The Analysis On The Flexural Fatigue Performance Of Glass Fiber Reinforced Concrete

At present, glass fiber reinforced concrete is widely used in road bridge engineering, hydraulic engineering, architectural decoration engineering and so on. However, it has been limited to local reinforce and it is rare in the application of single structure. In order to study the mechanics properties of glass fiber reinforced concrete adequately and expand its engineering entity applications, the fatigue property and damage degradation regular pattern have been researched by means of a good many tests in this paper.The static mechanical properties of GFRC have been studied by twenty-four pieces of standard cube specimen and twelve pieces of rectangular beam in the paper. The main results obtained from the tests shows with the increasing of glass fiber reinforced contents (0.6%,0.8%,1%) the compressive strength has decreased respectively8.4%,9%,26.2%, but the splitting tensile strength have raised respectively15%,27.9%,20.6%, and the flexural strength have raised respectively17.3%,13.6%.17.5%, the bending modulus is no change.Afterwards, the fatigue life with different kinds of glass fiber proportion and different stress levels can be obtained according to flexural fatigue tests of sixty-three pieces of rectangular beam. It is the S-N Curve, P-S-N Curve and flexural fatigue equation that we have obtained, the fatigue life can preferably obey two-parameter and three-parameter Weibull distribution, but the three-parameter Weibull distribution is so much the better. Based on Miner linear accumulative damage theory, we can get the P-D-s Curve, damage threshold stain and ultimate strain. In order to analyze the law of degradation of flexural rigidity, we define the damage variable through modulus of elasticity. It is shown that fatigue failure will happen when modulus of elasticity reduce to64%of initial modulus of elasticity. Meanwhile. by means of micro loss test to forecast fatigue life, we can get the conclusion that the forecast value and measured value are in two times discrete range. Based on the first law of thermodynamics, we have researched development direction of glass fiber reinforced concrete. It shows that the dissipation energy per unit volume will increase with recycle ratio increasing. present three development stages change rule, with fiber contents increases.