Experimental Study On Mechanics Performance Of The Rusted Steel Fibers And The Corroded Steel Fiber Reinforced Concrete

Steel fiber reinforced concrete (SFRC) is a new kind of composite material formulated by the setting and hardening according to a certain proportion of short steel fibers, cement, sand, stone and water, as well as the necessary admixtures new composite material.SFRC has better mechanical properties than ordinary concrete, steel fiber improve and enhance the performance of concrete, it is a innovation in the traditional concrete materials field. Nowadays construction safety and durability have become increasingly demanding,because of SFRC has a variety of superior performance, SFRC has be used widely at home and abroad.Commonly steel fiber used in actual project has a small diameter, once steel fiber was rusted, it can severely influence its enhanced affect, thus affecting the performance of steel fiber reinforced concrete structure. At present, scholars at home and abroad do a lot research on durability of concrete, but mostly research are limited to the study of ordinary concrete and steel corrosion, study on steel fiber corrosion resistance and corrosion of steel fiber on the mechanical properties of concrete is few. Therefore, the study on corrosion of SFRC basic mechanical properties has important theoretical and practical significance.In this thesis, mainly focused on the corrosion mechanism of SFRC and reinforcement mechanism were analyzed and summarized, respectively, studied the corrosion rate of the steel fiber in chloride environment, the mechanical properties before and after the corrosion and corrosion of SFRC basic mechanical properties. The main contents and results are as follows:(1) Determined by geometrical and physical properties of the three kinds of steel fiber shear, milling, cutting-the three kinds of steel fiber various performance indicators. The results show that the three kinds of steel fiber length, the equivalent diameter, aspect radio, bending performance, all able to meet the requirements of concrete steel fiber (YB/T151-1999)(2) Research on corrosion of the shear steel fiber, milled steel fiber, cut-off steel fiber in chloride solution, study the corrosion rate of the three kinds steel fibers in chloride solution before and after the state of corrosion, corrosion basic mechanical properties. The results show that:three kinds steel fiber corrosion rapid in chloride solution as the immersion time increases occur, the flexural strength of steel fiber tensile properties lower quickly, among cut-off steel fiber has the best corrosion resistance, and shear steel fiber has the worst corrosion resistance.(3) By study on shear steel fiber, milled steel fiber, cut-off steel fiber pouring720100mm×100mm×100mm SFRC test block in the reference environment and under chlorine environment, after150days of wet and dry cyclic corrosion test, the comprehension performance of SFRC block different etching time, splitting tensile properties change. The results show that:concrete mixed with SFRC comprehensive strength, splitting tensile strength have improved to some extent, which is particularly evident in the improvement of the splitting tensile strength, while adding steel fibers in concrete after its the corrosion resistance is also greatly improved.