摘要
参照地铁工程结构服役环境,研究混凝土中钢筋在杂散电流、氯离子及其耦合等3种不同腐蚀环境下的腐蚀演变规律,杂散电流用直流电模拟。研究结果表明:杂散电流单独作用下混凝土中钢筋的锈蚀可分为加速腐蚀和平稳发展2个阶段,而氯离子单独作用下混凝土中钢筋的锈蚀则是一种缓慢而平稳发展的过程,且杂散电流引起钢筋的腐蚀速率较氯离子引起的钢筋腐蚀速率大。杂散电流和氯离子耦合作用下,由于杂散电流能使氯离子加速向混凝土内迁移,钢筋腐蚀速率明显增大,缩短混凝土中钢筋由钝化状态到混凝土保护层开裂的时间。地铁工程结构服役环境中钢筋腐蚀与杂散电流强度、氯离子浓度及腐蚀时间有关。杂散电流强度和氯离子浓度越大、腐蚀时间越长,混凝土中钢筋腐蚀越严重。
In view of the service environments of subway engineering structures,experiments on corrosion of reinforced concrete （RC） in three different corrosion environments of stray currents,chloride ions and their combination were carried out respectively and the corrosion developing laws were investigated.Stray currents were simulated by direct currents.The results show as follows：Under the sole action of stray currents,corrosion of rebars in concrete undergoes two stages,i.e.,the accelerating stage and the steady developing stage,whereas under the sole action of chloride ions,corrosion of rebars in concrete is developed slowly and steadily,and the rebar corrosion rate due to stray currents is greater than that due to chloride ions; under the coupled action of stray currents and chloride ions,since stray currents speed up transportation of chloride ions into concrete,the corrosion rate of steel in RC is increased and the time from passivating of steel to cracking of concrete cover is shortened obviously; in the service environments of subway engineering structures,the steel corrosion degree of RC depends on the stray current strength,the chloride ion concentration and the corrosion duration; the greater the stray current strength,the heavier the chloride ion concentration and the longer the corrosion duration,the more serious the corrosion of steel in RC.
出处
《铁道学报》
EI
CAS
CSCD
北大核心
2013年第9期112-117,共6页
Journal of the China Railway Society
基金
国家重点基础研究发展计划(973计划)(2011CB612210
2009CB623200)
国家自然科学基金(50968006
51002050)
关键词
钢筋混凝土
杂散电流
氯离子
电化学试验
腐蚀速率
reinforced concrete
stray current
chloride ion
electrochemical test
corrosion rate
