The Research On The Durability Of Paste CFRP Reinforced Concrete Beams Under The Condition Of Loads In A Hot And Humid Environment

At present,China has reached more than 770,000 highway bridges seat,which rated as three bridges and more than accounted for 32.6%,the number of required bridge maintenance and reinforcement of more than 120,000,a large,increasingly onerous task of reinforcing the bridge.A large number of domestic and foreign small and medium-span concrete bridge reinforcement is often used to paste carbon fiber reinforced composite materials(Carbon Fiber Reinforced Polymer,abbreviated CFRP)reinforcement method,according to 693 after the operator has been reinforced bridge the statistical results,including the use of paste CFRP reinforcement bridge accounted for 53% of the total.Today,concrete girder bridge wide application of CFRP reinforcement and structural reinforcement,however,reinforced concrete or prestressed reinforced concrete structure after the addition baseload withstand external loads,but also may be exposed to a variety of harsh environments(such as: hot and humid environment,chemical environment,wet and dry cycles,marine environment,freeze-thaw cycles),structural reinforcement after the due performance degradation(decrease in durability,prestressed loss,damage and other interface)and the problem can not be properly used.Paste CFRP reinforced to ensure durability and reliability are major issues to ensure bridge safety and proper use.In this paper 12 pasted CFRP under loading / humid environment effects on reinforced concrete beam experimental study durability test parameters considered hot and humid environment(temperature 60 ℃,humidity 95%),degradation time(5 days,10 days,15 days 30 days,60 days)and sustained load level(0kN,24kN).Through experimental and theoretical research conclusions drawn following aspects:In this paper,the CFRP 10 under hot and humid environment / loads on reinforced concrete beam experimental study durability test parameters considered hot and humid environment(temperature 60 ℃,humidity 95%),degradation time(5 days,10 days,15 days 30 days)and sustained load level(0kN,24kN).Through experimental and theoretical research conclusions drawn following aspects:(1)With the increase in hot and humid environment of the release time of the destruction of concrete interface layer gradually transferred to the interface between the concrete and glue.(2)The ability to hot and humid environment on the bond between FRP and concrete have weakened the role of the force transmission effect is affected,load factors exacerbated the weakening effect.(3)Hot and humid environment acts on the ultimate bearing capacity of reinforced beams obvious adverse effects,and the longer,the greater the impact.Load factors exacerbated the negative impact that the ultimate bearing capacity decline further.(4)Load and coupling in hot and humid environment to some extent reduce the paste CFRP Reinforced concrete beams ductility,making the destruction of the beam is more brittle.