BATMAN
08-31-2005, 11:32 PM
I just saw this on the Science Channel.
http://www.aacsinc.com/images/animatedgif.gif
Autoclaved Aerated Concrete (AAC) is a fully mature technology. It was developed in Sweden in the early 1900s. At that time it was observed that a mixture of lime and finely divided quartz could be foamed with aluminum powder and then autoclaved at 180°C to produce a lightweight, insulating, sound absorbing building material. The Germans refined the technology and have been producing lime-silica AAC for over 50 years under licensed trademarks such as Hebel and Ytong. Others, most notably the English and Eastern Europeans, soon substituted Class F fly ash for quartz and have been marketing fly ash derived AAC for almost as long (Celcon, Spirox). Although AAC is used for construction on every continent (>200 plants in 35 countries including Mexico), its use in the United States and Canada has been rather limited There are three major reasons for this. First, North America has an abundant supply of wood; thus wood-stud construction continues to be one of the most economical ways to construct residential housing. Second, and perhaps more salient, is the fact that AAC, as good as it is, is still a relatively new construction material that comes with a higher price tag than wood. As a whole, inhabitants of the United States and to a lesser extent Canada tend to move from job to job more frequently than their European/Asian counterparts. At this point in time, building a home out of AAC would cost significantly more than a similarly sized wood framed house, but on the other hand it would be relatively maintenance free and last considerably longer.
http://www.aacsinc.com/images/animatedgif.gif
Autoclaved Aerated Concrete (AAC) is a fully mature technology. It was developed in Sweden in the early 1900s. At that time it was observed that a mixture of lime and finely divided quartz could be foamed with aluminum powder and then autoclaved at 180°C to produce a lightweight, insulating, sound absorbing building material. The Germans refined the technology and have been producing lime-silica AAC for over 50 years under licensed trademarks such as Hebel and Ytong. Others, most notably the English and Eastern Europeans, soon substituted Class F fly ash for quartz and have been marketing fly ash derived AAC for almost as long (Celcon, Spirox). Although AAC is used for construction on every continent (>200 plants in 35 countries including Mexico), its use in the United States and Canada has been rather limited There are three major reasons for this. First, North America has an abundant supply of wood; thus wood-stud construction continues to be one of the most economical ways to construct residential housing. Second, and perhaps more salient, is the fact that AAC, as good as it is, is still a relatively new construction material that comes with a higher price tag than wood. As a whole, inhabitants of the United States and to a lesser extent Canada tend to move from job to job more frequently than their European/Asian counterparts. At this point in time, building a home out of AAC would cost significantly more than a similarly sized wood framed house, but on the other hand it would be relatively maintenance free and last considerably longer.