Corrosion Performance Of The Steel Bars With Different Plastic Stress Under Different Chloride Environment

Currently, in the coastal region and in the region needs deicing salt melting inwinter, the durability problem of reinforced concrete structures under chloridecorrosion conditions, has received extensive attention of scholars. The corrosion ofsteel bars under chloride corrosion conditions exists as a main factor leading tostructures’ failure. In reinforced concrete structures, as the stirrups provide muchcontribution to component of shear capacity, it is essential to study the degradationof stirrups’ mechanical properties. Preliminary research shows that the combinationof plastic strain and corrosion causes additional damages. But study of this aspect isnot completed. The specimens were not enough, and they were subjected to a plasticstrain of just4%which was such low. In view of above situation, this paper studiesaround the corrosion effect on different degree of the plastic strain of stirrups. Inorder to accelerate the experimental process and reasonably simulate actualengineering, this paper also explores the steel corrosion accelerating test method. Thecontent includes:(1)Analyze the effect of stirrups corrosion on the shear capacity of thereinforced concrete beams. Based on stirrups’ special formation, calculate stirrups’different degree of the plastic strain in the bent corner.(2)From some aspects, such as inducing rebar corrosion mechanism, corrosionproducts, surface morphology and degradation of stirrups’ mechanical properties,summarize the distinctions of the accelerating corrosion method. On this basis, putforward to a test method named―High pressure-Dry-Wet cycle‖, which may bettersimulate actual corrosion of steel bars in the reinforced concrete structures.(3)Experiment explored that the "High pressure-Dry-Wet cycle" test method isfeasible. From some aspects, such as the surface features of the concrete specimenswith corrosion steel bars and corrosion steel bars, surface morphology of cleanedcorrosion steel bars and degradation of stirrups’ mechanical properties, suggest thatcompared with "Electroosmosis-constant Current-Wet and Dry cycle" and artificialclimate environment test method, the test method put forward to in this paper maybetter simulate actual corrosion of steel bars in the reinforced concrete structures.(4)From such aspects, as surface morphology of cleaned corrosion steel barsand degradation of stirrups’ mechanical properties, analyze the differences andsimilarities of steel bars,which had similar corrosion rate and different degree of theplastic strain under different test methods. The imposition of the plastic strain and thecorrosion process resulted in a significant alteration in the performance of steel bars.The increase of the degree of the plastic strain of the steel bar had as a result asignificant decrease in the ductility properties of the steel bars, despite the parallel increase in their stress.