混凝土中不同等级钢筋锈蚀行为的比较

Comparative Study on Corrosion Behavior of Steel Bars of Different Grades in Concrete

为比较受氯离子侵蚀的混凝土中HPB235级、HRB335级和HRB400级钢筋以及钢绞线的锈蚀速率和锈蚀特征,设计了同时含有上述4种钢筋的混凝土试件,在4个多月的人工气候环境加速锈蚀试验过程中,利用电化学测试系统测试钢筋的锈蚀速率,并在锈蚀过程结束后剥离混凝土,对钢筋的锈蚀特征进行分析.结果表明,变形钢筋(包括HRB335级和HRB400级)的锈蚀速率明显比光圆钢筋(HPB235级)和钢绞线快,而HRB335级和HRB400级钢筋的锈蚀速率相近,后者略大于前者;HPB235级钢筋的表面锈蚀特征相对均匀,而HRB335,HRB400级钢筋和钢绞线表现出明显的局部锈蚀特征.最后,从钢筋的化学成分、微观结构及制作工艺等角度进行了机理分析.

In order to compare corrosion rate and corrosion characteristics of steel bars, such as HPB235, HRBB35, HRB400 steel bars and steel strands in concrete under chloride attack, three concrete specimens reinforced with the above four types of steel bars were tested. The specimens were corroded under artificial climate environment for four months. The corrosion rates of the steel bars were measured using CS300 Electrochemistry Workstation, and the corrosion characteristics of the steel bar surface were studied. It is shown that the corrosion rates of the deformed bars（such as bars HRB335 and HRB400） are higher than that of the plain bars（HPB235） and the steel strands,and the corrosion rates of bars HRB335 and HRB400 steel bars are close. However, the latter corrodes with slightly high rate than the former. The surface corrosion characteristics of HRB335, HRB400-grade steel bars and steel strands show obviously pit corrosion characteristics, and HPB235-grade steel bar shows relatively uniform. Finally, the mechanism of corrosion are analyzed based on the electro-chemical and metallographic principles.