Influence of Mineral Powder and Fiber on Work and Mechanical Properties of Reactive Powder Concrete

To study the basic characteristics of silica fume and iron tailings modified concrete, silica fume and iron tailings powder were used to replace cement and river sand at a ratio of 0% to 20%. The optimal replacement ratio of silica fume and iron tailings powder was obtained through mechanical and chloride ion erosion tests; then, on this basis, steel fiber, basalt fiber and sisal fiber were added in a volume ratio of 0~2% to improve the mechanical properties of concrete. The results showed that: the compressive strength and tensile strength of concrete increase first and then decrease with the increase of silica fume and iron tailing powder. The optimal replacement ratios of silica fume and iron tailing powder are 15% and 10%, respectively. Three kinds of fibers can effectively increase the compressive strength and tensile strength of concrete, but reduce the slump of concrete. The addition of 5% silica fume and 10% iron tailings powder can improve the corrosion resistance of concrete, but too much iron tailings powder is detrimental to the corrosion resistance of concrete; basalt fiber is better than steel fiber and sisal fiber in improving the chloride ion resistance of concrete; SEM analysis also obtained the same conclusion.