What is Autoclaved Aerated Concrete (AAC) Block?

Autoclaved aerated concrete (AAC) Block is a lightweight, precast building product used around the world as a superior substitute for traditional clay bricks and is available in blocks and panels of various sizes. AAC Block is an ideal material for structural walls, firewalls, sound walls, and floor and roof systems.

Is AAC Block load-bearing?

AAC Blocks and panels with a minimum of 8" thickness are suitable for load-bearing applications, when used in accordance with our published design aids and allowable stress listings. 6'' blocks may be used for some interior loadbearing applications. Loadbearing applications require vertical cores reinforced with rebar and concrete. Code requires cores at corners, doors and windows. For design information, please consult our Technical Manual, or contact us to request a technical manual.

What type of mortar is used with AAC Block?

Traditional sand cement mortar made at site can be used but it is advisable to use Thin-bed mortar designed especially for AAC Blocks. It is delivered in ready-to-mix powder form. It is polymer modified Portland cement specifically designed to retain water from entering the pores of AAC blocks, which perfectly bond AAC blocks. Just 2-3 mm thin mortar bed is needed to adhere the blocks. This is extremely thin joint which also prevents heat loss and speeds installation.

What type of finishes is available?What type of finishes is available?

Many of the conventional exterior finishing system such as one coat plastering and two coat systems can be used over AAC Blocks as an exterior finish. Other options such as stucco, acrylic finishes, brick, stone, siding, or approved paints can also be used. On the inside of the building, AAC Block may be directly finished with Gypsum boards sheetrock, plaster, stucco, wood panel or tiles.

Is AAC Block safe and time tested?

Yes, AAC Blocks are extremely safe and time tested , they are being used in construction since 1923 in Europe and in India they are being used since 1972 , moreover AAC Blocks are probably the safest building product available . Tests conducted by independent laboratories shows that AAC is not hazardous or toxic. It doesn't emit fumes or emit radiation above that of familiar food. There is no waste produced during manufacturing as well it neither contains nor emits toxic substances.

Why is AAC a new product in India?

AAC manufacturing plants are more expensive to build than brick kilns. Over the years, with increasing labour & fuel costs the price of bricks has been steadily increasing. Total installed cost of brick walls has recently surpassed the threshold price of block walls, making AAC more attractive now than it has been in the past.

How do you hang heavy items like cabinets or shelves on AAC walls?

Fasteners are available that easily drive into AAC walls and are capable of securing heavy items. These fasteners are similar to standard concrete "spread-fast" anchors. Since AAC is less dense than standard concrete, fasteners can be driven in with a hammer. Specialty drills are not required. Unlike stud walls, fasteners can be placed anywhere in AAC walls. No need to explore to find studs for hanging heavy objects.

AAC Block has lesser water absorption compared to bricks even though AAC Block is porous. How is it possible?

AAC has a honeycomb structure and the pores in AAC are discontinuous. This prevents any capillary action taking place in blocks and hence does not allow water to pass through it.

How AAC Block wall masonry is cost effective in comparison to brick wall masonry?

AAC Blocks are 9 times the size of traditional bricks. These results in substantial saving in cement due to fewer joints compared to brickwork and finished plasterwork, more over AAC blocks are factory finished with precise edges and shapes. This results in consumption of substantially less plaster, POP, or Putty finish, which reduces walling cost in AAC blocks.

Due to lightweight and low density, over all dead load reduces, thus there is saving structural steel consumption compared to conventional clay masonry. There is increase in carpet area as well by 3% to 5% as well depending on design.

As the blocks are lighter in weight and size is also bigger the construction speed is higher and there is also saving in operating cost which is realized through reduction in maintenance, energy bills and insurance.

How is concealed wiring installed in AAC walls?

Easily, there are standard methods for installing wiring in autoclaved aerated concrete (AAC) walls. The walls are built first. The electrician draws directly on the block to indicate where the wires will go. The AAC installer uses a manual or electric router to cut channels on the inside of the walls. After the electrician installs the wiring, the wall is plastered or filled with regular plaster, which allows a clean crack free smooth finish to wall. Requires no pre-planning, and changes are easily made. Conduits are usually required. Extra switches and receptacles can still be added by the routing method.

Why is AAC Block considered as a Green Building product?

Raw Materials consist of Recycled Post-Industrial Waste
Up to 70% of the raw materials in AAC blocks is fly ash which is a national waste. Reclaimed gypsum is also used in the process.

Non-polluting Manufacturing
Autoclaved Aerated Concrete manufacturers use a closed-loop manufacturing process, so that nothing is ever released other than clean steam. Product trimmings, slurry and water are reprocessed, and steam is reused whenever possible.

Resource Efficiency
The end product is approximately 80% entrained air and 20% mass. Thus 5 parts AAC are produced from just 1 part raw materials.

Low Energy Consumption throughout Lifecycle
The total energy consumption to produce AAC is 1/3rd that of comparable building materials. When installed, AAC results in tremendous energy savings for heating and cooling the building. In fact, the fly ash used in AAC saves more energy in that state, than it produced when the coal was burned.