What is AAC Block & Why It’s the Future of Construction?

  • June 7, 2023

Autoclaved Aerated Concrete blocks are the superheroes of the construction world, offering a winning combination of strength, lightness, and impressive features. Made from a blend of cement, lime, water, and an air-entraining agent, these blocks have a secret power: tiny air pockets within the material that give it a lower density and lighter weight than solid concrete blocks. But don’t let their lighter stature fool you! AAC blocks are not lightweight when it comes to strength, boasting high compressive strength and fire-resistant nature. They also possess the ability to hush unwanted noise and create energy-efficient spaces, thanks to their thermal insulation properties. AAC blocks are known for their unique acoustic properties, making them an excellent choice for noise insulation and soundproofing. The cellular structure of AAC blocks, created through the process of autoclaving, provides them with exceptional sound absorption capabilities. These blocks effectively dampen sound vibrations, reducing the transmission of noise from one space to another. The porous nature of AAC blocks, combined with their density and composition, allows them to absorb and dissipate sound energy, resulting in quieter and more peaceful environments. Whether used in residential, commercial, or industrial construction, AAC blocks offer outstanding acoustic performance, creating spaces that are comfortable and free from unwanted noise disturbances.

AAC blocks save the day from residential homes to commercial complexes and industrial buildings by providing sturdy walls, floors, and roofs. These blocks embody the perfect balance of durability, safety, and sustainability, making them a top choice for construction projects of all sizes.

Table Of Contents:

  • What is AAC Block?

  • Standard size, weight, and density of the block

  • AAC block making process

  • Features of AAC Block

  • Difference between AAC blocks and clay bricks

  • AAC Block Installation guide

  • Advantages of AAC Blocks

  • Conclusion

What is AAC Block? 

Now, you might be wondering what exactly makes AAC blocks so unique?  Well, picture this: a building material that is not only lightweight but also incredibly strong, energy-efficient, and environmentally friendly. Sounds too good to be true, right? But AAC bricks deliver on all these fronts and more. Autoclaved Aerated concrete blocks are Made from a combination of cement, lime, sand, and water; these blocks undergo a unique manufacturing process that involves the introduction of air bubbles and curing under high-pressure steam. The result? A cellular structure with excellent thermal insulation properties, fire resistance, and acoustic insulation. The weight and Density of AAC blocks are not only a game-changer in terms of construction efficiency, but these blocks are also a sustainable choice that reduces the carbon footprint of buildings.


Beyond their functional advantages, AAC bricks offer a world of design possibilities.  The density and Lightweight attributes of Autoclaved Aerated Concrete blocks make them easy to handle, cutting down construction time and costs. In addition, it can be easily cut, shaped, and sculpted, giving architects and builders the freedom to create unique and intricate designs. Whether you’re constructing a residential building, a commercial complex, or even a soundproof recording studio, AAC bricks can meet a wide range of construction needs. And let’s not forget the economic benefits they bring – the reduced energy consumption and lower maintenance costs make AAC blocks an attractive choice for both homeowners and developers.


Standard Size, Weight, and Density of AAC Block

The size, weight, and density of Autoclaved Aerated concrete blocks are vital factors that significantly impact their performance and make them a preferred choice in the construction industry. Starting with size, the range of sizes available for AAC bricks provides flexibility and adaptability to meet diverse construction needs. Whether it’s load-bearing walls or non-load-bearing partitions, the varying dimensions of AAC blocks, such as length, height, and width, allow architects and builders to create structures that align with specific design requirements. AAC blocks mean versatility in size, ensure efficient space utilization, and enable architects to unleash their creativity while constructing aesthetically pleasing buildings.

The AAC bricks density and weight are equally crucial aspects that contribute to their popularity and practicality in construction projects. Aerated concrete blocks possess a relatively low-density thanks to their unique cellular structure formed by air bubbles within the blocks. This lower AAC block density makes the blocks lightweight and enhances their thermal insulation properties. By reducing heat transfer, AAC blocks help maintain comfortable indoor temperatures, reducing the need for excessive heating or cooling. Moreover, the lightweight nature of Aerated blocks simplifies handling, transportation, and installation, saving time and labor during construction. Their reduced weight also allows for easier maneuverability on construction sites, increasing efficiency and cost-effectiveness in building projects. Here are some details on the size, density, and weight of AAC blocks:


Size of AAC Block: 

AAC blocks come in a range of sizes to accommodate various construction needs. The standard sizes of AAC blocks mean they typically vary in length, height, and width, providing versatility in design and construction.

