咸潮上溯对河口船闸混凝土结构氯离子浸透的影响

Effect of Saltwater Intrusion on Chloride Ion Permeation in Concrete Structure of Estuarine Lock

由于受咸潮上溯与船闸灌泄水共同影响,在河口船闸内部将形成混掺盐水高频干湿交替的特殊腐蚀环境。该腐蚀环境相较于海洋干湿交替区域的氯盐浓度虽低,但其内水位频繁变化所造成的高频率干湿交替特征显著。针对上述特殊腐蚀环境对船闸混凝土结构中氯离子浸透的影响程度目前尚不清楚。为此,本工作通过开展由于咸潮上溯引起的盐水高频干湿交替环境下船闸混凝土内氯离子浸透试验,研究了不同氯盐浓度、干湿制度、干湿交替频率、暴露时间对混凝土内氯离子浸透深度的影响。结果表明:氯离子浸透深度随着干燥时间的增加呈现先增大后减小的变化趋势;高频率干湿交替、低浓度氯盐环境情况下混凝土内氯离子浸透深度大于低频率干湿交替、高浓度氯盐环境,表明干湿交替频率是影响氯离子入侵混凝土的决定性因素,对混凝土中氯离子浸透的影响效果较环境中氯盐浓度要更大。

Due to theboth influences of saltwater intrusion and irrigation/drain in Lock chamber,a high-frequency drying and wetting alternating corrosive environment of mixed salt water will be formed inside the estuary ship lock.Compared with the marine drying-wetting area,although the concentration of chlorine salt in the aforementioned corrosive environment is lower,the high frequency drying and wetting alternating characteristics caused by the continual water level fluctuation in the environment is very significant.The influence degree of the chloride penetration in concrete structure of ship lock is unclear under the aforementioned special corrosion environment.Therefore,this paper carried out a chloride ion permeation test in concrete under the saline water high-frequency drying and wetting alternating environment to investigate the influence of various environmental chloride concentration,drying-wetting ratio,drying-wetting frequency and exposure time on chloride ion permeation depth in concrete.Results showed that the chloride penetration depth increases firstly and then decreases with the drying time increasing.The chloride penetration depth in concrete under the condition of high-frequency drying-wetting alternation and low environmental chloride salt concentrations is greater than that of low-frequency drying-wetting alternation and high environmental chloride salt concentrations,which indicates that the drying-wetting alternation frequency is the decisive factor affecting the chloride penetration into concrete of ship lock.The influence of drying-wetting frequency on chloride ions penetration in concrete is greater than that of the environmental chloride salt concentrations.