氯盐侵蚀钢筋表面的坑蚀特征及蚀坑演变规律  

The character and evolution of corrosion pits on steel reinforcing bar surfaces corroded by chloride

作　　者：王波[1] 袁迎曙[1] 陈瑞[1] 

机构地区：[1]中国矿业大学力学与建筑工程学院,江苏徐州221116

出　　处：《中国矿业大学学报》2011年第2期240-245,共6页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(50538070;50878207)

摘　　要：对氯盐侵蚀环境下普通硅酸盐混凝土内锈蚀HRB335级变形钢筋表面上的蚀坑的形状、数量和尺寸进行了详细的观测和研究.通过统计分析建立了不同形状蚀坑的概率分布模型.结合金属腐蚀学的知识对蚀坑的生长机理进行了分析,并得到了蚀坑生长演变的规律.结果表明:在锈蚀初期,22%的微观蚀坑在闭塞电池作用下发展为深椭球形蚀坑,但多数蚀坑的纵横向腐蚀速率大于径向,使得40%的蚀坑呈圆球形,35%的蚀坑呈长椭球形;随着锈蚀率的逐渐提高,径向腐蚀速率下降,纵向腐蚀速率逐渐增大,深椭球形逐渐演变为其他形状,圆球形蚀坑逐渐演变为长椭球形;当锈蚀率超过4%以后,蚀坑横向曲率逐渐为0,长椭球形蚀坑逐渐演变为凹槽形.The corrosion of the reinforcement（HRB335） in ordinary Portland cement type concrete in a chloride ion environment was studied.The appearance,number,and dimension of the corrosion pits on the metal surface were determined.A probability distribution for each shape was established.Metal corrosion theory was used to analyze the growth mechanism of the corrosion pits.Initially,22 percent of the micro-pits grow into deep ellipsoidal pits because of the action of occluded corrosion cells.However,40 percent become spherical pits and 35 percent long ellipsoidal pits because of the higher corrosion rate in the longitudinal and transverse directions compared to the radial direction.As corrosion progresses the radial corrosion rate falls but the longitudinal corrosion rate increases.Hence deep ellipsoidal pits evolve into other shapes and spherical pits evolve into log ellipsoids.At more than 4 percent corrosion the long ellipsoids have evolved into grooves as the transverse radius of curvature gradually becomes zero.

关 键 词：钢筋 混凝土 氯离子侵蚀 坑蚀 生长演变 

分 类 号：TU528[建筑科学—建筑技术科学]