AAC Cement Blocks – Benefits, Applications & Installation

In today’s modern construction industry, selecting the appropriate building material is essential. In the fast-paced modern construction industry, AAC cement blocks are set to revolutionise the building industry. At a rapid pace, they are replacing traditional blocks as a contemporary building material. Using wood as a building material may cause termite damage, be flammable, and decompose. Civil and industrial construction widely use this type of cement block rather than traditional blocks for quick construction. In this article, we will see the key benefits, applications, manufacturing process, and installation of AAC cement block.

What is an AAC Cement Block?

AAC (Autoclaved Aerated Concrete) cement blocks are light building materials that are made in a factory. They are created from a mix of fly ash, cement, lime, gypsum, and a special ingredient that helps them expand. This process makes the blocks have lots of small holes inside, making them lightweight and strong. ​Because of these qualities, AAC blocks can be used for many different types of construction projects.

Composition of AAC Cement Block

Fly ash, cement, lime, gypsum, and an aeration agent are the ingredients of autoclaved aerated concrete, or AAC. Because the blocks are porous and lightweight, they must be handled carefully to prevent breakage and shielded from the weather. In a perfect setting, a dynamic AAC cement block risesslowly. Just as the dough rises, the AAC cement block rises in a warm and consistent environment. After completing the drying process, the mixture consists of 80% air in it.

Then the mixture is moulded, autoclaved under tremendous pressure, and cut into specific shapes and dimensions. Now, an eco-friendly product is ready to build your construction project by adding a perfect expansion agent as an add-on. It is comparatively three times lighter than the traditional red bricks.

Key Benefits of Using AAC Cement Blocks

Did you know? AAC cement blocks are an excellent alternative and sustainable modern building material compared to traditional blocks.​ However, with its unique properties, we have to recognise the top benefits of using AAC cement blocks in civil and industrial construction processes.

• Reusable and Renewable Products

Ideally, eco-friendly products are made from recycled materials that reduce the usage of new resources. The production methods of these materials include less emission, reduced water and energy usage, and limited waste.

• Lightweight and Compact

These blocks are substantially lighter than conventional red bricks, which lowers the building structure’s weight (or “dead load”). Because the lower load places less strain on the foundation and supporting components, this feature enables engineers and architects to construct higher buildings without sacrificing stability.

• Heat Protection and Energy Savings

The block’s tiny air spaces serve as thermal insulators. AAC cement blocks are dsigned to keep interior temperatures comfortable, minimise radiation, and use less energy, especially for heating and cooling.

• Acoustic Performance: 

These blocks are perfect for buildings that need quiet spaces, including hospitals, schools, hotels, and workplaces, because of their porous construction, which absorbs sound and reduces noise.

• Fire Resistant: 

Due to its exceptional fireproof properties, it can tolerate high temperatures (up to 1600°C). As the fire resistance property is essential for building constructions like commercial and residential buildings, it can withstand exposure to high temperatures for up to six hours.

• Seismic Resistant: 

The seismic effect on buildings can be reduced for less mass structures because of less inertia. This results in lower the chances of building damage. Because of its lightweight properties, it drastically reduces the mass of the sturdy building.

Applications of AAC Cement Blocks in Construction

The many use and structural advantages of AAC Cement Blocks make them a popular option in building. Their various applications are as follows:

• Building Houses and Apartments: AAC blocks are used to build residential houses and apartments for their solidity and endurance.
• Warehouses & Industrial Facilities: Perfect for constructing factories and storage spaces where robustness and load-bearing capacity are essential.
• Building Educational and Healthcare Structures: Schools and hospitals can be built using these blocks for their sturdiness and longevity.
• Infrastructure Projects: Massive structures like bridges, tunnels, and other steady infrastructure projects may use these blocks for their hardness and durability.
• Industrial and Commercial Structures: Industrial and commercial spaces can be constriucted quickly by using AAC cement blocks.

The Manufacturing Process of AAC Cement Block

Do you want to know how AAC blocks are made? The below steps will help you to understand the process of making AAC cement blocks in detail.

• Step 1: Preparation of Raw Material 

Processing the raw materials is the first step in creating AAC blocks:

Cement: For consistent quality, 53-grade Ordinary Portland Cement (OPC) is needed. To avoid batch fluctuations, plant-supplied cement is preferred.

