PRODUCTION OF FOAMED CONCRETE WITH HIGH CALCIUM FLY ASH

Foamed concrete is used extensively for the construction of floors or roofs because of its low weight and thermal insulation properties. Rich in cement mixtures are commonly used for its production. In this paper the findings of a project funded by the Greek Secretarial of Research and Technology and the MONOTHERM Industry are presented. What was studied was the partial replacement of the cement with a high calcium fly ash which exhibits pozzolanic and hydraulic properties for financial and technical benefits. A series of mixtures were produced, in which the Portland cement (PC) was substituted for fly ash at different percentages. Mechanical properties and shrinkage deformations which are some of the most important parameters for the performance of foamed concrete were measured. Based on the results, it seems that fly ash can replace Portland cement in foamed concrete up to 40 - 60% with an improvement in strength compared with the conventional (reference) PC foamed concrete. Besides, the fly ash addition seems to contribute to better cohesion of the fresh mixture and lower early plastic shrinkage deformations.