MECHANICAL BEHAVIOUR AND INTERFACIAL PERFORMANCE OF STEEL FIBER REINFORCED SILICA FUME HIGHSTRENGTH CONCRETE

In this paper, the flexural, split tensile, impact and fatigue performance of steel fiberreinforced silica fume high-strength concrete （SIFUMHSC） under static and dynamic loadsare studied. The effect of the amount of silica fume on its performance, the strengtheningeffects of silica fume particle artd steel fiber afld their composite effect are discussed. Testresults indicate to a full extent that different amounts of silica fume substituting for cementcan remarkably improve the static and dynamic mechanical behaviour of steel fiberr einforcedSIFUMHSC with other conditions unchanged and that the main reason for the change is thatthe addition of silica fume brings about a double interfacial strengthening effect of fiber-cement matrix and aggregate-cement matrix, thus improving the structure and characteristicsof the interface. When the addition of silica fume is adequate, the H-d, I-d and CHAS--dcurves tend to be horizontal, with differences disappearing between the interfacial layer andmatrix, so that the size and number of crack sources in the interfacial zone and the wholematrix become smaller and less, and strengthening effects are better deve1oped. This is thekey to the desired performance of steel fiber reinforced SIFUMHSC.