Autoclaved Aerated Concrete block (also called Autoclaved Cellular Concrete) is an economical, sustainable, lightweight solid block that provides thermal and acoustic insulation and is also fire and termite resistant.

Manufacturing Process

To manufacture AAC, portland cement is mixed with lime, silica sand, or processed fly ash, water, and aluminium powder or paste and poured into a mould. the reaction between aluminium and concrete causes microscopic hydrogen bubbles to form, expanding the concrete to about five times its original volume. after evaporation of the hydrogen, the now highly closed cell, aerated concrete is cut to size and formed by steam curing in a pressurized chamber (an autoclave).
The result is a non-organic, non-toxic, airtight material that can be used for all walling applications. aac generates no pollutants or hazardous waste during the manufacturing process.
AAC is well suited for urban areas with high rise buildings and those with high temperature variations. Due to lower density, high rise buildings constructed using AAC require less steel and concrete for structural members. Requirement of mortar for laying AAC blocks is reduced due to less number of joints. Similarly material required for rendering is also lower due to dimensional accuracy of AAC. Better thermal efficiency of AAC makes it suitable for use in areas with extreme temperature as it eliminates need for separate materials for construction and insulation leading to faster construction and savings.


Sl.No. Parameter AAC Block Conventional Red Brick
1 Size ( L x H x B) 60cm x 20cm x 10 - 30 cm 23cm x 7.5cm x 11.5cm
2 Precision in Size Variation 1.5 mm (+/-) Variation 5mm (+/-)
3 Compressive Strength 35-40 Kg/cm2 25-30 Kg/cm2
4 Dry Density 550-650 kg/m3 1950 Kg/m3
5 Wet Density App. 800 Kg./m3 App. 2400 Kg./m3
6 Fire Resistance 2 to 6 Hour depending on thickness 2 Hours
7 Sound Reduction Index1 (Db) 45 for 200 mm thick wall 50 for 230 mm thick wall
8 Thermal Conductivity 0.16 (Kw-m/C) 0.81 (Kw-m/C)
9 Consumption per M3 with 1:6 0.5 bag of Cement 1.35 bag of Cement
10 Construction Time per mason 30 Sqm. More can be constructed if total system is used 20 Sqm. with Conventional Brick