Abstract: Kaolin was thermally activated with the addition of sodium hydroxide through solid reactions, and geopolymeric materials were prepared with the thermal activation products and steel slags through mixing, hydration and pressure molding.The surface bonding, mineralogy, and microstructure and morphology of the raw material and synthesized geopolymers were fully characterized by using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM).The geopolymeric material with 5wt.% kaolin thermal activation products and 95wt.% steel slags presents the best compressive strength，and the 3 d,7 d and 28 d compressive strength is 20，30 and 28.9MPa, reached the nonbearing wall material level MU20, MU25 and MU30, respectively.The bonding information shows that three dimensional Si(Al)—O structures of geopolymer were generated during the hydration reaction; calcium silicate in the steel slag was activated by alkali to form C-S-H structures and the other substance as filling materials well increased the compressive strength.

Key words: Geopolymer, Steel slag, Kaolin, Compression strength