathe.

Components used for Manufacturing of fly ash bricks

  1. Fly ash (60%),
  2. Sand/stone dust (30%),
  3. Cement/lime (5 to 30)%,
  4. Gypsum (2 to 15)%,

Manufacturing process

  1. The quantity of the components can be changed according to the requirement and their quality. All the components are manually fade in a pan mixture and water is added as required.
  2. They mixed to have a semi-dry uniform mix. The mixture is then passed through a belt conveyor to a hydraulic machine. Here, a semi-dry mix is compacted.
  3. And these bricks are left to dry under the sun for 24 to 48 hours. Moulded bricks are air-dried for 1-2 days and water is cured for 14-21 days.
  4. Finally, the bricks are tested and packed.
Fly ash bricks disadvantages and Advantaged | Components used
Fly ash bricks

Quality check:

The quality of the fly ash bricks are checked by following test:

1. Compressive strength test

2. Water absorption test

3. Efflorescence test


  • It can also be used as a good sound and heat absorbent.
  • It Can be used in all building construction.
  • It Can be used in load-bearing and nonload bearing external and internal walls.
  • It is used to construct go-downs and warehouses.

Fly ash bricks advantages

  • It has very low weight so is portable.
  • It reduces the dead load on the structure.
  • It has a very high fire resistance capacity.
  • Have a very smooth surface so require less mortar in brickwork.
  • It is machine-made so, it becomes a high-quality brick.
  • It has high durability.
  • Lower manpower is required.

Fly ash bricks disadvantages

  • It has low mechanical bonding strength.
  • The large size will have more breakages. so, one cannot use large size bricks.
  • Is preferable only in a warm area.
  • Cold season is not economical for these bricks.
  • It has lower compressive strength so It can’t be used for the heavy structure.
  • Materials are not easily available.

I hope this article remains helpful for you.

Happy Learning – Civil Concept

Contributed by,

Shreya Parajuli

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"Structural Engineer" with over 5 years of experience in estimation, structural design, and surveying. I am passionate about using his skills to create safe and sustainable structures. I am also a keen writer, and I enjoy sharing my knowledge and experiences with others.

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