Research On Corrosion Fatigue Damage Degradation Of Subway Reinforced Concrete Structure Under Stray Current Corrosion And Its Service Life Prediction

Under the circumstances of global warming, the light rail and subway has graduallybecome the best public transportation tool because of their speed stability, saving a largenumber of time and the consumption of energy. However，suffered from coupling effect bystray current generated by the subway, the environment corrosion medium and locomotivefatigue load, the reinforced concrete structure has produced corrosion seriously in processof using, and has greatly affected the normal safety operation and servicelife of the concrete structure.The paper, which is a part of the Major State Basic Research Development Program ofChina (National973Project)project mechanism of chemical mechanicalcouplingdamage under the action of in multiple factors (Project Numbers:2009CB623203)， didtheoretical and experimental research on the fatigue damage degradation of reinforcedconcrete structure under different load level of the stray current corrosion and life prediction.The experimental and theoretical research includes three aspects of the fatigue damagedegradation laws of reinforced concrete structure under different load level of the straycurrent corrosion, the damage model and life prediction of reinforced concrete structure underdifferent load level of the stray current corrosion， and the electrochemical corrosionmechanism of reinforced concrete structure under different load level of the stray currentcorrosion. The main work and conclusions are briefly introduced as follows:1. Under the stray current and chlorine ion corrosion environment, did the corrosionfatigue experiment on reinforced concrete samples under different load levels, observed andanalyzed fatigue modulus damage evolution laws of the concrete samples, and the contrastshowed that the load level had effected on the damage degree effect law of concrete samples.2. Through the method of tracking test in the midspan displacement immediately, didresearch on the whole fatigue damage process of reinforced concrete samples under thecorrosion action of the stray current and chloride ion, and established four points bendingfatigue damage prediction mode of the corrosion environment based on in the midspandisplacement on the basis of the corresponding relationship with fatigue stiffness. That is theservice life prediction equation of subway reinforced concrete, and, with the help of thismodel, predicted and assessed the service life prediction equation of subway reinforced concrete under the corrosive environment and at the same time, contrasting and checking bythe experimental value and predicted value.3. Did experiment mainly on the corrosion of reinforced concrete samples, which beardifferent stress level of fatigue load under the stray current and chlorine ion corrosionenvironment, and tested the corrosion electrochemical parameters, including corrosion currentdensity, polarization resistance and corrosion rate of concrete samples under different loadlevels when electrochemical reinforced corrosion of steel occur. Through the experimentaldata analysis, contrasted and analysed the corresponding relation curve of different load levelsunder the corrosive environment between the steel bar corrosion electrochemical parametersand fatigue load，such as the corrosion current density, polarization resistance and corrosionrate. By analyzing the corrosion law of steel bars effected by fatigue load under different loadlevels, studied the influence of load level on corrosion, so as to reveal the mechanism damageof steel bar, and confirmed that the load level factors did influence on corrosion.