Steel-slag hydrated matrix is made of ground granulated blast furnace slag
powder and steel-making slag which is by-product of iron manufacturing. Alkali
activator is added if necessary. The cement is not required to produce the steelslag hydrated matrix. The leaching of heavy metal from steel-slag hydrated matrix is very little. This type construction material is called environmental conscious material in Japan. This research presented that the strength of steel-slag hydrated matrix depend on pH of steel-slag hydrated matrix after mixing. By controlling pH of steel-slag hydrated matrix after mixing, dispersion of strength become small and it can be stably made the same grade as cement concrete. It is also clear that the resistance to carbonation and steel rod corrosion of steel-slag hydrated matrix
has high performance for a long time by alkalinity of steel-making slag.