Study On Influence Of The Mechanical Properties Of The Steel Bars After Rust With Two Kinds Of Corrosion Methods

Corrosion of reinforcing bars not only is an important reason causing the reduction of structural resistance for reinforced concrete, at the time also is the main factor affecting the durability of it. Based on the study of problems existing on the corrosion of reinforcing bars, further collection and summary of the former research findings,in addition, through design and fabrication the size of 400mm×300mm×100mm reinforced concrete specimen by own, carry out the simulation experiment of the reinforcing steel’s natural environment corroded and applied current accelerated corroded experimentation, thus obtained two type of corroded steel bars specimens. Then mainly carried out the following work:⑴ Corroded steel bar corrosion morphology on the surface of the form are discussed, on this basis of geometric parameters of the corrosion pit(depth H、length L、width W) are carried on the statistics and analysis, got them with quality corrosion rate hm with in 0%~15% change of the regularities distribution; Specifically speaking is the length and depth of corrosion pit with the increase of the corrosion degree all by asymmetrical skewed distribution to approximate normal distribution, along with the development of the degree of corrosion and the corrosion pit width keep obey approximately the normal distribution.⑵ To total of 96 root of two methods of corrosion to get corroded reinforced specimen carried out mechanical tensile test. based on the test results, comparison and discusses the two types of corroded reinforced the load-deformation curve changes with the increase of the degree of corrosion on the similarities and differences, Found that when the quality of corrosion rate is small(hm[3%), two types of corroded reinforced the load-deformation curve are close to not corroded reinforced; but with the increase of the degree of corrosion(5%￠hm[15%), the load-deformation curve will be obvious changes, in the same place for them is yield load, ultimate load and axial tensile deformation decreases with the increase of the corrosion rate of steel quality; the difference is close to levels of corrosion, simulating natural environment corrosion method of mechanical properties of the steel specimen than electrify accelerated corrosion method, the mechanical properties of corroded reinforced specimen degradation of faster.⑶ By using curve fitting method to get the two types of mechanical performance index(the nominal yield stress ?yc、the nominal ultimate stress ?uc、elongation after fracture δsc)of the corroded reinforced with the biggest cross-section corrosion rate between the degradation law; by comparative and analysis the obtained degradation law of formula, discusses the mechanical performance of steel rust after respectively in different corrosion method、steel shape the degradation rule of difference.⑷ Using the element analysis software ANSYS simulation analysis the corrosion pitted round steel bar the change of corrosion pit geometry parameters、distance between and position change to the difference of effects on the mechanical properties, found that the effect of pit bottom emergency centralized with corrosion pit depth development of the most significant increases, while there is little effect on mechanical property of corrosion pit width、length and distance between of pitting corrosion of steel; For deformed bars, pitting corrosion occurred in its different parts of the influence on its mechanical properties are different, specific for the base circle and longitudinal ribs pitting corrosion pit will be in the bottom of the obvious stress concentration effect cross rib is pit corroded without and the effect on the mechanical properties of deformed bars is not obvious.