The Chloride Ion Transport Mechanism Of Concrete Under Carbonation Coupled With Flexural-Tensile Load

Corrosion of reinforcement is one of the main factors that influence the durability of concrete.Chloride ion penetration is an important cause of reinforcement corrosion. Flexural-tensile load is the most common load form of concrete beams,concrete permeability under flexural-tensile load will have a big difference with non-stress concrete. In coastal areas and northern deicing salt environment,carbonation, chloride ion penetration and loads have extremely important effects on concrete durability. At present, research on chloride ion transmission in concrete under multiple factors and their coupling effects is still at an early stage.Chloride ion transport problems are studied on this paper and concrete samples are under loads-carbonation and its coupling effect by a novel flexural loading device.Firstly, this paper studies physical properties and chemical compositions of the test materials, and confirms the test mix proportion of C30concrete.And it expounds the effects of carbonization time on the depth of carbonation and carbonization on concrete chloride ion permeability, as concrete specimens with different carbonation ages are obtained by rapid carbonization test, and they are tested with ASTM C1202method;and it analyses the micro-structure of concrete under carbonation or chloride ion penetration by SEM.Secondly, concrete specimens with different flexural-tensile load ratio are obtained by a custom mold and a novel flexural loading device. And they are tested with ASTM C1202method and carbonization test. It studies the effects on chloride ion penetration resistance and carbonization resistance of concrete under load,and it analyses the micro-structure of concrete under load by SEM.Finally, concrete specimens are made with different flexural-tensile load ratio, then they are tested by rapid carbonization. And electric quantity Q through the concrete specimens are measured with ASTM C1202method.It reveals the chloride ion penetration law of concrete under carbonation coupled with load,and it preliminarily analyses the micro-structure of concrete under carbonation coupled with load by SEM.