For example, the length of AAC bricks can range from 8 inches to 24 inches, while the height can vary from 4 inches to 12 inches. Additionally, the width of AAC blocks can range from 2 inches to 12 inches. These dimensions allow for easy handling, cutting, and installation, making AAC blocks suitable for both load-bearing and non-load-bearing applications. The varied sizes of AAC blocks offer flexibility to architects, builders, and homeowners, enabling them to create structures that meet specific requirements and design aesthetics.


Size in mm
    ► 600mm (L) x 200mm(W) x 75mm (D)
    ► 600mm(L) x 200mm (W)x100mm (D)
    ► 600mm (L)  x 200mm (W) x125mm (D)
    ► 600mm (L)  x 200mm (W) x150mm (D)
    ► 600mm (L)  x 200mm (W) x200mm (D)
    ► 600mm (L) x 200mm (W) x225mm (D)
    ► 600mm (L)  x 200mm (W) x250mm (D) 
  Size in inch
    ► 24’’ (L)  x 8” (W)  x 3”  (D)
    ► 24” (L) x 8” (W)  x 4” (D)
    ► 24” (L)  x 8” (W)  x 5” (D)
    ► 24” (L)  x 8” (W)  x 6” (D)
    ► 24” (L)  x 8” (W)  x 8” (D)
    ► 24” (L)  x 8” (W)  x 9” (D)
    ► 24” (L) x 8” (W)  x 10” (D)


Weight of AAC Block:

AAC blocks are known for their relatively low density, typically ranging from 550 kg/m³ to 850 kg/m³. This low density is achieved by incorporating air bubbles into the concrete mixture during the manufacturing process. The result is a cellular structure within the blocks, which reduces their weight and provides them with excellent insulation properties. The low density of AAC blocks size makes them lightweight and easy to handle, transport, and install, saving time and labor during construction. Additionally, the cellular structure contributes to their thermal insulation capabilities, making them energy-efficient and conducive to maintaining comfortable indoor temperatures. Overall, the density of Autoclaved Aerated concrete blocks plays a crucial role in their versatility, performance, and sustainability in various construction applications.


AAC Block weight Approx
    ► 24” (L)  x 8” (W)  x 3” (D) = 6 kg
    ► 24” (L)  x 8” (W) x 4” (D) = 8 kg
    ► 24” (L) x 8” (W)  x 5” (D) = 10 kg
    ► 24” (L)  x 8” (W) x 6” (D) = 12 kg
    ► 24” (L)  x 8” (W)  x 8” (D) = 16 kg
    ► 24” (L)  x 8” (W) x 9” (D) = 18 kg
    ► 24” (L)  x 8” (W)  x 10” (D) = 24 kg


Density of AAC Block: 

The density of AAC blocks , typically ranging from 550 kg/m³ to 850 kg/m³, plays a crucial role in their performance and suitability for construction. Achieved through the incorporation of air bubbles, the low density of AAC blocks makes them lightweight, facilitating easy handling, transportation, and installation on construction sites. Despite their reduced weight, Autoclaved aerated concrete blocks density is such that it maintains strength and structural integrity. Furthermore, the cellular structure resulting from their density enhances their thermal insulation properties, contributing to energy efficiency and comfortable indoor temperatures. Additionally, the lower density of AAC blocks provides acoustic insulation, reducing sound transmission and creating quieter living or working spaces. Overall, the thickness of AAC bricks sizes strikes a balance between weight, strength, thermal insulation, and acoustic properties, making them an ideal choice for diverse construction projects.

AAC blocks

AAC block making process

The making process of AAC (Autoclaved Aerated Concrete) blocks involves several key steps. Here is a brief overview of the process:


1. Raw Material Preparation:

 The primary ingredients for AAC blocks include cement, lime, fly ash, water, and an aerating agent. These materials are carefully measured and mixed to form a slurry.

2. Mixing and Formation:

 The slurry is poured into molds, which can be in various sizes and shapes, such as blocks or panels. The slurry undergoes a chemical reaction due to the aerating agent, producing gas bubbles that give AAC its cellular structure.


3. Cutting and Pre-Curing: 

After the slurry is poured into the molds, it is left to set and partially cure. Once the blocks are firm enough, they are cut into desired sizes using wire-cutting machines. The cut blocks are then stacked and arranged on racks for pre-curing.


4. Autoclaving: 

The pre-cured blocks are loaded onto autoclave racks and transferred into an autoclave chamber. In the autoclave, the blocks undergo a high-pressure steam curing process. This process promotes further chemical reactions, resulting in the formation of stable and durable AAC blocks. The autoclaving process typically takes several hours.


