Q.: Can ordinary household detergents be used to entrain air in concrete? The manufacturer of a small curb-and-gutter machine we bought recommends using a detergent to produce air-entrained concrete.
A.: Air-entraining agents belong to a class of chemicals called surfactants, of which detergents are one category. Thus, many soaps and detergents could serve as air-entraining admixtures in concrete. However, not all are equally effective, and the critically important properties of the entrained-air system depend on the nature of the surfactant used (see reference).
Commercially produced air-entraining agents are relatively inexpensive, so we recommend using a product made especially for concrete. Use a portable mechanical mixer to mix the concrete, and check the air content with a pressure-type meter to be sure it's at the desired level.
W.L. Dolch, "Air-Entraining Admixtures," Concrete Admixtures Handbook, Noyes Publications, Park Ridge, N.J., 1995, p. 520.