杂散电流与氯离子耦合作用下钢筋锈蚀

Study on Rebar Corrosion under Coupling Action of Stray Current and Chloride Ion

目的研究钢筋混凝土结构在杂散电流和氯离子耦合作用下钢筋锈蚀的演变规律,从而揭示钢筋的损伤机理,为此类结构的耐久性设计提供理论依据.方法试验共设计20组砂浆试件,采用电化学测试技术对杂散电流以及其与氯离子耦合作用下钢筋的锈蚀变化规律进行分析研究,试验采用直流电模拟杂散电流.结果两种腐蚀环境下钢筋的自腐蚀电位随着侵蚀时间、杂散电流强度以及氯离子质量浓度的增大而减小;杂散电流单独作用对钢筋锈蚀影响相对较轻,而在二者耦合作用下钢筋的锈蚀速率明显增大;另外,在耦合腐蚀环境下杂散电流强度对钢筋锈蚀速率的影响程度比氯离子含量影响要大.结论根据试验的测试结果,杂散电流与氯离子的耦合作用会加速钢筋的锈蚀,降低结构的服役寿命.

This paper studied the evolution law of rebar corrosion in reinforced concrete structures under coupling action of stray current and chloride ion in order to reveal the damage mechanism of reinforcement bar and provide a basis of durability design for structures. 20 groups of mortar speci- mens were prepared to examine the evolvement rule of corrosion under action of stray current and coupling action of stray current and chlorine ion using electrochemical measurement technology. The stray current was simulated with direct current. It shows that the self-corrosion potential of rebar in two corrosion environments decreases gradually with increase of corrosion duration, stray current strength and chlorine ion concentration; the effect of the stray current alone on rebar corrosion is relatively smaller;but the corrosion speed of rebar obviously increases under coupling of two corrosion environments. In addition, in coupling of corrosion environments, the effect of the stray current on the corrosion rate of rebar is more heavily than the effect of chlorine ion concentration. Conclusion is that the coupling attack of stray current and chloride ion can accelerate corrosion of rebar and reduce the structural service life.