Parameters Influencing the Stability of Foamed Concrete

Abstract

Foamed concrete is a versatile lightweight concrete that is finding increasing use in various application areas. A major concern with foamed concrete is its stability. Air voids can become unstable during production and placement or after placement of foamed concrete during the time when it is plastic and setting has not occurred. Because of the scarcity of information on foamed concrete stability, an experimental study was carried out to yield further information in this regard. Mixtures with foam contents from 2 to 9% were studied. The effects of using varying amounts of a plasticizing admixture in increasing the workability of the base mixture and its influence on stability were also studied. Although it was possible to produce and cast mixtures with up to 9% foam content, it was found that mixtures with foam contents of approximately 65% and higher became unstable some time after casting. Increasing the workability of the base mixture by using a plasticizer significantly improved the stability of foamed concrete mixtures and allowed achieving stability even at very high foam contents.