Experimental Study On Crack Resistance Behavior Of Hybrid Fiber Recycled Concrete Beams

With the development of rural urbanization and city construction,a large number of old buildings were demolished and rebuild,so it produced a lot of construction waste,and caused a serious burden in development of the city for a long time.In order to resource recycling and reduce environmental pollution.scholars at home and abroad have used fly ash and waste concrete into recycled concrete.Because of the use of these recycled concrete has lower strength and the crack resistance is poor,its practical use is limited.According to the research data show that:fiber can effectively make up the recycled concrete defects of porosity and low density.Therefore,in order to improve the cracking performance of recycled concrete beam,this paper changes the fiber with different kinds,different lengths and different methods of blending to analyze mechanical properties of the recycled concrete and the anti-cracking properties of the beams.The test results are as follows:(1)By experiment study on mechanical properties of fiber concrete with different kinds and lengths,the results show that:Mixing fiber to concrete impacts a little on compressive strength,but it can obviously improve the splitting tensile strength.By comparing ratios of tension and compression,this paper work out that anti-cracking ability of G12P35 is better.(2)By comparing anti-cracking performance experiment studies of different kinds of single fiber and hybrid fiber recycled concrete beams,the results show that:Breakdown process of recycled concrete beams with fiber are similar to the normal concrete beams,which all have four stages of elasticity,cracking,yield and limit.The addition of fiber does not increase the cracking load,however,the limit load of the component is improved to some extent.The results of the study were found by analyzing the load-fracture width,load-span deflection and crack number of different experiment group members,hybrid fiber is better than single fiber at improving the anti-cracking properties of recycled concrete beams.(3)According to the results of the experiment,this paper analyzes the maximum fracture width and deflection formula of code for design of concrete strutures,brings in influence coefficient K of maximum fracture width and influence coefficient N of maximum deflection,then calculates and deduces respectively.(4)Hybrid fiber recycled concrete beams were analyzed by using finite element software ANSYS,then comparing simulation values with empirical values,this paper finds out that simulated value matches the empirical ones well,which proves that finite element software ANSYS is applicable to the performance analysis of concrete components.