THE APPLICATION POSSIBILITIES OF FLY ASH, SILICA FUME AND RECYCLED CONCRETE AGGREGATES IN SELF – COMPACTING CONCRETE

Abstract

The concept of sustainable development, which besides social and economic aspects includes energy – saving, environmental protection and the conservation of exhaustible natural resources, impose the use of recycled aggregates as a solution of two significant problems in the civil engineering. There is a lack of natural aggregates in urban areas and increasing of the distance between the sources of natural aggregates and construction sites, as well as the problem of removal and disposal of large quantities of concrete waste. Self – compacting concrete, being innovation in the field of concrete technology, contains a certain amount of powdered materials – fillers. There are various possibilities of selecting this component. If we used any of the industrial by – products, such as fly ash or silica fume, we would solve the problem of depositing these materials, and thus made concrete ecological material. The research subject presented in this paper are properties and technology of self – compacting concrete made with various mineral additives: fly ash and silica fume, wherein the aggregates used, are both natural and recycled aggregates, obtained by demolition of retaining wall, whose amount is varied in the concrete.