Research On Metal Corrosion Based On Devices Of A Bow-shaped Specimen

Corrosion of reinforcement is the main reason for durability of concrete structure,and the correct test of corrosion of reinforcement is the most important basis for evaluating the service life and maintenance of concrete structure.This paper not only summarizes the reinforcement corrosion reasons,the monitoring method and rust corrosion rate characterization,now will be based on the identification of a new type of metal corrosion mechanics method,independent design and processing for nearly 500 groups of bow-shaped specimens,and use them to the characteristics of the metal from rust and corrosion rate law study,the main work and achievements are as follows1.The mathematical derivation of the mechanical identification principle of metal rust was perfected;A stress calibration table was developed according to the bow device,which improved the efficiency of the bow-shaped specimen and controlled the specimen's variation with in 1%;LDV technology is used to accurately determine the tension of the bow-shaped specimen,and the effect of stress relaxation is eliminated through the real-time monitoring data analysis,thus ensuring the feasibility of the bow-shaped specimen.2.Compared with electrochemical method and mechanical method,it is found that the two have positive correlation;Through statistical analysis of the measurement results of mechanical methods,the stability and effectiveness of the method are determined;Compared with the actual reinforced concrete structure,the mechanical method is highly efficient and sensitive.3.The influence of tension size,passivation time,chloride ion concentration and p H value on steel wire corrosion was discussed,the result show that:(1)The closer the tensile force is to the tensile strength limit of steel wire,the better the identification effect of the bow device.(2)In order to be objective and efficient,the corrosion rate can be calculated directly through the breaking time t_r.(3)Passivation time had a great impact on the steel wire corrosion,mainly caused by steel shows that the growth of passive film rule:passivation membrane along the radial growth first,then along the thickness of the growth,the passivation film on steel wire shows that coverage degree is directly related to the corrosion degree of steel wire;The above analysis can be confirmed by the microscopic appearance of passivation film on the surface of steel wire.(4)Cl~-and pH interaction in the process of steel corrosion,the Cl~-characterized by erosion,pH performance for"protection",as the coupling effect of deterioration,corrosion occurrence and evolution speed,until a certain degree of steel wire performance for general corrosion,has delayed the steel corrosion rate of evolution.(5)The critical chloride ion concentration of metal materials is not only related to Cl~-/OH~-,but also other factors,and the critical chloride ion concentration is also related to time.(6)The passivated metal material has a pitting corrosion under Cl~-action,and the number of pitting has an influence on the process of steel corrosion.