摘要
经现场调查及试验发现,混凝土中存在箍筋锈蚀较纵筋严重或交叉钢筋相交处锈蚀严重的现象。为了量化比较微观锈蚀与交叉钢筋间的宏观锈蚀,且不考虑力学损伤(如弯折)对钢筋锈蚀性能的影响,将配有交叉钢筋的混凝土试件置于海洋大气环境模拟箱中进行锈蚀试验。试验结果表明,交叉钢筋间的宏观电流密度i_g约占钢筋自腐蚀(微观)电流密度i_(corr1)的1/10～1/1,钢筋的微观锈蚀占主导地位。基于试验结果,采用蒙特卡洛法对交叉钢筋间宏观锈蚀作用下混凝土梁、板的时变抗力进行了算例分析。结果表明,与仅考虑箍筋微观锈蚀的情况相比,当i_g与i_(corr1)的比值接近于1时,微观与宏观锈蚀耦合作用下混凝土梁的失效模式会过早地由受弯破坏转变为受剪破坏;对混凝土板而言,i_g仅为i_(corr1)的1/10时,也会使混凝土板在长期锈蚀过程中的失效概率增大。
The corrosion of steel reinforcement is found to be more severe at stirrups or the intersection zones of steel rebar mesh in concrete.This paper presents the investigation of the raicrocell and macro-cell corrosion between crossed steel bars in concrete.Corrosion experiments of concrete specimens embedded with crossed steel were conducted under simulated marine atmospheric environment.The experimental results indicate that the ratio of macro-cell current density ig to the mieroeell current density icorr1 ranges from 1/10 to 1/1.Mierocell corrosion is the major mechanism in the corrosion of crossed steel bars in concrete.Based on the experimental results,analyses of the time-dependent capacities of reinforced concrete beams and slabs were carried out.The results show that when the value of ig/icorr1 approaches to 1,the failure mode of a beam can be much sooner transformed from flexural failure to shear failure than that without considering the macro-cell current.As for the flexural capacities of slabs,even when the value of ig is only 1/10 of icorr1,considering the ig can lead to a significant increase in the probability of failure for a slab in the long-term corrosion period.
作者
董征
顾祥林
张伟平
袁琴
DONG Zheng;GU Xianglin;ZHANG Weiping;YUAN Qin(Key Laboratory of Performance Evolution and Control for Engineering Structures of the Ministry of Education, Tongji University,Shanghai 200092,China;College of Civil Engineering,Tongji University,Shanghai 200092,China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2019年第1期105-112,共8页
Journal of Building Structures
基金
国家自然科学基金重大国际(地区)合作研究项目(51320105013)
国家重点基础研究发展计划(973计划)(2015CB655103)
关键词
钢筋混凝土构件
交叉钢筋
模拟海洋大气环境
宏观锈蚀
时变抗力
reinforced concrete structural member
crossed steel bar
simulated marine atmospheric environment
macro-cell corrosion
time-dependent capacity
