Mechanical Behaviour Of The Corrosion Damaged Stainless Steel Reinforced-concrete Members

In air,steam,water and salt solution,stainless steel is hard to rust.As the corrosion resistance of carbon reinforced concrete structure is bad,concrete structure in offshore and corrosive environment can use stainless steel to instead of the carbon steel to improve the durability.Unlike carbon rebar,stainless steel is a typical nonlinear material,and its constitutive relation curves has no obvious yield point and the yield platform.Generally,when the plastic strain is 0.2%,the stress is used as yield strength.In order to verify the stainless steel used in the engineering is feasibility,the stainless steel should be study in this paper.Experimental research and theoretical analysis are carried out:(1)Local pitting corrosion is a common corrosion form of steel bars and steel bars,and it is also the most obvious corrosion pattern of concrete structure.According to a large number of practical test data and durability degradation test data,Based on a large number of practical test data and durability degradation test data and assuming that the pit is a ellipsoid,3D finite element numerical simulation of local pitting corrosion was carried out.This paper discusses the influence of pit depth "d",pit width"b",pit length"l" on the mechanical properties of carbon rebar and stainless rebar,and analyzed the influence of pit shape parameter on coefficient of uneven stress.For the stainless rebar,the accelerated corrosion electrochemical test was carried out for the first time.Monitoring the corrosion current and impedance of stainless steel bars under different corrosion rates,the test result found that the corrosion current of the corroded steel bar is small,the impedance of the corroded steel bar is large.It is shown that the corrosion resistance of the no corroded stainless steel bars is strong.After the rebar begins to rust,corrosion current increased significantly and the impedance decreased significantly,and the ability to resist corrosion of steel bars become worse.(2)A test to know the bond performance of the stainless rebar and concrete with different corrosion rate was carried out,and the bond strength of 7 groups of specimens with different corrosion rates was obtained.The effect of corrosion on the bond performance should be summarized.The test results showed that the failure mode of stainless rebar specimen is mainly splitting failure.And the bond strength of the specimen is greatly weakened by the existence of the crack.The bond strength of stainless steel is same to carbon rebars,and the reinforcement type has no effect on the bond strength of the specimen(3)The flexural behavior test of stainless steel reinforced-concrete beams under different corrosion rate was carried out.The test results showed that the flexural capacity and ductility of stainless steel reinforced-concrete beams decrease with the increase of local corrosion rate near main crack.The distribution of rust expansion cracks on stainless steel reinforced-concrete beams is more uneven than that on the ordinary reinforced concrete beams,and the influence of corrosion on stainless steel reinforced concrete beam is more serious than that on ordinary reinforced concrete beam.