海洋环境混凝土对流区形成机理及氯离子迁移速率分析

Analysis of chloride ion migration rate and formation mechanism of convection zone in marine concrete

混凝土在青岛实海暴露3、9、13个月,研究其在干湿交替区(浪溅区、潮汐区)和水下区的表层氯离子浓度分布,确定氯离子在干湿交替区的对流区深度及迁移速率。结果表明,干湿交替区腐蚀13个月混凝土表层氯离子浓度存在一个局部峰值,该峰值位于3~5 mm深处。水下区腐蚀混凝土长期处于饱和状态,不存在对流区海水溶蚀及硫酸根离子作用导致混凝土氯离子结合能力随腐蚀龄期增加而下降,并导致其表层自由氯离子迁移速率高于内部离子迁移速度3倍左右。

The concrete was exposed for 3,9,13 months respectively in Qingdao,the chloride ion concentration distributions of marine concrete are studied in the surface of the dry-wet alternate zone（splash zone,tidal zone）and the submerge zone respectively,which determines the depth and migration rate of chloride ion in the dry-wet alternate convection zone.According to the results,there is a local peak in the surface chloride ion content of concrete eroded for 13 months in the dry and wet alternate zone,the peak locates 3~5 mm deep.The corroded concrete in submerge zone is in a saturated state for a long time,there is no a kind of phenomenon that the effect of sea water corrosion combined with sulfate ion in convection zone leads that with the increase of corrosion age,concrete chloride ion binding ability declines,and leads that the migration rate of free chloride ion in the surface is about three times that of inside.