连云港盐渍土中钢筋混凝土结构寿命预测

Life Prediction for Reinforced Concrete Structures Exposed to Saline Soil in Lianyungang

通过分析连云港盐渍土中盐分含量分布,指出连云港盐渍土属于氯盐渍土,盐分含量随土层深度的增加线性减小,对钢筋的腐蚀性为中等腐蚀性;综合考虑氯离子在混凝土孔隙溶液中的扩散、电迁移以及毛细吸附过程,建立氯离子运移模型;模型的计算结果与实测结果有较好的拟合度;采用有限元方法分析了连云港盐渍土环境下混凝土内部氯离子含量分布状况,并计算不同混凝土保护层厚度的结构物寿命,建议混凝土保护层厚度应该大于50 mm。

Through analyzing salt concentration profile of saline soil in Lianyungang,corrosion characteristics are presented.It is shown that saline soil in Lianyungang has a high concentration of chloride,causing a corrosion risk of middle degree to steel.Additionally,the salt content of saline soil decreases lineally with the increase of depth.Combining the transport mechanisms of chloride in pore solution of concrete,such as diffusion,migration and capillary suction,a model of chloride transport in concrete is given.The calculated results agree well with the test results in situation.Then,chloride concentration profiles in different years are calculated using finite element method.The service lives of reinforced concrete structures with different concrete cover thicknesses are also presented.It is suggested that the thickness of concrete protective cover must be larger than 50 mm.