Study On Long-term Mechanical Properties Of Concrete Axial Columns Under The Condition Of Steel Corrosion

Generally,reinforced concrete structures are subjected to external environmental erosion while they were subjected to loads.As a result,the mechanical properties of the materials and components of the reinforced concrete structure are degraded and the durability performance is affected.At present,in view of the long-term mechanical properties of reinforced concrete structures,there are few environmental considerations,and only the effects of changes in temperature and humidity are involved.Compared to corroded RC beams,the study of mechanical properties of corroded RC columns is relatively rare.Reinforced concrete columns are the main load-bearing components of reinforced concrete structures.The damage of reinforced concrete columns is more serious than that of other components.Therefore,it is necessary to carry out research on the long-term mechanical properties of concrete columns under the conditions of corrosion of steel bars,to understand their degradation laws and to reflect the actual stress states of the components,which has important engineering application values and theoretical significance.In view of the current research status of reinforced concrete columns,this paper mainly studies the long-term mechanical properties of concrete axial compression columns under corrosion conditions of steel bars.The specific research contents include:(1)Accelerated corrosion method in the room to perform different degrees of corrosion test on the concrete test block.The mechanical performance test of the concrete test block under the corrosion condition is performed,and the calculation model for the degradation of mechanical properties of concrete under the condition of corrosion is established,and the calculated results are not much different from the experimental results.(2)Loading device that works by specially designed corrosion and load,and use galvanostatic artificial accelerated corrosion method to rust steel bars in reinforced concrete columns.Reinforced concrete columns under corrosion of steel bars under long-term loading were studied.Mechanical properties,the degradation of the mechanical properties of reinforced concrete columns under corrosion of steel bars was discussed.(3)In this paper,based on the age-adjusted effective modulus method,the CEB-FIP90 model was revised,and the concrete shrinkage and creep prediction model was established considering the corrosion of the steel bar.There are some deviations between the theoretical calculation results and the actual measured values,but the difference is within the allowable range and can meet the actual engineering needs.Based on the balance of forces,a calculation model for the effective elastic modulus of concrete under consideration of corrosion of reinforcing steels was established,and the theoretical calculation results are in good agreement with the experimental measured values.The research results can be used for the durability design of reinforced concrete column structures,long-term stress performance evaluation and maintenance reinforcement,providing experimental basis and theoretical reference.