AAC Fundamentals

What Is Autoclaved Aerated Concrete (AAC)?

Autoclaved Aerated Concrete (AAC) is a lightweight, precast building material used for walls, blocks, panels, and building systems. It combines structural capability with thermal insulation, fire resistance, and acoustic performance in a single material.

How AAC Is Made

AAC is produced from a mix of cement, lime, fine silica (sand or fly ash), water, and a small quantity of aluminium powder. The aluminium reacts with the alkaline mix to release hydrogen, which forms millions of tiny air cells throughout the material. After an initial set, the material is cut to size and cured under heat and pressure inside an autoclave. The result is a stable, dimensionally accurate material that is much lighter than conventional concrete.

Key Properties of AAC

  • Lightweight: The aerated structure makes AAC significantly lighter than dense concrete, reducing structural loads and easing handling.
  • Thermal insulation: The trapped air cells give AAC good insulating properties, supporting energy efficiency.
  • Fire resistance: AAC is non-combustible and performs well in fire-rated assemblies.
  • Acoustic performance: Its cellular structure helps reduce sound transmission.
  • Workability: AAC can be cut, drilled, and shaped with standard tools.

Common AAC Product Forms

AAC is manufactured in several forms to suit different applications, including:

  • Standard and cored blocks for wall construction
  • U-blocks for beams and lintels
  • Reinforced floor and roof panels
  • Wall and cladding panels
  • Lintels and other reinforced elements

Where AAC Is Used

Because it combines several performance benefits in one material, AAC is used across many sectors — from residential and commercial buildings to industrial facilities, hospitality, educational projects, and infrastructure. Explore real-world examples in our project references, or learn more about AAC product systems.

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Frequently Asked Questions

What is AAC made of?

AAC is typically made from cement, lime, sand or fly ash, water, and a small amount of aluminium powder, which reacts to create air bubbles. The material is then cured under heat and pressure in an autoclave.

Is AAC strong enough for buildings?

Yes. AAC is a structural and non-structural building material used for load-bearing and infill walls, panels, and floor and roof elements, depending on the product and engineering design.

Is AAC fire resistant?

AAC is non-combustible and provides fire resistance, which is one reason it is widely specified for fire-rated wall assemblies.

Where is AAC used?

AAC is used in residential, commercial, industrial, hospitality, educational, and infrastructure projects for walls, partitions, panels, and other building systems.