5. Cooling and Finishing: 

After the autoclaving process, the blocks are slowly cooled down before being removed from the autoclave. Once cooled, they are inspected for quality, and any necessary finishing touches, such as trimming or surface treatment, are applied.


6. Packaging and Distribution: 

The final step involves packaging and preparing the AAC blocks for distribution to construction sites or retailers.

The precise details and variations in the manufacturing process may vary between manufacturers, but the overall steps remain consistent. The result is a lightweight, eco-friendly, and versatile building material with excellent thermal insulation and fire-resistant properties.


Features Of AAC Block: 

AAC blocks possess a variety of features that contribute to their popularity and practicality in construction:

1. Lightweight: 

Autoclaved Aerated Concrete blocks are significantly lighter in weight and density compared to traditional concrete blocks, making them easier to handle, transport, and install. This reduces labor and equipment requirements during construction, saving time and cost.

2. Thermal Insulation: 

The cellular structure of AAC blocks provides excellent thermal insulation properties. They help regulate indoor temperatures, reducing the need for excessive heating or cooling and contributing to building energy efficiency.

3. Strength and Durability:

AAC blocks exhibit remarkable strength and durability despite their lightweight nature. They have high compressive strength, making them suitable for load-bearing walls and structures. AAC blocks also have excellent resistance to fire, pests, and weathering.

4. Sound Insulation: 

The cellular structure of AAC bricks contributes to their acoustic insulation properties. They effectively reduce sound transmission, creating quieter indoor spaces and enhancing occupant comfort.

5. Sustainable and Eco-friendly:

AAC bricks are made from environmentally friendly materials such as cement, lime, sand, and water. Their manufacturing process generates minimal waste, and they can be recycled. Additionally, the energy-saving properties of AAC bricks contribute to reduced carbon emissions and a lower environmental impact.

6. Design Flexibility: 

AAC bricks can be easily cut, shaped, and sculpted, allowing architects and builders to create intricate designs and customized structures. They offer flexibility in construction and architectural creativity.


7. Moisture and Mold Resistance:

AAC blocks are resistant to moisture absorption, preventing the growth of mold and mildew. This feature contributes to healthier indoor environments and reduces the need for maintenance and repairs.


Difference Between AAC Blocks & Clay Bricks: 

AAC bricks and clay bricks are two commonly used construction materials, and they differ in several key aspects:


1. Composition: 

AAC blocks are made from a mixture of cement, lime, sand, and water, along with an expanding agent that creates air bubbles during the manufacturing process. On the other hand, clay bricks are made primarily from natural clay and shale, which are shaped and then fired in a kiln.


2. Weight:

AAC blocks are light in weight and density compared to clay bricks. The cellular structure of AAC blocks, created by incorporating air bubbles, reduces their density and weight. In contrast, the firing process makes clay bricks denser and heavier.


3. Thermal Insulation:

AAC blocks have excellent thermal insulation properties. The air-filled pores size within the blocks provide effective insulation, helping to regulate indoor temperatures and reduce energy consumption for heating and cooling. Clay bricks have lower thermal insulation properties compared to AAC blocks.


4. Strength:

AAC blocks have high compressive strength, making them suitable for load-bearing walls and structures. They exhibit good structural size integrity and can withstand heavy loads. Clay bricks also have good power but are more prone to damage under extreme loads or seismic conditions.


5. Sound Insulation: 

AAC blocks provide better sound insulation compared to clay bricks. The cellular structure of Autoclaved aerated concrete blocks reduces sound transmission, creating quieter indoor spaces. Clay bricks offer some sound insulation but are less effective than AAC blocks.


6. Construction Efficiency: 

AAC blocks are larger than clay bricks, speeding up construction as fewer blocks are needed to cover a given area. Additionally, the lightweight nature of AAC blocks makes them easier to handle and install. Clay bricks require more labor and time for construction due to their smaller size and heavier weight.


7. Sustainability: 

Both AAC blocks and clay bricks have environmentally friendly aspects. Autoclaved aerated concrete blocks use a higher proportion of recycled materials, generate less waste during manufacturing, and have better energy efficiency in buildings. Clay bricks are made from natural clay, a renewable resource, but their manufacturing process involves firing, which consumes energy and releases carbon emissions.

AAC Block Installation Guide: 

It’s essential to consider factors such as project requirements, cost, local availability, and desired characteristics when choosing between AAC blocks and clay bricks for a construction project.

