Description/ Specification of AAC Blocks (Autoclaved Aerated Concrete)
Overview of AAC Blocks
Autoclaved Aerated Concrete (AAC) blocks are a precast, foam concrete building material that is lightweight and has become popular in contemporary construction for its high thermal insulation, fire resistance, and environmental friendliness. First developed in the early 20th century, AAC blocks are today universally applied in residential and commercial construction worldwide because of their many advantages over traditional clay bricks or concrete blocks.
Properties of AAC Blocks
AAC blocks consist of a mixture of cement, lime, sand (or fly ash), water, and a slight proportion of aluminum powder. The aluminum reacts with the lime and produces hydrogen gas, which forms minute air bubbles in the mixture. This provides AAC with its light and porous nature. Some notable properties are:
Notational density: Approximately one-third of the weight of conventional bricks, hence lower dead load on the structure.
Thermal Insulation: Air pockets achieve good resistance against heat, minimizing heating and cooling expenses.
Sound Insulation: Dampenability of sound by the porous nature makes it suitable for city locations.
Fire Resistance: High temperature resistance by AAC blocks providing protection against fire of up to 6 hours based on thickness.
Durability: Pest, mould, and water leakage resistance makes the structure long-lasting.
Precision: Uniform size and finish are ensured due to the factory-made blocks.
Manufacturing Process
The manufacturing of AAC blocks involves the following major steps:
Raw Material Preparation: Fly ash (or sand), lime, cement, water, and aluminium powder are measured out and mixed in a specific proportion.
Mixing and Pouring: Ingredients are mixed to form a slurry and poured into huge moulds. Aluminium reacts with lime, evolving hydrogen gas and forming a cellular structure.
Pre-curing: The mixture hardens and swells in moulds for a few hours, rising as dough does.
Cutting: When the mixture hardens a little, it is removed from the moulds and cut into blocks of required sizes with steel wires.
Autoclaving: The cut blocks are subsequently cured in a high-pressure steam chamber (autoclave) at approximately 180–200°C and 12 bar pressure for 8–12 hours. This treatment makes the blocks stronger by transforming calcium hydroxide and silicates into tobermorite crystals.
Drying and Packing: Cured blocks are then dried and packaged for transport.
Features and Purpose
AAC blocks are intended to perform structural as well as non-structural functions. Their main features are:
Eco-Friendly: Utilizes industrial waste (such as fly ash), lowers emissions because of reduced transportation load, and reduces site wastage.
Faster Construction: Big size and lower weight facilitate faster construction of the wall and simpler handling.
Energy Efficiency: Superior insulating capabilities lower the energy consumption of buildings.
Reduced Mortar Usage: Thin joint adhesives eliminate thick mortar beds, reducing cement and sand needs. #AACblocks
AAC Blocks (Autoclaved Aerated Concrete)
Overview of AAC Blocks
Autoclaved Aerated Concrete (AAC) blocks are a precast, foam concrete building material that is lightweight and has become popular in contemporary construction for its high thermal insulation, fire resistance, and environmental friendliness. First developed in the early 20th century, AAC blocks are today universally applied in residential and commercial construction worldwide because of their many advantages over traditional clay bricks or concrete blocks.
Properties of AAC Blocks
AAC blocks consist of a mixture of cement, lime, sand (or fly ash), water, and a slight proportion of aluminum powder. The aluminum reacts with the lime and produces hydrogen gas, which forms minute air bubbles in the mixture. This provides AAC with its light and porous nature. Some notable properties are:
Notational density: Approximately one-third of the weight of conventional bricks, hence lower dead load on the structure.
Thermal Insulation: Air pockets achieve good resistance against heat, minimizing heating and cooling expenses.
Sound Insulation: Dampenability of sound by the porous nature makes it suitable for city locations.
Fire Resistance: High temperature resistance by AAC blocks providing protection against fire of up to 6 hours based on thickness.
Durability: Pest, mould, and water leakage resistance makes the structure long-lasting.
Precision: Uniform size and finish are ensured due to the factory-made blocks.
Manufacturing Process
The manufacturing of AAC blocks involves the following major steps:
Raw Material Preparation: Fly ash (or sand), lime, cement, water, and aluminium powder are measured out and mixed in a specific proportion.
Mixing and Pouring: Ingredients are mixed to form a slurry and poured into huge moulds. Aluminium reacts with lime, evolving hydrogen gas and forming a cellular structure.
Pre-curing: The mixture hardens and swells in moulds for a few hours, rising as dough does.
Cutting: When the mixture hardens a little, it is removed from the moulds and cut into blocks of required sizes with steel wires.
Autoclaving: The cut blocks are subsequently cured in a high-pressure steam chamber (autoclave) at approximately 180–200°C and 12 bar pressure for 8–12 hours. This treatment makes the blocks stronger by transforming calcium hydroxide and silicates into tobermorite crystals.
Drying and Packing: Cured blocks are then dried and packaged for transport.
Features and Purpose
AAC blocks are intended to perform structural as well as non-structural functions. Their main features are:
Eco-Friendly: Utilizes industrial waste (such as fly ash), lowers emissions because of reduced transportation load, and reduces site wastage.
Faster Construction: Big size and lower weight facilitate faster construction of the wall and simpler handling.
Energy Efficiency: Superior insulating capabilities lower the energy consumption of buildings.
Reduced Mortar Usage: Thin joint adhesives eliminate thick mortar beds, reducing cement and sand needs. #AACblocks
