Experimental Study On Bond Performance Theory Between GFRP Bar And Concrete

Fiber reinforced composite plastic(fiber reinforced polymer FRP)with its light weight,high strength,high corrosion resistance,fatigue resistance,provides the ideal method to solve the problem of reinforcement corrosion.The bonding performance between FRP tendons and concrete is the key to FRP tendons and concrete can work together.Based on the 59 drawing specimens,including standard drawing specimen21,new type whole drawing specimen 14,intelligent GFRP tendons drawing specimen 24,making into a 150mm×150mm×150mm drawing of concrete specimen,the axial drawing experiment was carried out.Further study of GFRP bond performance between reinforcement and concrete.Experimental results show that GFRP rebar and concrete pull out drawing rib destruction form mainly includes the shear damage,concrete crushing destruction and concrete interface fracturing 3 kinds.Axis of standard drawing specimen bond slip curve can be divided into micro slip,slide,pull out phase,decline phase and residual phase fluctuations and the whole process of bond slip failure,an overwhelming proportion between reinforcement and concrete mechanical bite.The new axis of integral type drawing specimen bond slip curve can be divided into micro slip,slip,micro drop and residual stress fluctuation,micro rise paragraphs.Axis of standard drawing specimen is bigger than the ultimate bond stress axis of new drawing specimen.With the increase of GFRP rebar diameter,bond strength decreased.The longer the bond length,bond stress distribution is uneven,and the smaller the average bond stress,increased with the increase of the bond length and diameter.Two test ultimate bond stress is more and more close.Overall improve concrete strength of GFRP rebar and concrete bond stress effect is not obvious.Axis of contrast standard drawing specimens showed good sensitivity.The analysis found that the stress of the axis of the new drawing specimen,conforms to the actual stress state of GFRP rebar.Combining with two kinds of test,this paper puts forward a new GFRP rebar and concrete bond-slip constitutive relation,and the fitting values coincide with the test results is good,provided a certain reference value for structure design.Through the analysis of the intelligent GFRP reinforcement of the patch test results,has been found that the load early loading,the loading end relatively close and strain values of location was obviously higher than that of a location far from the strain value,and decreased along the bond length.GFRP rebar and concrete bond stress value will appear near the loading end maximum first,and the direction of progressive decrease from the loading end to free end;The bond between GFRP rebar and concrete will damage near the loading end first,falling damage of bond stress,bond stress peak in order to move towards the free end,the bond stress along the bond stress distribution,the length to keep from bond stress peak.Through this research and analysis,it provided some lessons for FRP bars and concrete bond slip test study and laid the foundation for in-depth,comprehensive and systematic study of the mechanical properties of FRP bars.