冻融循环-氯盐侵蚀-荷载耦合作用下混凝土中钢筋的锈蚀行为  

Corrosion Behavior of Steel Bar Embedded in Concrete Subject to Freeze-Thaw Cycles-Chloride Attack-Flexural Load

作　　者：王阵地[1] 姚燕[1] 王玲[1] 

机构地区：[1]中国建筑材料科学研究总院,绿色建筑材料国家重点实验室,北京100024

出　　处：《硅酸盐学报》2011年第6期1022-1027,共6页Journal of The Chinese Ceramic Society

基　　金：国家“973”计划(2009CB623106)资助项目

摘　　要：为了研究路用混凝土中的钢筋在冻融循环-氯盐侵蚀-荷载多因素耦合作用下的锈蚀行为,利用开路电位法和动电位扫描法测定钢筋的自腐蚀电位、腐蚀电流密度和腐蚀速率。结果表明:与施加0.3应力比的相比较,施加0.4应力比的试件钢筋脱钝时间提前了50多个循环,高应力比缩短了钢筋脱钝的时间,增大了钢筋发生锈蚀的风险;极化曲线整体负移,阴极反应被抑制,在脱钝后钢筋的阳极溶解过程阻力变小,反应朝易于腐蚀的方向进行;腐蚀速率与腐蚀电流密切相关,100次冻融循环后,腐蚀电流密度和腐蚀速率分别表明钢筋将在10～15年内发生锈蚀,并在2年后,混凝土表面产生腐蚀裂纹。Corrosion behavior of steel bars embedded in pavement concrete subject to synergistic effect of freeze-thaw cycles,chlo-ride salt attack and external loading was studied.The corrosion behavior of steel bars was evaluated by measuring corrosion potential,corrosion current density and corrosion rate using open circuit potential and potentiodynamic polarization techniques.Results show that depassivation time of steel bar subject to a 0.4 stress ratio is more than 50 cycles earlier than that of the steel bar with a 0.3 stress ratio.High stress ratio shortens depassivation time of the steel bar and increases risk of steel corrosion.The cathodic reaction was inhibited with negative shift of polarization curve.Dissolution resistance of the steel bars decreases and the corrosion reaction takes place toward the direction of easy-to-corrode after the depassivation of the steel bar.Corrosion rate is closely related to corrosion current density icorr.After 100 freeze-thaw cycles,the results of icorr and corrosion rate show that the steel corrosion will occur in 10-15 years and the time from corrosion initiation to corrosion cracking is about 2 years.

关 键 词：多因素耦合 钢筋锈蚀 腐蚀速率 服役寿命 

分 类 号：TU528[建筑科学—建筑技术科学]