氯盐环境下混凝土中钢筋锈蚀性能试验  

Experiment on Anti-Corrosion Property of Steel in Chloride Concrete

作　　者：李志国[1,2] 刘成义[1] 林陈安攀 孙震洲[1] 

机构地区：[1]天津大学建筑工程学院,天津300072 [2]滨海土木工程结构与安全教育部重点实验室(天津大学),天津300072

出　　处：《天津大学学报（自然科学与工程技术版）》2015年第3期219-224,共6页Journal of Tianjin University：Science and Technology

基　　金：国家自然科学基金资助项目(61002027)

摘　　要：采用施加阳极电流的加速锈蚀方法,对分别单掺、复掺粉煤灰和Na NO2制成的4种钢筋混凝土小梁进行试验,测试暴露10,d后混凝土保护层的裂缝宽度和钢筋质量损失率,并利用Djxs-05钢筋锈蚀仪测锈蚀后各小梁的电位.结果表明,掺入粉煤灰或Na NO2对低碳冷拔钢筋、不锈钢钢筋起到一定的阻锈作用,但在高强调质钢筋混凝土中,粉煤灰并无明显阻锈效果,Na NO2则明显加速了其锈蚀速率;对于同种混凝土,含碳量越高的钢筋抗锈蚀能力越弱.分析认为,碳可作为钢筋锈蚀过程中原电池反应的电极,其含量越高,原电池反应越活跃,钢筋锈蚀速率越快.粉煤灰改善了混凝土的空隙结构,减缓了氯离子渗入混凝土中的速率,具有一定的阻锈效果.Na NO2一方面能提高钢筋开始锈蚀所需要的临界氯离子浓度,减缓钢筋开始锈蚀的时间,另一方面又作为导电离子增加钢筋中的电流密度,加速钢筋的锈蚀速率.在含碳量低的钢筋中,Na NO2的阻锈作用比较明显;在含碳量较高钢筋中,原电池反应活跃,NO2-加速锈蚀速率作用更大.The corrosion of steels in the single and compound doped concretre by fly ash and NaNO2 was tested in this paper and anodic current method was used to accelerate the corrosion speed of each steel. Four groups of concrete beam samples were tested after 10 days’ exposure. Results of cover width of cracks in concrete and weight loss of steel were gained,together with the corrosion potential in the concrete tested by Djxs-05. Results show that both fly ash and NaNO2 can increase the anti-corrosion performance of the cold drawn steel and stainless steel;while for the high strength indented bars,fly ash has little effect in anti-corrosion,NaNO2 even reduced the anti-corrosion perform-ance. For the same concrete bar,the anti-corrosion performance decreased with the increase of carbon content of steel. Analysis shows that cabon in the concrete could act as electrode in the chemical battery reaction in the steel cor-rosion,higher carbon content thus result in lower anti-corrosion performance. Fly ash in concrete can improve inter-face structure of the concrete bar,thus helps slow down the infiltration of chloride and increases anti-corrosion per-formance. Preservatives（NaNO2）can increase critical concentration of chloride for steel to start corrosion on one side,while its electroconductibility can accelerate the corrosion after the corrosion begins. In low carbon content steel,NaNO2 can reduce the corrosion speed of steel,while in high cabon content steel,NaNO2 can accelerate cor-rosion speed.

关 键 词：氯盐侵蚀环境 加速锈蚀方法 钢筋锈蚀 不锈钢钢筋 

分 类 号：TU502[建筑科学—建筑技术科学]