The binders known as blended or hybrid alkaline cements are obtained by alkali-activating cementitious blends in the Na₂O-CaO-SiO₂-Al₂O₃-H₂O system. The present paper discusses the results of alkali activating blends prepared were: binder BSLAG = 20 % OPC clinker + 80 % BFS; and binder BFA = 20 % OPC clinker + 80 % FA. The 2-day mechanical strength was over 15 MPa. The main reaction products were gels whose composition varied depending on the initial Ca content. In alkali-activated BSLAG cement they consisted of a mix of C‑S‑H/C‑A‑S‑H and in activated BFA cement of a mix of C‑A‑S‑H /(N,C)‑A‑S‑H.