Chloride Ion Penetration In Concrete Under Fatigue Loadings

Reinforced concrete structure can reasonable use of steel and concrete characteristics of the two materials,and be good,integral sex is good,good durability and fire resistance as well as the advantages of easy to use local materials,is widely used in the areas of civil and transportation in our country.However,a large number of engineering cases show that with the passage of time,the mechanical properties and durability of the reinforced concrete structure gradually degraded,lead to length of service can not meet the target,the main reason is due to the reinforced by corrosion,gradually in the process of service and the chloride ion is the main factor that leads to reinforcement corrosion.The chloride ion erosion is an important factor of influence of reinforced concrete durability,load level important effect on porosity and crack of concrete structure,reduce the ability of concrete resistance to chloride ion erosion,accelerated the failure of concrete.Fatigue load is one of the most common load in practical engineering,the chloride ion penetration under the static load at the present stage of research is common,and the study of chloride ion penetration under fatigue load is less,especially for the coupling of fatigue under the action of chloride ion penetration.The article studies the compression fatigue under coupling action of erosion of chlorine ion in concrete,test stress level and fatigue number two factors,the design of three groups of different stress level and fatigue,in this paper,the work and the research content is as follows:(1)Chlorine salt making cube concrete specimen,through artificial simulated environment and fatigue effect,inspects the chlorine salt environment and fatigue load under the dual influence of the durability of concrete performance,the study of chloride ions in concrete under fatigue load the infiltration law;(2)To compare different stress level and different number of fatigue under coupling action of chloride ion in concrete permeability,explore stress level and the correlation between number of fatigue and chloride ion permeability;(3)Based on the cube specimens,the ultrasonic wave velocity,analysis of CT number after fatigue load of concrete damage degree,explore the fatigue damage mechanism of concrete under the action of damage degree and the correlation of chloride ion permeability.(4)Considering the concrete damage degree and stress accelerated factor,and based on the existing model and the Fick's second law,find a damage parameter and chloride ion diffusion coefficient of correlation function;(5)Summaring the full text of the research content and the conclusion,and puts forward the shortcomings of existing studies and problems that need further study.