How to Make AAC Blocks?
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How to Make AAC Blocks?

Views: 283     Author: Site Editor     Publish Time: 2022-04-26      Origin: Site Inquire


Currently, many buildings are being brought up due to the increasing rate of urbanization and population growth. It has led to the rising demand for building materials like AAC blocks.

In the 1920s, Johan Axel Eriksson, a Swedish architect, came up with the AAC. His main goal wasto develop an alternate building material lice wood. He wanted a material with a solid structure and good thermal insulation. AAC blocks are the common building material in Europe, plus it is hastily growing worldwide.

This article has the necessary information about AAC blocks plus how they are made, and l encourage you to continue reading.

What are AAC blocks?

Autoclaved Aerated Concrete (AAC) is an environmentally friendly and proficient  green construction material used for industrial, residential and commercial construction. It is a non-toxic, perusable, renewable, recyclable, and porous building material. The AAC blocks are well fit to build tall buildings and those with high-temperature variations.

What are the ingredients of AAC blocks?

  • Aluminum powder-0. 07%

Aluminum powder is used to make ACC it is used to cause an expansion in the mixture.

  • Sand

These are the maximum particles of crushed stones that can pass through a sleve of 4. 75mm.

  • Limestone-8%

Limestone is inclusive of calcite aragonite. It is a necessity for the production of AAC blocks.

  • The cement, which is grade 53 of OPC-33%

Cement is used when building to harden, plus it bids other building materials together.

  • Fly ash-59%

Fly ash is usually from the end products of powerplants. It offers sound absorption, fire resistance, and thermal insulation.

The manufacturing process of AAC block

AAC blocks are essentially made from sand, aluminum powder, water, cement, and fly ash. It isformed by adding the right amounts of aluminum powder plus other extracts into the slurry of silica or fly ash lime, cement, and water.

1. Dosing and Mixing

Here, a dosing and mixing unit is introduced to ensure the right amount of mixture is used toproduce the AAC blocks. Here, mixing and pouring take about 5-6 minutes. The slurry of sand or fly ash is usually pumped into another container until thedesired weight is attained.

This process is similarly conducted to cement and lime powder in separate containers. After filling all the required amounts in their separate containers, the control system pours them into a mixing drum.

The mixture is then churned for a precise time before pouring into the mold. The dosing unit is then used to pour the mixture as per the set precise quantities is molds. The dosing and mixing process is constantly carried out to prevent the hardening of the mixture.

2. Molding, Rising, and Pre-curing

The comcrete mixture is then poured into the moldto give the block its standard size. Molds are usually in various sizes, and they vary in their installed capacity. Molds are usually layered with thin layers of oil to prevent the green cake from sticking to the molds before casting. Mesh or steel bars are aIso patin a mold to strengthen the AAC products mechanically.

Hydrogen gas is produced when the aluminum powder is mixed with silica, and it helps in the expansion of the original volume of the mixture. This aeration process leads to the insulation properties and the lightweight of the AAC blocks. After the rising process is done, the green-cake is left to settle and cure for about 60-240 minutes.

The rising process usually depends on the weather conditions and the mixture of the raw materials. The autoclave temperature is usually at 190*Celsius and pressure of about 8 to 12 bars. This pressure and steam react with calcium hydroxide and sand, which forms calcium silicate hydrate. It provides and enhances strength on the AAC block.

3. Demolding and Cutting

After the green cake has attained its cutting strength, it is set to be de-molded and cut as per the desired requirements. The mold is then cut into small portions, and its wastes are recyclable. The cutting process is crucial as it determines the dimensional accuracy plus the quantity of rejection of the AAC block.

Advantages of AAC block

  • It saves energy and costs during transportation.

  • It saves labor expenditures due to its lightweight.

  • It can’t be affected by termites like other building materials like timber.

  • It helps in reducing the generated waste products in the environment.

  • It has a lesser surrounding effect due to the use of fly ash.

  • It is biodegradable plus a fire-resistant building material.


AAC blocks are the best building materials to consider using when building. AAC blocks consist of solid structures and good thermal insulation properties. It is an eco-friendly material made ofindustrial waste products. It is non-toxic, perusable, renewable, recyclable, and porous building material, and they are the best fit for building tall buildings and houses with variations in high temperature.