Installing AAC blocks requires careful planning and precise execution to ensure a successful construction project. Here is a general guide for the installation process of AAC blocks:


  1. Preparation:
  • Ensure the foundation is properly leveled and cured before starting the installation.
  • Determine the layout and mark the positions of walls or partitions using chalk lines.
  • Prepare the necessary tools and materials, including mortar mix, trowels, spirit levels, and a cutting tool for AAC bricks.


  1. Mortar Mixing:
  • Follow the manufacturer’s instructions to prepare the mortar mix, which is typically a combination of cement, sand, and water.
  • Use a mortar or mechanical mixer to achieve a consistent and uniform mixture.
  • Maintain the right proportion of ingredients to achieve the desired mortar consistency for AAC block installation.


  1. Laying AAC Blocks:
  • Use a trowel to apply a thin layer of mortar on the foundation or the lower course of blocks.
  • Place the first AAC block gently onto the mortar bed, ensuring it is level and plumb using a spirit level.
  • Apply mortar to the side and end surfaces of subsequent blocks before placing them adjacent to the previous block.
  • Use a rubber mallet to tap the blocks into position lightly, ensuring they are tightly fitted with minimal gaps.


autoclaved aerated concrete

  1. Cutting AAC Blocks:
  • Measure and mark the desired length or shape on the AAC block using a marker or chalk.
  • Use a cutting tool designed explicitly for AAC blocks, such as a handsaw or an AAC block cutter.
  • Carefully cut the block along the marked line, applying even pressure to ensure a clean and precise cut.
  • Remove any loose debris or particles from the cut block before placing it in position.


  1. Vertical Reinforcement:
  • For load-bearing walls, incorporate vertical reinforcement by inserting steel bars or rebar into the mortar joints at regular intervals per engineering specifications.
  • Ensure the reinforcement is securely embedded in the mortar to provide structural strength and stability.


  1. Horizontal Reinforcement and Bond Beams:
  • Install horizontal reinforcement, such as steel bars or mesh, at the specified levels within the AAC wall to enhance stability and load-bearing capacity.
  • Incorporate bond beams, horizontal reinforced concrete beams, at the top of walls, or specific intervals as required by the structural design.


  1. Curing and Finishing:
  • Allow the mortar to cure and dry as per the manufacturer’s instructions. Protect the walls from excessive moisture or extreme weather conditions during curing.
  • After the mortar has fully cured, finish the AAC block walls as desired, such as plastering or applying finishes like paint or cladding.


It is safe to refer to the manufacturer’s guidelines and consult a qualified engineer or construction professional for specific instructions and recommendations based on the project requirements. Adhering to proper installation techniques ensures the durability, stability, and performance of the AAC block construction.


Advantages of AAC Blocks: 

Autoclaved Aerated Concrete blocks offer several advantages that make them a preferred choice in the construction industry:


1. Sustainability: 

AAC blocks are environmentally friendly and sustainable construction materials. They use a high proportion of recycled materials, generate less waste during manufacturing, and have a lower carbon footprint than traditional concrete blocks. Additionally, AAC blocks are non-toxic and do not release harmful gases or substances, contributing to healthier indoor environments.


2. Design Flexibility:

AAC blocks can be easily cut, shaped, and sculpted, allowing architects and builders to create intricate designs and customized structures. They offer flexibility in construction, enabling the realization of various architectural styles and design aesthetics.


3. Speed of Construction: 

The larger size of AAC blocks, combined with their lightweight nature, allows for faster construction than traditional brick or concrete block walls. This reduces construction time and costs, making AAC blocks cost-effective for building projects.


4. Resistance to Moisture and Mold: 

AAC blocks are resistant to moisture absorption, preventing the growth of mold and mildew. This feature contributes to healthier indoor environments, reduces the risk of structural damage, and minimizes the need for maintenance or repairs.

Overall, the advantages of AAC blocks, including their lightweight nature, thermal insulation, strength, durability, sound insulation, sustainability, design flexibility, and resistance to moisture and mold, make them a versatile and sustainable choice for a wide range of construction applications.



In conclusion, Autoclaved Aerated concrete offers numerous advantages, making them an attractive option for construction projects. Their lightweight nature allows easier handling and installation, reducing labor and equipment costs. The excellent thermal insulation properties of AAC bricks contribute to energy efficiency and comfortable indoor environments. Additionally, AAC blocks exhibit impressive strength, durability, and superior sound insulation capabilities. The sustainable characteristics of AAC blocks, including recycled materials and reduced carbon footprint, align with the growing emphasis on environmentally friendly construction practices. The design flexibility and resistance to moisture and mold further enhance their appeal. Overall, AAC blocks provide a versatile, efficient, and sustainable solution for modern construction needs.




By Eishita Rambhiya

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