Experimental Study On The Properties Of Steel Fiber Reinforced Concrete Beams Under Flexural Fatigue Loading

Steel fiber reinforced concrete（SFRC） has excellent tensile，flexural, impactand anti-fatigue properties, the performance of SFRC member make up of SFRC andreinforcing bar is popular attention, especially the fatigue performance has become ahot issue in the current. In this paper, SFRC beams with different fiber content weretested under static and fatigue loading，to study the affect of fiber content to theperforce of beams under static and fatigue loading, and combined with thecorresponding theoretical to explanation the law of fatigue damage of SFRC beams inthis experiment.By comparing the compressive strength of SFRC cubes with different fibercontent, to analysis the enhancement of steel fiber to concrete compressive strength.The results showed that: the enhancement of steel fiber to concrete compressivestrength is limited when the matrix strength is C35level. But steel fiber can increasethe ductility of concrete cube test block, and change its failure pattern.Flexural static loading tests were taken to SFRC beams with different fibercontent, to analysis the affect of steel fiber to the performance of SFRC beams underflexural static loading. The results showed that: steel fiber can improve ultimateflexural capacity of reinforced concrete(RC) beams evidently, can effectively inhibitthe expansion of cracks in concrete, can improve the overall stiffness of reinforcedconcrete beams, also had a significant effect in reducing the steel stress. The morefiber content the more obvious effects.Flexural fatigue test under different stress levels were taken to9SFRC beams.To analysis the affect of fiber content and stress level to the performance of SFRCbeams under flexural fatigue loading. The results showed that: the fatigue stress levelis higher, the fatigue life of beams is shorter, when beams have the same fiber content.The law of deflection and strain evolution of SFRC beams is presents three-stage withchanges in the number of fatigue.To establish the fatigue equation of SFRC beams with different fiber content.The fatigue life of SFRC beams are longer then RC beams when they are under thesame loading value, and the more fiber the fatigue life is longer. The stiffness attenuation is used for characterize the damage of beams, to establish fatigue damagemodel of SFRC beam. Finally, analysis the affect of steel fiber to the crackpropagation. The results showed that: the fatigue damage accumulation of SFRCbeam is slower, it has a better toughness. The fracture mechanics theory is used toexplain the law of concrete crack propagation.