Experimental Research、predict And Analysis On Fatigue Performance Of Hybrid Fiber Reinforced Concrete

In the field of civil engineering, a growing number of concrete structures suffer to fatigue loading. Such as the joint of city’s elevated rail bridge, concrete crane beams, high-speed roads, airport pavements, offshore platforms. With the structural strength enhanced and weight decreases, the proportion of cycle dynamic loads such as wind loads, wave loads increase, which decided that concrete fatigue can not be neglected.Besides its low-cost, Hybrid fiber reinforced concrete can play all the advantages of different fibers, Based on puting HFRC in use in military protection engineering, this paper did the research of HFRC’s(Steel-Polypropylene Hybrid the Fiber Reinforced Concrete) bending fatigue properties.The important contents of which are summarized as follows:1.On the basis of the system test, bending properties of plain concrete (Concrete), Polypropylene fiber reinforced concrete (PFRC), steel fiber reinforced concrete (SFRC), And hybrid fiber reinforced concrete (HFRC) are studied. The results show that the steel-polypropylene fiber reinforced concrete can effectively improve the flexural tensile strength of concrete, and has a good toughening effect.2.Bending fatigue test are done by using four kinds of materials including C, PFRC, SFRC and HFRC, through the test,we get the fatigue life of materials in different stress levels and the strain-fatigue life curve.We use Weibull distribution theory and Logarithmic normal distribution theory to simulate the fatigue life.By comparating the results we found that the Weibull distribution theory is much more applicable to analysis the bending fatigue life of Steel-Polypropylene Hybrid the Fiber Reinforced Concrete.3.By theoretical analysis, we get the logarithm fatigue equation under different probability of failure,By studing the law of four kinds of concrete flexural fatigue damage, We get the damage of hybrid fiber to concrete material anti-fatigue.4. Based on the concrete fatigue test results of different stress levels, gray GM (1,1) model are set up to predict the fatigue strength of hybrid fiber reinforced concrete, the results show that the method is accurate enough.5. Respectively from energy conservation point of view and the crack propagation mechanism to explain some phenomena in the test, more in-depth understanding of hybrid fiber reinforced concrete fatigue process.