Fly ash is a waste product of a power generating plant and that is reused in concrete by partial replacement of cement. It is also used for making bricks is called Fly Ash Brick. Fly Ash Bricks are used as the alternative material for burnt clay bricks for masonry works. The raw material used in the fly ash brick such as fly ash, sand/stone, and ordinary Portland cement. The test conducted to test fly ash brick includes compressive strength test, Water Absorption Test, Efflorescence Test.
What Is Fly Ash Brick?
Fly ash brick is a building material, especially masonry units that are utilized in the construction of buildings. They are supposed to be a part of good and affordable building materials.
The containing class C or class F fly ash and water. Fly ash brick is generally compressed at 28 MPa and cured for 24 hours in a 66°C steam bath, then stiffened with an air-entrainment agent, the bricks can last for more than 100 freeze-thaw cycles.
Owing to the huge concentration of calcium oxide in class C fly ash, the brick is interpreted as “self-cementing”. The manufacturing method of fly ash bricks saves energy, decreases mercury pollution in the environment, and often costs 20% less than conventional clay brick manufacturing. Fly ash brick considered good and inexpensive building materials including class C, fly ash, and water.
Fly ash brick is environmentally friendly and manufactured by hydraulic pressure machines. They are 28% lighter than ordinary clay bricks and have a compressive strength greater than 40Mpa than ordinary bricks. They are economical and eliminate the need for plaster, it can decrease high construction costs and soil erosion.
Read More: 30+ Types of Bricks used in Construction
Properties Of Fly Ash Bricks:
Appearance: The bricks have a satisfactory cement color, which is uniform in shade and smooth, but does not need plastering for building works
Thermal Conductivity: They do not absorb heat and give extreme light reflection.
Sound Insulation: It gives an adequate degree of sound insulation.
Fire And Vermin Resistance: They have adequate fire resistance, it has no difficulty with vermin attacks.
Durability And Moisture Content: These blocks are highly durable, the absorption of moisture is 6–12%, which decreases the humidity of the walls.
Toxicity And Stability: When mixed with lime, fly ash turns into a non-toxic commodity thus has potential as a good building material.
Fly Ash Brick Size:-
IS Code for fly ash bricks is IS 13757 (1993): Burnt clay fly ash building bricks-Specification
For Modular Size,
Length is 190± 4mm
Width is 90±2 mm
Height is 90±2 mm and 40±2 mm
For Non-Modular Size
Length is 230± 4mm
Width is 110±2 mm
Height is 70±2 mm and 30±2 mm
Fly Ash Bricks Manufacturing Process:
Manufacturing of Fly ash bricks (of size: 230 x 108 x 75 mm) is done by using a manually operated machine. The following points were followed in the manufacturing of compacted fly ash bricks
(1) Fly ash and sand (fly ash bricks mixing ratio is 0.35 fly ash and 0.65 sand, by weight) were mixed in a dry state. Required quantities of lime and gypsum were added to the dry mixture. Both these procedures were carried out in a mechanical mixer (for 5 minutes) extremely that a uniform mixture of fly, ash-sand-stabilizer was collected.
(2). A Uniformed combination of fly ash-sand-stabilizer was spread into a thin layer (100 mm thickness). The required quantity of water (10% for FAL10 and FALG10 bricks, and 12% for FAL17 and FALG17 bricks) was sprinkled and mixed manually with the relief of a spade in order to assure that moisture is uniformly allocated in the mixture.
(3) Known amount of the raw mixture was weighed and poured into the machine mould. indicates the filled mould prepared for compaction. After closing the lid the compaction is accomplished through the movement of a piston connected to the toggle lever
(4) After the compaction stroke the lid is opened and the brick is ejected out and protected in a stack for curing. The stack of fly ash bricks was coated with wet gunny cloth and water is sprinkled three to four times every day such that the whole stack is moist. The bricks were cured for 28 days and then were enabled to dry in the open atmosphere for four weeks and then utilized for testing.
Watch Video of fly ash bricks manufacturing process with automatic machine.
Fly Ash Bricks Machine Price List:
Fly ash bricks manufacturing machines also available in markets which enables large quantity production in a short period of time. Fly ash brick machine are of two types 1) Automatic 2) Manual Operation Machine.
Following are fly ash bricks machine price or fly ash bricks making machine cost is given below,
|Operation Types||Minimum Price||Maximum Price|
|Automatic||Rs 1550000/Unit||Rs 2500000/Unit|
|Automatic||Rs 610000/Unit||Rs 1975000/Unit|
|Manual||Rs 150000/Unit||Rs 750000/Unit|
|Semi-Automatic||Rs 270000/Unit||Rs 1600000/Unit|
Read More: 7 Brick Test to Decide Quality of Bricks
Fly Ash Bricks Advantages:
The Appearance of the fly ash brick is impressive due to their satisfying color like cement, uniform size, and smooth finish. Due to uniform size, mortar mandatory for walls and plastering reduced nearly by 40- 50%.
of Paris (Gypsum plaster), putty can be applied rapidly without a baking coat of plaster. These bricks are independent of the cracks, wrap age, organic matter, pebbles, and nodules of the free lime.
The compressive strength of the fly ash brick is relatively high (9-10 N/mm2). Due to high strength no breakages/wastages during conveyance and handling. The less thickness of joints and plaster reduces cracking in plaster. These bricks do not result in any extra load for the design of structures and give better earthquake resistance. It enhances strength over time and offers incredible strength to the building.
3. Thermal Properties:
The thermal conductivity of fly ash bricks is nearly 0.90 – 1.05 W/m2. They absorb less heat. The pozzolanic effect between the fly ash and lime generates less heat. It protects your building cooler in summer, therefore most suitable for Indian climates.
