复杂环境下钢筋锈蚀特征对混凝土强度影响

Corrosion characteristics of rebar and its effects on concrete strength under multi-factors condition

采用外加直流电场和内掺氯化钠的方法模拟杂散电流和氯离子共存的腐蚀环境,研究了杂散电流与氯离子共存环境下钢筋锈蚀特征及其对混凝土强度的影响.结果表明:二者共存时对混凝土耐久性的危害远大于杂散电流单独作用;当二者共存时,钢筋锈蚀程度明显增加,钢筋由钝化状态到严重腐蚀状态时间大幅度缩短,且受腐蚀钢筋的电化学当量和腐蚀电流密度随着电流强度增大、氯离子浓度升高以及腐蚀时间延长而增大;同时,该条件下混凝土力学性能受损较为严重,其下降程度与钢筋锈蚀程度有关.

Corrosion characteristics of rebar and its influence on concrete strength were investigated under stray current and chloride ion coexisted condition. Loading direct current electric field and inner-introduced sodium chloride were used to simulate the condition of stray current and chloride ion coexistence. The results indicate that the hazard brought by the coexistence of stray current and chloride ion to the concrete durability is much more serious than that brought by the stray current alone. When stray current and chloride ion coexiste, the degree of rebar corrosion increases, and the chan- ging time between passivating and serious corrosion state is shortened substantially. The values of electrochemical equivalent and corrosion current density increase with the augment of the electrical field strength, the elevation of the chloride ion concentration, and the extension of the corrosion time. Meanwhile, the mechanical property damage of concrete is more serious in such condition, and the damage degree is related with the degree of rebar corrosion.