What is AAC Block?
Autoclaved aerated concrete (AAC), also known as autoclaved cellular concrete (ACC), autoclaved lightweight concrete (ALC), autoclaved concrete, porous concrete, Ytong, Hebel Block, Aircrete, thermalite.
When AAC was first developed?
AAC was developed in 1924 by a Swedish architect who was looking for alternative building material with wood-like properties good thermal insulation, solid structure and easy to work with but without the inconvenience of combustibility, decay and termites. It has been refined into a highly thermally insulating concrete material for indoor and outdoor construction. AAC products contain blocks, wall panels, floor and ceiling panels and lintels.
Advantages of AAC Blocks
AAC block offers several significant advantages over other cement construction materials, one of the most important being its lower environmental impact.
- Improved thermal efficiency reduces the heating and cooling load in buildings.
- The Workability allows accurate cutting, which minimizes the generation of solid waste during use.
- It has a lower environmental impact in all phases of its life cycle, from the processing of raw materials to the disposal of waste.
- It’s Lightweight saves cost and energy in transportation.
- Its Lightweight saves labour expenses.
- Lightweight increases chances of survival during seismic activity.
- Larger size leads to faster masonry work.
- Termite/Pest Resistant, Cost-Effective, Precision,
- Earthquake Resistant.
- Easy Workability and Design Flexibility.
- Thermally Insulated & Energy Efficient, Fire Resistant, Eco-friendly.
ACC Blocks size
|S.No.||Particulars||Size (L x B x H) in mm|
Applications of AAC Blocks
- Hotels, Motels & Restaurants
- Industrial & Cold Storages
- Hospitals & Medical Clinics
- Retail & Warehouses
- Office & Religious Buildings
- Power Plant & Fire Walls
- Public Facilities
- Single & Multi-Family Homes
- Shaft walls
- Education Institutes Construction
- Auditorium & Theaters
- Multi-storey Buildings
Technical Comparison of Blocks
|Parameter||AAC Block||Concrete Block||Brick|
|Size||(600x200x100-300) mm||(400x200x100-200) mm||(230x115x75) mm|
|Compressive Strength||30 – 50/Kg/3Cm2||40 – 50/Kg/Cm2||25 – 30/Kg/Cm2|
|4-6/Hour Depending On Thickness|
|Sound Reduction Index(DB)||60 For 200 mm thick wall||_||40 For 230 mm Thick Wall|
|Thermal Conductivity w/(Km)||0.25|
Physical Properties of Autoclaved Cellular Concrete Blocks Clauses (4.1,8.3,8.4,8.5,11.2,11.3 and 11.4) IS :2185(Part-3) 1984
|S.No.||Density in oven-dry condition||Compressive strength min grade 1 N/mm2||Compressive strength min grade 2 N/mm2||Thermal conductivity in air-dry condition w/MK|
|1||451 to 550||2||1.5||0.21|
|2||551 to 650||4||3||0.24|
|3||651 to 750||5||4||0.30|
|4||751 to 850||6||5||0.37|
|5||851 to 1000||7||6||0.42|
ACC Block Plant
|1||Material hopper||10||Cutting machine|
|2||Slurry making tank||11||Tilting crane|
|3||Slurry making pit tank||12||Windless machine|
|4||Silo||13||Steam trolley car|
|5||Pouring section platform||14||Autoclave|
|6||Pouring mixer||15||Ferry car outlet|
|7||Ferry cart||16||Side plate return roller system|
|8||Mould box||17||Finish block dispatch point|
Raw Material Required
Fly Ash /65-70%
Fly-ash material is freely available in Thermal power plant. A lot has been said about this raw material in Different forums & Environmentalists. There are no taxes levied on this item.
Lime / 8-12%
Different qualities of lime are available and depending on the raw materials. The mix design can be chosen to get the optimal quality of production. Quick lime is a requirement for giving the real aeration to the product.
OPC Cement / 10-15%
The project aims to utilize OPC cement as the main binder material. it will give faster strength to the blocks besides giving improved consistent quality. it also ensures better cost-effectiveness for the same. Using OPC cement will be a standardized practice.
Gypsum / 4.5-5%
This too is an industrial waste. This is available as an industrial by-product of Fertilizer plant.gypsum is responsible to give long term strength to block.
Aluminum Powder / 0.5%
Finely ground aluminium powder is used in very limited quantity (less than 0.5%) so that it reacts with active lime, and silica in base material to make the aeration, and swell the product, making it very light in weight. The density of the product reduces to 600-650 kg/cum.
Procedure OF Production
1. Firstly, batch the measured raw material.
2. Feed raw material into pouring mixer for slurry making.
3. pour the mixer slurry into the mould.
4. After pre-curing under a certain temperature and time, the block would reach certain hardness &
5. Tilting crane separate the already- formed material from the mould and transfer it with side plate to the cutting cart.
6. Cutting machine horizontally & vertically cut the foamed material.
7. Group of steam Trolley with cake move into Autoclaves.
8. In Autoclaves sustained pressure & temperature is maintained for curing cake.
9. crane transfer the finished product to the dispatch point.
10. Move the finished blocks out of Autoclaves.
11. Packed for loading.
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