FLY ASH BRICKS

FLY ASH BRICK MATERIALS ARE CONTAINING CLASS C FLY ASH AND WATER. OWING TO HIGH CONCENTERATION OF CALCIUM OXIDE IN CLASS FLY ASH THE BRICK IS CONSIDERED AS “SELF-CEMENTING”

TYPES OF FLYASH BRICKS

• CLAY FLYASH-Manufacturing process of clay flyash bricks by manual or extrusion process involves mixing of flyash (60 %) with clay of moderate plasticity •Flyash – Sand Lime Bricks.

In presence of moisture, fly ash reacts with lime at ordinary temperature and forms a compound possessing cementitious properties

•Cold Bonded Lightweight Flyash Bricks, Blocks and Tiles

The material can be produced in a variety of building blocks, bricks and tiles, depending on local markets and regulations•Flux Bonded Flyash Bricks Blocks and TilesThe process is similar to the one in the conventional tile industry: fly ash is mixed with less than 10 % plastic clay and a few additives and tiles, bricks or blocks are pressed

BRICKS PROPERTY OF FLYASH Appearance

These bricks have a pleasing colour like cement, are uniform in shape and smooth in finish, also, they require no plastering for building work. The bricks are of dense composition, uniformly shaped with/without a frog, free from visible cracks, warp-age, organic matter, pebbles and nodules of free lime. They are lighter in weight than ordinary clay bricks and less porous too.

Sound insulation

It provides an acceptable degree of sound insulation Flyash bricks have a good fire rating. It has no problems of vermin attacks or infestation.

 

•Durability and moisture resistance

These blocks are highly durable, after proper pointing of

joints, the bricks can be directly painted in dry distemper and

cement paints, without the backing coating of plaster.

Rectangular faced with sharp corners, solid, compact and

uniformly Water absorption is 6-12% as against 20-25% for

handmade clay bricks, reducing dampness of the walls

Thermal conductivity is 0.90-1.05 W/m2 ºC (20-30% less than those of concrete blocks). These bricks do not absorb heat; they reflect heat and gives maximum light reflection without glare.

•THERMAL CONDUCTIVITY

Structural Capability These bricks can provide advantages being available in several load-bearing grades, savings in mortar plastering, and giving smart looking brickwork. High compressive strength eliminates breakages/wastages during transport and handling, the cracking of plaster is reduced due to lower thickness of joints and plaster and basic material of the bricks, which is more compatible with cement mortar

Buildability and availability The blocks have an easy workability and high compressive strength eliminates breakages/wastage during handling giving a neat finish, with lower thickness of joints and plaster

•QUALITY OF BRICKS DEPENDS ON THE

FOLLOWING FACTORS 1. Quality of raw materials

 

2. Proportioning of raw materials

 

3. Handling and mixing of raw materials

 

4. Handling & pressing of the mix

 

5. Curing period

QUALITY OF RAW MATERIALS

For production of good quality Fly Ash Bricks (FAB), fly ash should conform to its chemical and physical requirements •Sand/Stone dust

h

•FLY Ash

Deleterious materials such as clay and silt in sand/stone dust shall not be more than 5%•LimeI ) The sludge lime contains extraneous materials.II) It is generally wet.III) It contains lumps.IV) It is difficult to know the % of available lime (as CaO).

• Gypsum Chemical or mineral gypsum can be used for making Fly Ash Brick. The gypsum should be free of lumps and having purity to about 60%.

•CementOrdinary Portland cement of 43/53 grade can be used in place of lime and gypsum. Since it is a factory finished product and thus generally does not require any testing.

•Raw Material Proportion1. For fly ash, sand, sludge lime and gypsum bricks

Sand/Stone dust 20-25% Sludge lime 15-20% Gypsum 5%

Fly ash 55-60%

2. For fly ash, sand, hydrated lime and gypsum bricks.

Fly ash

60-65%

Sand/Stone dust

18-27%8-12% Hydrated lime

Gypsum

5%

3. For fly ash, sand and cement bricks

Fly ash 50-60%

Sand/Stone dust 32-40%

8-10%Cement

•Fly ash bricks have many advantages like

Light weight

Economical

Environmental friendly

Saving of fertile land, pure water

More compressive strength

Use of wastage

FUTER SCOPE

Fly ash for construction of roads and embankments.

Feasibility study of the large scale Fly ash brick manufacturing units.

Fly ash in Aerated Autoclave Concrete

CONSIDERING the fly ash - lime – gypsum- sand combination idea-can be extended to manufacture cement from it.

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