August 11th, 2007
“AAC is lightweight, about a fifth the weight of concrete.
“Michael has become the Pied Piper of AerBlock because he believes it is the perfect building material. It is light-weight, so it is easy to lift the blocks, and because of all the trapped air, it is a good thermal insulating and sound deadening material. Since it is masonry, it is completely fire proof and very durable, without harboring insects, rodents or mold. It is quite easy to build with and very versatile in the style of projects that can be accomplished. It is environmentally benign in that the material does not off-gas and can be installed as a breathable shell for habitation. The cost of building with AerBlock is comparable to many other building systems.
The process of manufacturing AAC is worth explaining. The basic ingredients are very simple: water, fine silica sand, Portland cement, lime, and a pinch of aluminum powder. These materials are mixed and placed into a large vat where a chemical reaction occurs that causes the mixture to expand like rising bread dough. Up to 80% of AerBlock is air. The curing process releases hydrogen gas, which is completely benign. Within a short while the dough can be sliced by pushing it through some taught wires.
The autoclaving part of the process begins when the slabs of dough are placed into a heated and pressurized tank for about half a day. During this curing time the material undergoes another chemical transformation and becomes Tobermorite (calcium silicate). At this point the mineral is completely inert and ready to be cut and shaped into a variety of forms useful for construction. “