Experimental Study On Mechanical Properties Of Glass Fiber Modified Recycled Concrete

Recycled concrete is a kind of environmentally friendly concrete which can reduce environmental pollution,save resources and economize by using recycled aggregate to replace natural aggregate partly or completely.Due to the high porosity of recycled concrete,its compressive and thermal properties are poor.However,the addition of glass fiber increases the toughness of recycled concrete,plays a role in crack suppression,and improves the strength of recycled concrete.The effect is remarkable in its flexural strength,splitting tensile strength and fatigue resistance.Therefore,the application of glass fiber and recycled aggregate in concrete will have a broader development space.Based on C30 concrete,recycled concrete is prepared by replacing natural aggregate with 30% recycled coarse aggregate.On this basis,glass fiber recycled concrete with volume fraction of 0%,0.1%,0.3%,0.5% and 0.7% was prepared.Through compression test,splitting tensile test and flexural test of glass fiber recycled concrete and fatigue test of glass fiber recycled concrete under three stress levels,the effects of different glass fiber content on mechanical properties of glass fiber recycled concrete,as well as fatigue life,fatigue probability distribution and damage evolution law of glass fiber recycled concrete were studied.The main research work is as follows:(1)Through cubic compressive test and splitting tensile test,the influence of glass fiber volume ratio on compressive and splitting tensile properties of glass fiber recycled concrete is compared,and the failure process and morphology of specimens in the test are observed.(2)Through the bending test of trabecula,the effect of glass fiber with different volume fraction on the bending and bending properties of recycled glass fiber concrete was studied,and the peak load was obtained to prepare for fatigue test,and the failure process and shape of trabecula were observed.(3)Fatigue tests of trabeculae under three stress levels are carried out to obtain the fatigue life of glass fiber recycled concrete and draw the strain-fatigue curve.The fatigue life of glass fiber reinforced recycled concrete is analyzed by Weibull distribution data,the double logarithmic fatigue equation is deduced,the fatigue ultimate strength is obtained,and the fatigue damage mechanism is analyzed.