既有混凝土码头的氯离子侵蚀状况与钢筋初锈时间预测

Chloride ingress into existing concrete dock and corrosion initiation time prediction

分别对暴露时间为35、62、80个月的海港码头进行现场检测。基于检测结果,对影响混凝土耐久性的各参数的随机特性进行了统计分析,并对被检测混凝土结构的钢筋初锈时间进行了预测。结果表明,混凝土保护层厚度和表面氯离子浓度关系服从正态分布;氯离子扩散系数和临界氯离子浓度关系服从对数正态分布。扩散衰减系数服从正态分布,均值为0.37,变异系数为0.09。被检测码头结构的钢筋初锈时间约为80.2年。为了准确预测混凝土结构的钢筋初锈时间,应考虑氯离子扩散系数的时变衰减特性。

Concrete powder collected from three concrete docks,which have been exposure to chloride environment for 35,62 and 80 months,respectively,was tested.Based on the test result,the probability distribution of random parameters that affect the durability of rein-forced conrete structures is analyzed.And the corrosion initiation time of the given structure is also predicted.It is revealed that concrete cover depth,and surface chloride concentration follow normal distribution,while chloride diffusion coefficient and critical chloride con-centration obeys lognormal distribution.Diffusion decay index is best described by normal distribution,with mean value of 0.37 and coeffi-cient of variation of 0.09.The corrosion initiation time of given concrete dock is about 80.2 years.For a more accurate corrosion initiation time assessment,the time-dependent prosperity of chloride diffusion coefficient should take into account.