Autoclaved Aerated Concrete (AAC) has become, over the last decades, an important masonry material worldwide.
And that raises a question: how good is aerated concrete really?
What's Aerated Concrete?
Autoclaved Aerated Concrete is a cement-masonry precast product. It combines sand, cement, lime, water and a small amount of an expansionary agent, typically aluminum powder. AAC is mostly a wall building material. A green product?
We can say so. Aerated concrete is made with natural products, is recyclable and has a reasonable insulation value... Its big downside - from an environmental standpoint - is that its production involves a lot of energy (though less - 50% - than concrete products).
AAC is a bit like some insulation foams, embodying millions of tiny air cells that give the product a reasonable insulation value.
AAC has an insulation-value than bricks, concrete and other masonry products do not have: a typical 8 inch AAC block has an insulation value of about R-8 (which explains in part the increasing acceptance of AAC in wall assemblies).
AAC is a masonry construction material;
AAC should be viewed as an alternative to other masonry products, particularly in wall construction;
AAC has a reasonable inherent insulation value: 8 inch AAC block: R-8;
Besides their inherent R-value, AAC blocks are lightweight and easy to work.
ACC blocks can be easily cut to size by using a saw.
In regions where masonry construction is common, experienced bricklayers and carpenters should have no problems in working with AAC.
The practices, tools or knowledge (AAC surfaces should not be saturated before plastering or rendering, mortar should be properly chosen) associated with ACC are not complex or difficult to implement.
ACC blocks have a smaller thermal mass than other masonry products, and also a smaller compressive strength and structural resistance; hence the need of reinforced panels and blocks, for larger structures...
Unfamiliarity with the product and local market conditions are also significant disadvantages in some regions and parts of the world (North-America...).
ACC prices vary a lot, according to local market conditions.
Bottom line: pros and Cons
AAC should be viewed as an alternative to concrete and other masonry construction materials.
ACC doesn't replace insulation; in cold climates, or even in mixed and hot climates, the insulation value provided by ACC blocks is largely insufficient.
Its cost-effectiveness - compared to other masonry products - depends on market conditions or on the experience of local contractors and workers.