A New Identification Method For Corrosion Of Metallic Materials

Rebar corrosion caused by the chloride ion is usually considered as a main reason for the performance degradation of reinforced concrete structures by the coast,and the reinforcement corrosion is due to the concentration of chloride ion in its surface,reaching the threshold and damaging the passive film of the steel surface.The electrochemical method is a conventional method judging the rust and corrosion rate of steel bars,with an indirect test method and a test result with a great discreteness.Accordingly,based on a new device and principle for identifying the corrosion of steel bars and other metal materials,this paper discusses the technical problems and optional schemes with using the device for testing,providing the theoretical and technical support for series of further research on corrosion of metal materials such as steel bars and establishing a new identification criterion and test procedures.The main researches and achievements are as follows:1.This paper briefly introduces the the basic structure and principle of new type device identifying the corrosion of metal material such as reinforcements,it is made up of work pieces,mechanical wires and the connection part of the two items.The work pieces bend as a arch and apply different levels of predetermined stress to the wires,and the steel wires are used for simulating the bearing steel in an actual structure.According to the wire corrosion,the reinforcement corrosion and the corrosion rate can be identified.In view of the arch shape of the entire unit,the paper refers to it as the "arch type device".2.This paper discusses the technical feasibility for testing of identifying the corrosion of metal materials with the arch type device: stand the device in the vacuum environment for observation for a long time,rule out the fracture possibility of the arch wire due to the stress fatigue under the normal stress;observe the wire fracture with a microscopic under the corrosive environment,which proves that the wire fracture is caused by the corrosion damage.3.This paper establishes the important mechanical parameters of the arch type device with a push and some theory approaches--the straightforward wire stress calculation method,which mutually conformed the validity of the calculation results;then puts forward a method to make a target stress arch device and forms the corresponding patent draft,improving the efficiency and precision for series of research on stress corrosion by using of the arch type device.4.Considering the material characteristics,the packaged form of steel wires and connection part and other factors,this paper compares the effectiveness of the design schemes of the device,and picks up a design scheme with a stable test result minimal discreteness,which better solves the key technical problem for studying on steel corrosion and other metal materials by using the arch type device.5.This paper studies on the corrosion time of the steel wire and the variation pattern and the distribution characteristics of the corrosion rate with a reasonable test scheme providing by the arch type device,discusses the effect of stress level on steel corrosion and gets the preliminary results of scientific research for identification and influencing factors of metal corrosion.