11-09-2005, 11:33 PM
Modern day concrete is air entrained using not fat, but a soap that can produce a bubble of a given size in an alkaline environment. Most air-entrained concrete contains about 4 to 7 percent air by total volume of concrete.
http://www.lmcc.com/news/spring2004/spring2004-08.asp
http://www.lmcc.com/news/spring2004/spring2004-08.asp

