(1. Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources,Yangtze River Scientific
Research Institute,Wuhan,Hubei 430010,China;2. Guangzhou Baiyun International Airport Co.,Ltd.,Guangzhou,
Guangdong 510406,China)
Abstract:In order to study the corrosion damage of anchorage structure,the indoor accelerated corrosion tests and the mechanical tests of corroded specimens were carried out considering the effects of oxygen concentration and local corrosion. The electrochemical measurement and the local strain monitoring of reinforced material were conducted during the corrosion tests. The relationships between the pre-stresses,the environment pH values,the oxygen concentrations,the corrosion current density,the appearance damage characteristic,the corroded weight per unit length and the mechanical properties of anchor bars were analyzed based on the test results. The local strain development of the pre-stressed anchor under the different oxygen environment was also studied. The results show that the stronger the acidity is,the higher the corrosion rate in the weak acid environment. The oxygen has significant effect on the corrosion of the pre-stressed anchor and the corrosion rate increases whit the oxygen concentration increasing. However,the effects are insignificant when the concentration of oxygen exceeds a certain value. The corrosion weight per unit length increases as the oxygen supplying rate rises under the experimental conditions. The ultimate elongation,ultimate tensile load and elastic modulus decrease significantly with rising of oxygen concentration. At the same oxygen-supplying rate,the reduction rates of the ultimate elongation,the elastic modulus and the ultimate tensile load are highest,lower and lowest. The local corrosion leads the deviation of the force acting on the corroded section. The tensile strain shows an increasing trend at the oxygen-rich side and is changed to the compressive strain at the anoxic side.
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