AAC: Advantages & Sustainability

EASTLAND Autoclaved aerated concrete (AAC) panel is made with fine aggregates, cement, and an expansion agent that causes the fresh mixture to rise like bread dough. In fact, this type of concrete contains 80 percent air. In the factory where it is made, the material is molded and cut into precisely dimensioned units.

Cured AAC blocks or AAC panels of autoclaved aerated concrete are joined with thin bed mortar. Components can be used for walls, floors, and roofs. The lightweight material offers excellent sound and thermal insulation, and like all cement-based materials, is strong and fire resistant. In order to be durable, AAC requires some type of applied finish, such as a polymer-modified stucco, natural or manufactured stone, or siding. 

Advantages

• EASTLAND Autoclaved aerated concrete combines insulation and structural capability in one material for walls, floors, and roofs. Its light weight/cellular properties make it easy to cut, shave, and shape, accept nails and screws readily, and allow it to be routed to create chases for electrical conduits and smaller-diameter plumbing runs. This gives it design and construction flexibility, and the ability to make easy adjustments in the field.

• Durability and dimensional stability. A cement-based material, EASTLAND AAC resists water, rot, mold, mildew, and insects. Units are precisely shaped and conform to tight tolerances.

• Fire resistance is excellent, EASTLAND AAC has achieved a four-hour rating (actual performance exceeds that and meets test requirements for up to eight hours). And because it is noncombustible, it will not burn or give off toxic fumes.

• The light weight means that R-values for EASTLAND ALC are comparable to conventional frame walls, but they have higher thermal mass, provide air tightness, and as just noted, are not combustible. That light weight also gives a high sound reduction for privacy, both from outside noises and from other rooms when used as interior partition walls.

But the material does have some limitations. It is not as widely available as most concrete products, though it can be shipped anywhere. If it has to be shipped, its light weight is advantageous. Because it is lower strength than most concrete products or systems, in load-bearing applications, it must typically be reinforced. It also requires a protective finish since the material is porous and would deteriorate if left exposed.

Sustainability and Energy Considerations

EASTLAND Autoclaved aerated concrete offers both material and performance aspects from a sustainability perspective. On the material side, it can contain recycled materials like fly ash and rebar, which may help contribute to credits in LEED® or other green rating systems. Further, it incorporates such a large quantity of air that it contains less raw material per volume than many other building products. From a performance perspective, the system leads to tight building envelopes. This creates an energy efficient envelope and protects against unwanted air losses. Physical testing demonstrates heating and cooling savings of roughly 10 to 20 percent compared to conventional frame construction. In consistently cold climates, the savings may be somewhat less because this material has lower thermal mass than other types of concrete. Depending on the location of manufacturing relative to the project site, EASTLAND AAC may also contribute to local materials credits in some green building rating systems.