Research On Effects Of Freezing And Thawing Cycles And Temperature Changes On RC Beam Reinforced By CFRP Plate

Carbon fiber reinforced composite materials(Carbor Fiber Reinforced Polymer,CFRP)are widely applied in the bridge reinforcement in recent years.CFRP plate has advantages of strong corrosion resistance,good tensile performance,good fatigue performance,and small density.However,the design of CFRP plate reinforced bridge consideres its long-term performance and the influence of environmental factors inadequately at present.Therefore,it is important to research on the different environmental factors on CFRP reinforced concrete girder bridge effect.In this research,the main research contents are as follows:(1)Through the indoor experimental studies,the effect of CFRP plates and prestressed CFRP plates reinforcing RC beam on their bending bearing capacity.The results show that the utilization of CFRP plates can improve the flexural bearing capacity of T beams.After pre-stressing could eliminate stress hysteresis phenomenon in CFRP plates,which could further enhance the flexural bearing capacities of the reinforced structures.When CFRP plates were damaged,reinforcement of the bearing capacity of the T beams dropped significantly.(2)Through freeze-thaw cycles test and indoor loading tests,the effects of freezing and thawing cycle on CFRP plates and prestressed CFRP plates are analyzed.Freeze-thaw cycles main influenced the extents of inelastic deformation.With the increasement of external load,the effects of freeze-thaw cycles were more obvious.With the increasement of prestress levels,the more significant influence of the freeze-thaw cycle was observed.Affected by freezing and thawing cycles,the damage forms of prestressed CFRP strengthening RC beam was changed to with the interface stripping.Freeze-thaw cycles under the action of CFRP plate reinforced RC beam effect will be significantly reduced.(3)Instance bridge prestressed CFRP plate reinforcement,for example analysis of temperature change on the prestressed CFRP plate,and the effects of strengthening RC beams are studied.Actual measurement results show that the temperature variation of strain of CFRP plate cannot be ignored.The long-term effect of temperature and strain can be consumed points of shear strength of the bonding layer,adhesive layer of creep will cause the loss of prestress,bring T beams with prestressed CFRP plate negative effect.