One of the possibilities how to activate fly ash in cement composites is to add calcium oxide as a chemical activator. This addition can improve pH of composites. Because fluidized bed combustion (FBC) fly ash contain around 15% of calcium oxide, we decided to add FBC fly ash into binder system of cement composite with classic fly ash.Three mixtures were designed. First one contain in binder system only cement and classic fly ash. In second and third mixture was part (25% resp. 50%) of classic fly ash replaced by FBC fly ash. Consistency, shrinkage, compressive strength and freeze-thaw resistance were tested. Microstructure was detected by XRD and TG analyses.