AAC / ALC Blocks

AAC/ ALC Blocks
  • Acoustic construction
  • Precast exterior walls
  • Roof insulation and waterproofing
  • Green construction
  • Additional floors to existing construction
  • Building material for high rises
  • Air- conditioned buildings
  • Low cost housing
Fly Ash


This Raw material is freely available in Thermal Power plants. Transportation charges are only to be attended by the entrepreneur.



This Project aims to utilize OPC cement as main binder material. It will give faster strength to the bricks, besides giving improved consistent quality. It also ensures a better cost effectiveness for the same. Using OPC will be a standardized practice. The other prime advantages of using OPC (compared to other binders) is it?s easy availability locally through nationwide Retail Network of Cement Companies.



Active powered lime is a requirement for giving the real aeration to the product. In phase 1 we can aim to buy the active lime directly. 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.

Aluminium Powder

Aluminium Powder

Finely ground Aluminium power 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 weight product.



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 the Blocks.

Mixing Section:

Mixing Section

  • The first stage of mixing process is making Fly Ash Slurry. According to the design, Water and Fly Ash discharged in the Slurry Mixer with the help of Conveyor Belt. After that this slurry, gets discharged in to the Slurry Tank. This is the second stage of refining process. Now with the help of pump this mixture pumped to mixer.
  • Through this Screw Conveyor, Cement and other ingredients are poured in to the mixer. These ingredients are weighed by control panel.
  • In the end according to the duty cycle of mixer, the slurry is discharged in to Mould.

Cutting Section

Cutting Section

  • After the Mould gets filled up to a certain level, after that, transferred to the Storage Area with the help of Driving Device Machine. It takes around two to three hours for the Slurry to become a Concrete Cake.
  • Now the Mould is removed with the help of Crane and only Cake is transferred to the Wire Cutting Machine.
  • Here the cutting process takes place with the help of this Wire Cutting Machine. The Cake is now ready for further process

Boiler Section : (ALC Block Procedure)

Boiler Section

  • These Cake pieces are now ready to sent in to the steaming chember, through Driving Device Machines. After filling up one chamber, both the doors get closed by operator.
  • The operator now starts the Boiler machine. This Boiler machine runs with the help of wood, as this is a cost effective measure. The Cakes are kept inside for around 10 to 12 hours
  • In the end, Cake Trolley is discharged out of the Steaming Chember and is kept in stocking area for around 4 days. Now these Blocks are completely ready for Commercial use.

Boiler Section : (AAC Block Procedure)

AAC Boiler Section

  • These Cake pieces are now ready to sent in to the Autoclave.
  • Cake inside autoclave kept around temperature under high pressure for 10 hrs
  • After that, cake removed from the autoclave and blocks are ready for commercial use.

Technical Comparison

AAC Blocks
Conventional Red Bricks


30-40 kg/ cm2

30 -80 kg/ cm2


Shape & Size

Uniform & Regular

Non Uniform & Irregular


Plaster Thickness

10 ? 12 mm

15 ? 20 mm



600- 750kg/ cm3

1500 ? 1900 Kg/ cm3


Mortar Consumption




Mortar Joint Thickness

8 ? 10 mm

15 ? 18 mm


Breakage/ Wastage

Nil ? 0.5%

8? - 10%


Comparison Between AAC Block & Bricks

AAC Block
Clay Brick


600 x 200 x 100-300mm

230 x 115 x 75mm


Variation in dimensions




Compressive Strength

30 -40 kg/cm2

25 -30 kg/cm2


Dry Density

550-700 kg/m3

1950 kg/m3


Wet Density

?800 ? 850kg /m3 (Approx)

2400 kg / m3


Fire Resistance

4-6 hour depending on thickness

2 hours


Sound Reduction Index (dB)

45 for 200mm thick wall

50 for 230mm thick wall


Energy Saving

32 % (App.) Air-Condition Load  Both  Both Heating And Cooling Will Come Down

No Saving


Thermal Conductivity

0.16 ? 0.17 (approx)

0.81 approx


Mortar Consumption

0.018 Per M3 With 1:6 / 0.5 Bag Of Cement

0.1 Per M3 With 1:6 / 1.35 Bag Of Cement