Abstract: A superfine slag powder (SP) made from granulated blast furnace slag incorporating activators by using special milling technique, was used as supplementary cementitious material in high performance concrete (HPC), replacing part of the mass of normal Portland cement. The effects of the SP on the workability, mechanical and crack self-healing properties of HPC were studied. The hydration process and microstructure characteristics were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The crack self-healing capacity was evaluated by Brazilian test. The test results indicate that the SP has especially supplementary effect on water reducing and excellent property of better control of slump loss. The concrete flowability increases remarkably with the increase of SP replacement level in the range of 20% to 50%. The compressive and splitting tensile strengths of HPC containing SP are higher than the corresponding strength of the control concrete at all ages. The crack self-healing ability is highly dependent on SP content of HPC.

Key words: Superfine slag powder, High performance, Self-healing