These bricks are highly durable and less permeable. The lower permeability can efficiently lessen the effect of efflorescence on bricks. The fly ash bricks are lessened porous, consume less water, and decrease dampness on the walls. It is also highly resistant to the attack by mild acid, water, and sulfate.
4. Sound Insulation:
The Construction with the fly ash bricks provides decent sound insulation to the building.
5. Fire Resistance:
The fly ash bricks are highly fire-resistant compared to the normal clay bricks.
The Fly ash bricks are environmentally friendly as they are prepared of waste materials that reach from the combustion of coal in power plants. There is no pollution or environmental damage, deemed as a white category product.
The fly ash bricks have easy workability and consume less water. Unlike clay bricks, they do not impose draining in water for 24 hours. The sprinkling of water before use is sufficient. The construction procedure is similar to clay brick construction and does not need any extra training for the masons.
These bricks are commonly available closer to thermal power plants. However, finding dealers in all main cities and towns wouldn’t be a difficulty.
The similar number of fly ash bricks will enclose more areas than clay bricks. Consumption of the mortar is also low. It’s Requires less labor. The cost is almost 30% lower than clay bricks.
Due to their lightweight, these bricks are desirable for multi-story structures. Less weight indicates less stress on the building. These bricks can be utilized in load-bearing external walls in low/mid structures, non-load-bearing inner walls in low/mid structures, and non-load-bearing inter outer walls in high-rise buildings.
Fly Ash Bricks Disadvantages:
- Not all fly ash is convenient for construction, those are manufactured in power plants usually similar to concrete, while others may desire beneficiation. It is relatively important to use only high-quality fly ash to avoid negative impacts on the structure.
- If bricks are not prepared properly, it has no strength and not suitable for construction. Poor quality bricks have an adverse impact on concrete. It can increase permeability, occurring in damages to the structure.
- Bonding with the concrete is lower due to the brick smooth surface.
- Restriction in size. Only modular size bricks can be manufactured. The bigger size brick will have more breakages.
- Fly ash bricks only applicable for subtropical areas, or where the atmosphere is warm because fly ash bricks do not consume heat. But in the winter season, it is not effective.
Raw Materials Used In Fly Ash Bricks:-
1. Fly ash 60%
2. Sand / Stone dust 30%
3. Ordinary Portland cement/(Lime + Gypsum) 10%
The total formula of material 100%
The strength of fly ash brick produced with the above configurations ranges between 7.5 MPa and 10 MPa. The Fly ash bricks are tougher and lighter than clay bricks.
The fly ash bricks have main ingredients such as fly ash, water, quicklime or lime sludge, cement, aluminum powder, and gypsum. Auto craving raises the hardness of the block by stimulating quick curing of the cement. Gypsum conducts as a long-term strength gainer.
Utilizing the fly ash bricks in the buildings decreases the dead load, permitting one to save around 30 to 35% of structural steel, and concrete.
Commercial processes fall into two sectors; the lime route, and the cement (Ordinary Portland Cement) path where the latter is utilized as a source of lime.
In the lime path, the configuration is fly ash (50%), slaked lime (30%), and anhydrous gypsum (20%), to which 3 to 4 times of stone dust, sand, or any inert filling material can be added. In the cement route, the composition is fly ash (76%), Ordinary Portland cement (20%), and anhydrite (4%), to which 3 to 4 times of filling material can be added.
Uses Of Fly Ash Bricks:
- Fly ash bricks are generally used in low and medium-sized structures, load-bearing exterior walls.
- On load-bearing structure internal walls.
- Fly ash bricks can be used in the building industry.
- Brick is used in high load-bearing exterior or interior walls in high-rise buildings.
- Fly ash bricks are used as an alternative material for burnt clay bricks which is one of the most important building materials obtained for the construction of housing and buildings. The fly ash building bricks are inefficient in all types of brick masonry works and can replace the conventional burnt clay bricks in almost all applications.
- Fly ash bricks used in multistory structures, factories, house construction, high-rise buildings, power plants, warehouses.
Fly Ash Bricks Price:
Fly ash bricks price is comparatively lower than red bricks price. Fly ash Bricks price list is given as per size of bricks,
Fly ash Bricks 230x110x75mm
M5+ Grade Fly Ash Bricks Price ₹4.40/-
M7.5+ Grade Fly Ash Bricks Price ₹4.90/-
M10+ Grade Fly Ash Bricks Price ₹5.40/-
Difference Between Fly Ash Bricks vs Red Bricks:
Following are key comparison point for Fly ash bricks vs red bricks,
Red Clay Bricks
Fly Ash Brick
|1||Not in a similar colour as the colour of brick depends on the category of soil and quality control during production.||The colour of fly ash brick is similar to the brick manufacturing is conducted using machinery in controlled conditions.|
|2||Clay bricks are unequal in shape as mostly clay bricks are made manually.||Uniform in shape and smooth in the finish as the manufacturing is accomplished using machinery.|
|3||As the surface finish is not flat or straight, plastering is necessary.||As the surface is flat and joints are thinner, no plastering is needed in normal cases.|
|4||Clay brick is Heavier in weight.||Fly ash brick is lighter as the major configuration is fly ash.|
|5||Clay bricks are more porous compare to fly ash brick.||Fly ash brick are minor porous|
|6||The cost of clay brick is greater than fly ash brick.||The expense of these bricks is almost 30%lower than clay brick.|
|7||Proceeding with the use of clay bricks in the construction industry will lead to a large loss of fertile topsoil. This could be a||This is composed by using by-products of Thermal Power Plant. Which preserves the environment from occurring pollution.|
Image Courtesy: Image3
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