Research On Environmental Zonation Of Concrete Structures Durability In Wuhan Iron And Steel Industrial Estates

As the work environment of industrial buildings varies greatly due to the differentproduction process requirement, failure types and reasons of concrete structuresdurability in industrial buildings, which have the characteristic of regions, aregenerally complex compared with civil constructions. Therefore, it is necessary toensure the influence of concrete structures durability in the variety of environmentalowing to different production process and the determination to design requirements ofconcrete structures durability on different levels of environmental zonation. Theresearch on environmental zonation of concrete structures durability could mitigate theadverse impact of environmental effects on concrete structures and provide the safety,durability and economy of industrial buildings in concrete structures under industrialenvironment in general.The main reason influencing the concrete structures durability is reinforcementcorrosion due to acid gas erosion under steel industry environment. In the backgroundof Wuhan Iron and Steel Industrial Estates (WISIE), the production processes inWISIE were investigated and environmental parameters of the main productionprocess in WISIE were analysed. WISIE is made up of four process areas, which arethe coking area, the smelting area, the steelmaking area and the rolling area,respectively. The durability status of concrete structures in each process area wasinitially investigated.Focus on the ammonium sulphate workshop in the coking plant and the secondsteelmaking plant in WISIE, the environmental parameters including ambienttemperature, relative humidity and corrosive gas (i.e. CO2, SO2) concentration, were on-site monitored. The apparent damage of structures, concrete strength, concretecover thickness and concrete carbonation depth were on-site detected. The surveyresults indicate that the durability status of concrete structures in WISIE is severe. Theconcrete surface generally appears the phenomenon of peeling and flaking off. Thecarbonation depth of partial bent frame columns is larger and steel corrosion is moreserious.Based on different types of durability damage and environmental parameters themain production process in WISIE, BP neural network method and the life predictionmethod based on reliability (Monte Carlo method) have been used to complete theenvironmental zonation of concrete structures durability in WISIE under SO2gaserosion and concrete carbonation, respectively. In comparison with the damage degreeof concrete structures under both type of durability damage, the environmentalzonation of concrete structures durability in WISIE is finally determined. Consideringthe level of importance with concrete structure members, the suggested design valuesof concrete structures durability in WISIE with different zonation levels have beengiven.