In construction are still mostly used materials with a negative impact to environment. Extraction of stocks natural resources is limited and the energy intensity of their processing is very high. Composites based on alkaline activation could be a partial alternative of these materials. These composites, based on alkali-activation of secondary products of metallurgical and energy industry achieve higher strengths then currently used binders and are also characterized by higher resistance. The paper deals with the possibility of use cement kiln dust and fly ash after denitrification by SNCR method as an admixture in alkali activated materials. In experiment, effect of using cement kiln dust and fly ash after denitrification by SNCR method on selected physical-mechanical properties and frost resistance of prepared mixtures was studied.