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氯离子侵入引发钢筋腐蚀,降低了盐渍土环境下钢筋混凝土结构物使用寿命。综合考虑混凝土孔隙溶液中氯离子的扩散、电迁移以及毛细吸附等运移方式,建立盐渍土环境下氯离子侵入混凝土模型,预测结构物寿命。采用有限元方法分析扩散电场、毛细作用对氯离子运移过程的影响。分析表明,多种离子运移产生的电场加速了氯离子的运移过程,且毛细作用在早期会使氯离子在混凝土表层累积。采用氯离子侵入模型,分析了保护层厚度对结构使用寿命的影响,建议连云港盐渍土环境下混凝土保护层厚度应不小于50 mm。
Chloride ions invade lead to corrosion of steel, reducing the service life of reinforced concrete structures in saline soil environment. Considering chloride ion diffusion, electromigration and capillary adsorption in concrete pore solution, chloride ion intrusion concrete model in saline soil was established and life expectancy of structure was predicted. The influence of diffusion electric field and capillary action on chloride ion transport was analyzed by finite element method. The analysis shows that the electric field generated by many kinds of ion transport accelerates the migration of chloride ions, and the capillary action will accumulate chloride ions on the concrete surface in the early stage. The chloride ion intrusion model was used to analyze the influence of the protective layer thickness on the service life of the structure. It is suggested that the thickness of the concrete protective layer should be not less than 50 mm in Lianyungang saline soil.