Blast-furnace slag (GBFS) and silica fume (SF) are produced as by-product from chemical industries with limited recycling facility. This paper represents an experimental study aimed to produce cementless binding material using both of sodium hydroxide (SH) and waterglass liquid (SSL) as alkaline activator. The alkaline activation of GBFS-SF has been studied by using electrical conductivity, FT-IR, DTA/TGA, XRD and SEM techniques. As the hydration time increases the amount of hydration products increase. The chemically combined water and combined slag contents increase with curing ages. SEM images showed the presence of C-S-H and (N,C)-A-S-H gel with low porosity. The alkali activated GBFS-SF pastes are more durable in 5% MgSO4 or 5% MgCl2 solution than ordinary Portland cement (OPC) up to 180 days. The total chloride and total sulphate contents decrease with alkali activated GBFS-SF due to the formation of hydrated products, which fill the available open pores, thereby inhibit Cl- or SO4 2- ions penetration; this effect leads to a decreased accessibility of Cl- or SO4 2- ions towards the more dense close structure with low capillary pore structure.