Research On Carbonation Rule Of Fly Ash Concrete Under Bending Loading And Enviroment

Under the common atmosphere environment, the durability of concrete structures in the actual engineering is extremely complex, and is a kind of degeneration process carbonation; corrosion or freezing-thawing cycles and so on under many kinds of destruction factor interact under load. The form and size of load that concrete structures endure inevitably affect the deteriorated velocity of concrete. Therefore, based on relatively mature durability research in single factor, establish durable damage mechanism consistent with the actual engineering structure; study the concrete structure durable question under the multiple damage factors. It has vital significance to the accurate forecast concrete structure life as well as the durable appraisal.In view of the purpose, based on fly ash concrete carbonation test as well as fly ash concrete carbonation test under bending load and environment, the paper studies the impacts of water-cement ratio (0.35, 0.45, and 0.55), fly ash proportion (0%, 15%, and 30%), pouring side, steel bar existence and bending stress level (0, 0.2, 0.4, and 0.6),to concrete carbonation depths. With the help of the influence coefficient K_s of steel bar existence and the interaction coefficient K of CO₂ two-dimensional proliferation, the carbornation situations of steel bar existence and the angular region concrete are studied. The test results indicate that steel bar existence can inhibit concrete carbonation to a certain extent, the influence coefficient of steel bar existence and carbonation age conforms to logarithm relation; CO₂ two-dimensional proliferation has obvious interaction; the greater fly ash content is, the greater the angular region concrete maximum carbonation depth is; the concrete carbonation depth under the bending tensile stress is bigger than the concrete carbonation depth under the unstressing condition, the concrete carbonation depth under the bending compressed stress is smaller than the concrete carbonation depth under the unstressing condition, the bending tensile stress level and the concrete carbonation depth conform to the linear relation.