Testing Research On Freeze-Thaw And Carbonizationn Of Steel-Fiber Reinforced Concrete

Concrete structures are widely used in China. The consideration about durability of concrete structures has become very urgent at present. What we call the durability of concrete structure is that concrete structures have the ability of keeping their security, function and appearance requirement without costing much money to reinforce them under the influence of natural environment, application environment and internal factors of material. The experimental studies of the resisting freeze-thaw and carbonization capability of the steel fiber reinforced concrete have been done in this dissertation.In the freeze-thaw experiment , the grade of concrete intensity and the volume fraction of steel fiber are regarded as variable parameters and that 90 concrete specimens with the size of 100mmXI00mmXI00mm and 45 concrete specimens with the size is 100 mmX 100mm X400mm have been made. After the freeze-thaw circulations (50, 75 times), the basic mechanical property of the specimens has been tested. Based on the test data, it has been analyzed that the influence of the freeze-thaw circulation time, the grade of concrete intensity and the volume fraction of steel fiber on the basic mechanic property , such as compressive strength, splitting strength and flexural strength of steel fiber reinforced concrete, and on mass loss of this kind of material. The study result shows that steel fiber improved the frost-resisting property of concrete.In the carbonization experiment, the grade of concrete intensity, the volume fraction of steel fiber and carbonization time are taken as variable parameters. Through the carbonization experiment of 366 concrete specimens with the size of lOOmmX lOOmmX 100mm and 183 concrete specimens with the size of 100 mmX100mm X400mm, the basic mechanic properties before carbonization and after carbonization, such as compressive strength, splitting strength and flexural strength of concrete, of steel fiber reinforced concrete are measured, and also carbonization depth at every defined carbonization time. At the same time, the whole failure process and the failure mode of steel fiber reinforced concrete are surveyed. The reinforced mechanism of the steel fiber is studied, and theeffects of the volume fraction of steel fiber, the grade of concrete intensity, carbonization time on the basic mechanic property and carbonization depth are analyzed. At last, two experiment empirical formulas about carbonization depth have been put forward:...