Experimental Study On Fatigue Residual Strength Of Concrete Under The Condition Of Corrosion

Corrosion fatigue is that the structural components are imposed aftercirculating load of a kind of special degradation process in corrosive environment.In this process, the cyclic stress accelerated corrosion function, corrosionintensifies the component material fatigue damage. Because the influence of thecorrosive environment and complex load, we know the corrosion fatigue in theoccurrence and development process is certain difficulties. In the concrete materialinside the damage is the concrete structure is the main cause of fatigue damage.The project utilized test way, using a certain number of fatigue specimen todetermine the static load strength as the basis, draw P-R-N curve（In the equation,P for failure probability, R for residual strength, N times for fatigue），reveal theresidual strength of concrete fatigue decay laws; P-R-N curve can show theresidual strength of the attenuation and presents the corresponding assurance,Definition of several damage variables, Specimens of that damage law; Theboundary surface concept and continuum damage mechanics theory and have setup the corrosion condition concrete fatigue residual strength attenuation model（Concrete is seen as the damage the anisotropic material）.This projectcomprehensive consideration of the corrosion and fatigue of the influence of thestructure, through the residual strength reveals fatigue damage rule, to roads,Bridges and engineering construction and use of coastal structure has an importantpractical significance. To sum up, this paper mainly experiment and theoretical research work includes the following aspects:(1) Observe the damage form of concrete test blocks in four solution of thecorrosion process;(2) According to the test results the draw of the P-R-N curve（In the equation, P forfailure probability, R for residual strength, N times for fatigue）, and presents thecorresponding assurance；(3) In this paper, two kinds of residual strength of the definition of the damagevariables, through the test results in this paper, the model is proved effective；(4) The concrete compressive modulus is along with the cuts the increase ofnumber of fatigue and attenuation，Surplus cuts modulus and residual strengthbetween the square root of the linear relationship；The test results show：Sodium chloride solution to test blocks most seriouscorrosion，in turn, ammonium nitrate and sodium nitrate magnesium, And insodium chloride and nitric acid magnesium corrosion under the action of testblocks can be observed obviously slag off phenomenon; Through the residualstrength attenuation curve can see, the fatigue of the concrete compressive residualstrength in fatigue loading initial attenuation smaller, the attenuation at a slowerspeed. Destruction is near, the strength of concrete suddenly falls, the apparent"suddendeath", and the characteristic of the same conditions and time in the sodiumchloride solution of corrosion of concrete test is the most serious, the lowestbearing capacity, and ammonium nitrate solution of the corrosion of the concrete test "sudden death" characteristics of the most obvious; In the process of fatiguespecimens of the definition of the biggest strain injury variables, physical meaningclear, the measurement is convenient. Between damage variables and compressiveresidual strength have good linear relationship, However residual strength decaylaws and the damage development rules is very similar, it shows that the residualstrength of concrete is made of the attenuation damage; Through the aboveanalysis, learned that between cuts modulus of surplus compressive and the squareroot of the remaining compressive strength have a good linear relationship,and theresidual disusses the compressive modulus and fatigue with half a logarithmicrelationship between times.