Effect Of Seawater Corrosion On Bonding Properties Of Modified Carbon Nanotube-PVA Hybrid Fiber Reinforced Concrete And Steel Bar

At present,there is a problem of insufficient durability in reinforced concrete engineering,and the engineering problems caused by insufficient durability are becoming more and more serious.With the aging of buildings and the increase of environmental pollution,the corrosion of reinforced concrete structures has become a serious problem worldwide.The premise of the bond between steel bars and concrete is to have sufficient cohesive force.In recently years,many scholars have found that by adding fibers in concrete,not only the steel bars and concrete are not easily corroded,but also the bond strength between them can be enhanced.The contents of this paper mainly include the following parts:(1)By studying the effect of single fiber blending into hybrid fiber on the mechanical properties of concrete,mainly include: cubic compressive strength,axial compressive strength,flexural strength.The research shows that the compressive strength of concrete can be reduced by a single polyvinyl alcohol(PVA)by a certain amount,however,the enhancement effect of carbon nanotubes(CNT)is more obvious.When carbon nanotubes(CNT)and polyvinyl alcohol(PVA)are mixed,the compressive strength has been enhanced in general.In terms of flexural properties,the concrete after fiber addition is generally superior to ordinary concrete.Among them,the hybrid fiber has the best flexural resistance,and the toughness change of concrete is obvious.(2)By simulating corrosion in seawater in various types of concrete,and electrochemically accelerated corrosion of steel bars,then the steel bar drawing test was carried out to study the effects of different corrosion rates on the adhesive properties of reinforced concrete.The study shows that the addition of fiber improves corrosion resistance,hybrid fiber has better corrosion resistance and can minimize the value of bond strength.(3)Through the experimental and theoretical analysis,based on experimental bond slip curve,from initial slip to the broken end to extract the eigenvalues corresponding to the according to the bond slip curve.Applying the characteristic model,the constitutive relation of the bond slip of concrete and corroded steel bars is derived.(4)By applying ABAQUS to simulate the bond strength between steel and concrete under different corrosion rates,and the nonlinear spring element is used to simulate the bond relationship between corroded steel bar and concrete.Thencompare with the experimental results and the simulated finite element,the error rate of experiment and simulation is within a reasonable range.