盐渍土环境下钢筋混凝土腐蚀劣化行为及竞争失效分析  

Analysis of Corrosion-induced Deterioration Behavior and Competing Failure of Reinforced Concrete in Saline Soil Environment

作　　者：孟祥晖 冯琼[1] 张云升 乔宏霞[1] 谢晓扬[1] MENG Xianghui;FENG Qiong;ZHANG Yunsheng;QIAO Hongxia;XIE Xiaoyang(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;School of Materials Science and Engineering,Southeast University,Nanjing 211189,China)

机构地区：[1]兰州理工大学土木工程学院,兰州730050 [2]东南大学材料科学与工程学院,南京211189

出　　处：《材料导报》2023年第14期40-49,共10页Materials Reports

基　　金：国家自然科学基金(52008196,U21A20150,52178216)。

摘　　要：针对西部盐渍土地区钢筋混凝土结构病害严重问题,本工作以格尔木重盐渍土地区土样作为电解质代替传统盐溶液模拟盐渍土地区实际腐蚀环境,进行通电加速腐蚀试验;通过电化学参数、损伤度、质量损失率及腐蚀开裂形貌观测,评价盐渍土环境钢筋混凝土的腐蚀劣化行为;选取钢筋混凝土性能劣化有效评价指标,基于Weibull分布参数估计建立钢筋混凝土在盐渍土环境下的劣化模型,进行竞争失效分析。结果表明:随着通电时间的延长,钢筋混凝土内部钢筋腐蚀倾向逐渐增大,从钝化状态转变为腐蚀活化状态,并逐渐达到高等腐蚀速率状态;腐蚀电流密度和混凝土损伤度可作为钢筋混凝土性能劣化的有效评价指标,且其随时间的变化规律均符合Weibull分布函数;在盐渍土环境,钢筋腐蚀破坏为钢筋混凝土结构前期劣化的主导因素,而混凝土损伤则为钢筋混凝土后期劣化的主导因素。Aiming at the serious problem of structural damage of reinforced concrete in the areas with saline soil in the west,we uses soil samples from the areas with severely saline soil in Golmud as electrolytes instead of traditional salt solutions to simulate the actual corrosive environment in saline soil areas and conducts accelerated corrosion tests by employing electrical current.The corrosion-induced deterioration behavior of reinforced concrete in saline soil environment was evaluated by electrochemical parameters,degree of damage,rate of mass loss and corrosion cracking morphology observation.The effective evaluation index of performance deterioration of reinforced concrete was selected,and the dete-rioration model of reinforced concrete in saline soil environment was established based on Weibull distribution parameter estimation for competing failure analysis.The results show that:with the time increase of employing electric current,the corrosion tendency of the internal reinforcement in reinforced concrete gradually increases,and changes from the passivation state to the corrosion activation state,and gradually reaches the higher corrosion rate state.The current density for corrosion and the degree of concrete damage can be used as effective evaluation indexes for the deterioration of reinforced concrete performance,and their variation patterns over time are in accordance with the Weibull distribution function.In saline soil environment,corrosion damage to the reinforcement is the dominant factor in the pre-deterioration of reinforced concrete structures,while concrete damage is the dominant factor in the post-deterioration of reinforced concrete.

关 键 词：钢筋混凝土 盐渍土 腐蚀劣化 WEIBULL分布 竞争失效 

分 类 号：TU528[建筑科学—建筑技术科学]