MECHANICAL-BEHAVIOR AND INTERFACIAL PERFORMANCE OF STEEL FIBER REINFORCED SILICA FUME HIGH-STRENGTH CONCRETE

In this paper, the flexural, split tensile, impact and fatigue performance of steel fiber reinforced silica fume high-strength concrete (SIFUMHSC) under static and dynamic loads are studied. The effect of the amount of silica fume on its performance, the strengthening effects of silica fume particle and steel fiber and their composite effect are discussed. Test results indicate to a full extent that different amounts of silica fume substituting for cement can remarkably improve the static and dynamic mechanical behaviour of steel fiber reinforced SIFUMHSC with other conditions unchanged and that the main reason for the change is that the addition of silica fume brings about a double interfacial strengthening effect of fiber-cement matrix and aggregate-cement matrix, thus improving the structure and characteristics of the interface. When the addition of silica fume is adequate, the H(v)-d, I(a)-d and CHAS-d curves tend to be horizontal, with differences disappearing between the interfacial layer and matrix, so that the size and number of crack sources in the interfacial zone and the whole matrix become smaller and less, and strengthening effects are better developed. This is the key to the desired performance of steel fiber reinforced SIFUMHSC.