Research On Durability Environmental Index System For Concrete Structure Of Industrial Building

Concrete structures are widely used in industrial and civil buildings,but due to their insufficient durability,a large number of industrial building concrete structures fail before they reach the expected lifespan,which causes huge economic losses.Furthermore,the industrial environment inherits the characteristics include,but not limited to,high corrosive media diversity,high concentration,and strong corrosivity,which makes the durability of the concrete structure of industrial buildings more prominent.Therefore,the classification of environmental categories and action levels,combined with the establishment of a reasonable environmental index system are the key issues that need to be resolved in the durability assessment of industrial building concrete structures.There are many pieces of research on the durability index system of concrete structures in the general environment,however,there is still a lack of research on the durability environment index system of industrial building concrete structures.In this thesis,an on-site investigation and analysis combine with experimental simulation is adopted to study the durability environmental indicator system of concrete structures in industrial buildings.The contributions of this thesis can be summarized as follows:（1）Relevant data on the durability deterioration of concrete structures in industrial buildings is collected,and this thesis makes a detailed classification of the industrial building environment.To clarify the environmental factors and quantitative indicators that affect the durability of concrete structures in different industrial environments,this thesis investigates the durability of industrial buildings nationwide,and several representative projects are selected for detailed inspection.Besides,a thorough analysis of environmental data from nationally representative regions is implemented,which lays a solid foundation for establishing an environmental indicator system for the durability of concrete structures in industrial buildings.（2）An artificial climate environment test chamber is built to simulate the industrial environment and carry out concrete vulcanization corrosion tests,which is used to the appearance damage pattern of concrete vulcanization corrosion under different environmental conditions.A quantitative analysis of water-binder ratio,environmental temperature,environmental humidity,SO₂ concentration and other factors on corrosion depth is presented.And the environmental impact coefficients of these factors is thereupon introduced,after that,a calculation model of concrete sulfidation corrosion depth is established based on test data.（3）The main environmental influencing factors that affect the durability of concrete structures in industrial buildings is carried out to the established calculation model of concrete vulcanization corrosion depth.In this thesis,the KNN algorithm is adopted to classify the levels of environmental effects,and a concrete structure durability environmental index system is thereupon built.Based on the established durability environmental index system,several typical engineering examples are selected to classify the environmental grade,quantitatively compare the environmental factors of each process section with respect to the degree of durability and corrosion of the concrete structure.And the corresponding durability design recommendations are proposed to demonstrate the feasibility of the durability environmental index system.