AAC Blocks vs Concrete blocks: A Comparative Analysis

AAC blocks and concrete blocks are widely used across construction projects, enabling developers to transition from red clay bricks seamlessly. Both AAC blocks and concrete blocks provide unique advantages to builders, while offering high workability on site. By comparing their chemical structure, properties, costs, environmental impact, and storage requirements, we can understand when to use AAC blocks and when to leverage concrete blocks for our projects.

Raw materials used

Concrete blocks are developed through a mixture of Portland cement, water, sand, and gravel, and can be manufactured in a range of different dimensions. They are precast (formed and hardened) before arriving on the job site, and are available in solid, hollow, and cellular forms.     

AAC blocks are manufactured with fly ash, cement, lime powder, cement, gypsum, aluminium, and an aeration agent. The autoclaving process ensures that AAC blocks emerge with the desired compressive strength and dimensions. Air constitutes about 80-85% of their composition by volume.

Technical properties

Let us compare the technical differences between AAC blocks and solid concrete blocks.

Compressive strength – Solid concrete blocks offer a compressive strength of 4-5 N/mm², while AAC blocks provide 3-4 N/mm² of strength.  

Weight – Solid concrete blocks can weigh between 17-19 kgs for 400 mm x 200 mm x 100 mm blocks. AAC blocks can weigh between 9-10 kgs for the same dimensions. Lesser number of AAC blocks are required per square meter when compared to solid concrete blocks.

Dry density – Solid concrete blocks offer a dry density of 1800 kg/m³ - 2500 kg/m³. AAC blocks are lightweight and have a dry density of around 550 – 650 kg/m³ but can extend to 1000 kg/m³. This makes AAC blocks more flexible and versatile to use.

Fire resistance – Both solid concrete blocks and AAC blocks can provide fire resistance of 4 hours for thick walls, based on the brand.

Variation in size – Concrete blocks are manufactured with 5mm (+-) and 3 mm (+-) in length and height/width variation. AAC blocks are developed with a more precise 1.5 mm (+-) in dimensional variation.

Sound insulation – Concrete blocks can provide exceptional sound insulation of 50dB, while AAC blocks provide 40-45 dB for 200mm thick walls.

Termite resistance – Both concrete blocks and AAC blocks provide superior termite resistance, thereby enhancing lifespan.   

Colour – Concrete blocks are light grey in colour, and AAC blocks are grey in colour.

Key benefits delivered

Both AAC blocks and concrete blocks offer superior utilization, due to their inherent structure and technical properties. They ensure negligible breakage or wastage and can be used across a range of applications. AAC blocks are also available at any time of the year.

AAC blocks are highly environmentally friendly as they are manufactured via fly ash and other non-toxic materials. The raw materials used during the manufacturing of AAC blocks are also recycled for complete sustainability. This enables the construction value chain to be greener as a result.

As AAC blocks are lightweight and offer high compressive strength, they are easier to work with and transport to project sites. They consume less mortar and can be easily stored without special containment requirements. In the case of concrete blocks, site managers need to ensure minimal contact with moisture for optimal storage.      

AAC blocks also offer cost savings in terms of steel and concrete savings, while also reducing the overall foundational load. They require lesser long-term maintenance, which is why they help lower upkeep costs for buildings as well. AAC blocks are also more resistant to seismic forces as well.                                            

Use-cases for each        

Solid concrete blocks can be used for load-bearing and non-load bearing walls, and can be used for retaining walls, garden areas, fireplaces, etc. as well. They can also be used extensively for foundations and basement walls and are ideal for medium-scale projects. As concrete blocks are available in different types and formats (lintel, stretcher, paver, etc.), developers can use them for a wide range of applications.     

AAC blocks can also be used for load-bearing and non-load bearing walls and are recommended for high-rise structures due to their lightweight and durable properties. The thermal conductivity of AAC blocks is lower, making them perfect for interior walls and residential construction projects. They also reduce the energy cost of HVAC and can help drive long-term savings. Buyers finding the best AAC blocks price online can browse the extensive portfolio of AAC blocks brands available on BuildSupply.

In conclusion

Procurement managers can simplify the acquisition of AAC blocks and concrete blocks by analysing their unique benefits, technical properties, and use-cases. They can accurately capture the total cost of AAC blocks and concrete blocks, as the blocks are not susceptible to breakage and can be fully utilized. BuildSupply, an industry platform for price discovery and procurement, offers the best range of AAC blocks and concrete blocks for optimal acquisition and cost-savings. Buyers can review leading brands, float RFQs, and track all orders seamlessly through the platform directly.