Fly ash and Lime Stone Powder: Fly ash is used as a slurry. Another necessary ingredient is limestone powder, which is either ground on-site or purchased already from vendors.

Gypsum: A common building material used in the manufacture of AAC blocks.

• Step 2: Mixing and Dosing 

Dosing and mixing are the next steps in the production of AAC blocks once the basic ingredients have been prepared. The outcome of this process is influenced by its quality. Here is a summary:

Ratios of ingredients: 

Fly Ash, Lime, Cement, and Gypsum = 69:20:8:3.

0.08% of the total dry components are aluminium powder.

Ratio of water: 0.60 to 0.65

The procedure employs a dosage and mixing unit and takes approximately 5.5 minutes:

The following materials are measured into different containers: fly ash, lime, cement, and gypsum.

Each ingredient is released into a mixing drum once the proper weight has been achieved.

A smaller feeder is used to add aluminium powder individually.

The mixture is then put into moulds. The dosing and mixing cycle is fully automated, with minimal human involvement, to prevent material solidification and maintain a continuous flow.

Step 3: Casting, Rising, and Curing

To avoid sticking, the prepared raw material combination is placed into greased moulds, which are usually 4.2 x 1.2 x 0.65 meters. Aluminium in the combination expands up to three times its initial size as it combines with calcium hydroxide and water, releasing hydrogen gas in the form of tiny bubbles (2–5 mm) which gives insulating and lightweight properties. Depending on the temperature and material combination, the mixture (also known as “green cake”) is allowed to cure for one to four hours after expanding. Once firm, it is cut to the required sizes.

The blocks are strengthened and set by high-pressure steam (800–1200 kPa) at 180°C during the final curing process in an autoclave, a sizable steel chamber.

Step 4: Demolding and Cutting

The green cake is prepared for demolding and cutting when it reaches the required strength. Following pre-curing, a crane raises the mould for demolding. The demolding and cutting procedures can differ based on the technology employed, although the preparation, mixing, and casting of raw materials are generally identical.

The green cake is taken out of the mould and transferred to the cutting line using a variety of mould types and techniques, which are primarily categorised as tilt cake and flat cake.

How to Install AAC Cement Blocks?

A brief explanation for installing AAC blocks can be discussed below:

The debris can be removed from the area of the foundation and dug to the necessary depth of drainage. To establish a level foundation, compact the dirt, add geotextile fabric for support, and pour concrete.

Planning the Layout: Measure and mark the foundation’s wall configuration. Align using chalk or string, taking into account window, door, and fixture openings.

Use mortar by combining cement, sand, and water. Evenly distribute it around the foundation, allowing room for reinforcement if necessary.

AAC block placement involves starting in a corner, placing blocks on the mortar bed, and then lightly covering each block with mortar. Use a spirit level to make sure everything is aligned and level.

Joint Reinforcement and Filling: Apply mortar to joints and install.

Maintenance and Care for AAC Cement Blocks

• To get rid of grime, use a soft brush or low-pressure water to clean AAC blocks. AAC blocks cannot withstand high-pressure washes and rough or scratching cleaning methods.

• To guard against moisture and weathering, repaint or waterproof blocks every few years using high-quality materials.

• To avoid more problems, regularly inspect for damage, water seepage, or cracks and make repairs as soon as possible.

• To avoid water buildup around the foundation, which over time may erode it, make sure drainage is effective.

• To find any damage or settling of the foundation, regular inspection will help.

• Proper insulation and ventilation facilities may reduce moisture and increase energy efficiency.

• To preserve stability and increase longevity, reinforce structures in seismically active locations or as needed.

• To avoid damage, make sure downspouts divert water away from the foundation and clean gutters regularly.

• For difficult maintenance or repair issues, seek the advice of professionals (such as architects, engineers, or contractors).

• To guarantee the AAC block structure’s long-term endurance, take immediate care of any maintenance requirements.

Conclusion

As the construction industry is growing rapidly by using renewable and recyclable materials in building construction, AAC cement blocks are performing well in that category. Companies are also moving fast with the growing market by increasing the production of AAC cement blocks. These blocks have advantages over conventional materials, and builders and developers are realising these long-term benefits. 

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