The effect of high fly ash content on the compressive strength of foamed concrete

Abstract A study has been undertaken to investigate the effects, on the properties of foamed concrete, of replacing large volumes of cement (up to 75% by weight) with both classified and unclassified fly ash. This paper reports only on the results of the compressive strength of concretes cured under sealed conditions and shows that up to 67% of the cement could be replaced without any significant reductions in strength. There appears to be little difference in the performance of the ungraded and the graded fly ashes used in this investigation. Equations based on effective water/cement (w/c) ratio and binder ratio have been developed to predict the strengths up to 1 year, of foamed concretes made with densities ranging from 1000 to 1500 kg/m3. The calculated results compare well with the experimental results.