氯离子在火灾后混凝土中的扩散模型

Diffusion Mechanics of Chloride Ions in Concrete after Fire

研究了火灾后混凝土结构中的氯离子分布及其随时间的扩散机理,建立了相应的数学模型,并采用现有的有关资料对模型的合理性进行验证,分析了该模型参数的灵敏度,从而为火灾后混凝土结构的耐久性评估提供了理论依据.

PVC (polyvinyl chloride) material products are widely used in all kinds of buildings. When fire happens, PVC material burns easily, and a great deal of HCl(g) is released. HCl(g) turns into acid mist with the presence of water vapor, and coagulate in the surface of concrete. At the same time, it will be quickly absorbed by concrete. When the concentration of chloride ions in the surface layer of the concrete is high, the chloride ions in the cover layer of concrete diffuse in-to inside of concrete with increasing time, which influences durability of concrete greatly. A mathematical model to describe the activity of chloride ions in the concrete after fire is set, the model is verified to be valid by the related data, and the sensitivity of corresponding coefficients is analysed. A theoretic basis for assessment of the durability of concrete structure after fire is proposed.