Bond Behavior Between PVA Fiber Reinforced Concrete And Steel Rebar Under The Influence Of Chloride

Polyvinyl alcohol(PVA)fiber is a kind of organic synthetic material,which has high hydrophilicity in concrete,strong bonding with cement matrix and effective restriction on cracking of concrete over long term.PVA fiber has been widely used in many applications in civil engineering.The slump of concrete decreases obviously with the increasement of PVA fibers,which will lead to the construction difficulty,concrete compactness drops and so on.In this case,the corrosion damage of rebar occurs easily under the corroded environment,which significantly affects the bond strength between steel and concrete.After that,the durability of concrete structures was affected directly.At present,there are relatively few studies on the effect of chloride erosion on the bond performance between rebar and PVA fiber reinforced concrete.Therefore,in this paper,the experimental test is proposed to study the bond behavior of PVA fiber concrete and rebar,the effects of PVA fibers on the corrosion damage and bond degradation of concrete and rebar under chloride environment.The detailed content is as follows:(1)The influence of single PVA fiber on the mechanical properties and chloride permeability resistance of concrete was investigated.Four batches of specimens with different PVA fiber content were poured,and the effects of fiber content on the compressive strength,splitting tensile strength,direct tensile strength and flexural strength of concrete were clarified.The resistance of PVA fiber concrete to chloride salt penetration was studied through chloride salt immersion test.The influence of PVA fiber on the meso-pore structure of concrete was revealed through scanning analysis of specimen section.(2)The bond behavior between PVA fiber concrete and rebar was studied.Twenty specimens were designed for pulling test to explore the influence of PVA fiber content,steel diameter and concrete protective layer thickness on the failure mode of specimens and the bond performance of reinforced concrete.The influences of different variables on the bond strength,the slip corresponding to the bond strength and the initial bond stress of specimens were investigated.(3)The rust-swelling characteristics of PVA fiber reinforced concrete and the bond degradation law between rebar and PVA fiber reinforced concrete under the influence of chloride salt were investigated.The rust swelling characteristics of PVA fiber reinforced concrete were investigated by the method of accelerating corrosion with electricity.The drawing failure patterns of corroded specimens were revealed,and the degradation law of bond performance between PVA fiber reinforced concrete and rebar under the influence of corrosion was defined,and the bond mechanism between PVA fiber reinforced concrete and corroded steel bar was revealed.