Bond Slip Constitutive Model Of Reinforced Steel And Rubber Modified Polypropylene Fiber Concrete

As an organic combination of new high-performance concrete and reinforcement,reinforced rubber-modified polypropylene fiber concrete can improve the ductility and seismic energy consumption capacity of the structure,and can effectively recycle and utilize waste rubber resources.In order to further study the bond performance of reinforced rubber-modified polypropylene fiber concrete,this paper uses model experiments and numerical simulation methods to study it.The main research contents and results are summarized as follows:(1)In order to develop better concrete composition suitable for reinforced rubber modified polypropylene fiber concrete,the mechanical properties of rubber modified polypropylene fiber concrete were changed.The silica fume was selected as the reinforcing material,and the rubber content,polypropylene fiber content and watercement ratio were taken as the influencing factors to carry out the drawing experiment in the center.The development of cracks on the surface of specimens measured in the experiment.The bond-slip curve,and the selection of specimens compared the strain distribution of steel rebar under different loads were also obtained.At the same time,a new specimen was designed in this experiment,and the "window" was carried out on the surface of the specimen,and DIC technology was used to carry out real-time monitoring of the strain distribution of steel rebar and the development of cracks in the whole field.(2)Under the action of central drawing load,the failure modes of reinforced rubber modified polypropylene fiber concrete structure can be divided into two types,namely split failure and split pull-out failure,in which the rubber content and polypropylene fiber content had certain influence on it.Compared with reinforced concrete structure,the reinforcement stress distribution in rubber-modified polypropylene fiber concrete was more uniform,which was due to its good energy dissipation capacity and ductility.The anchorage function of reinforcement in rubber-modified polypropylene fiber concrete was established.Through the above research,it was found that the ductility and energy dissipation properties of the specimen were significantly improved when the rubber content was 5% and the polypropylene fiber content was 1%.Moreover,the crack cracking can be effectively inhibited due to the polypropylene fiber content,so that the bearing capacity and plastic degeneration capacity were improved.(3)Based on experimental data fitting and experimental factors,a bond-slip constitutive model of reinforced rubber-modified polypropylene fiber concrete structure was established.In order to further apply it to practical engineering,it was also compared with the experimental data to verify its accuracy.