现役桥梁混凝土钢筋在自然环境下的锈蚀特征及分级评价

Concrete Reinforcement Corrosion Characteristics and Grading Evaluation under Natural Conditions

运用多种电化学方法,对现役桥梁进行了无损量化检测,分析了自然环境下的钢筋锈蚀特征,总结了自然环境对钢筋锈蚀率的影响规律,通过与前期实验室结果对比,揭示了自然环境与加速模拟环境的区别与联系.并对实测情况做了分级讨论.实桥测量结果表明：潮湿处的钢筋失重率最高达到33%,最低为18%;而干燥处钢筋失重率则分布在8%--15%之间.实测结果还表明：涂刷了防水层的箱梁及护栏,有助于保护混凝土内部配筋,能有效降低内部配筋的腐蚀速率,其失重率仅为4%~8%.承载重的桥台钢筋高于承载轻的护栏钢筋的锈蚀率.

The paper,by using various electrochemical methods,conducts non-destructive quantitative testing towards currently-used bridges,analyzes reinforcement corrosion characteristics under natural environment,concludes the influencing rule of natural environment on reinforcement corrosion,and reveals differences and correlations between natural environment and accelerated simulation environment by contrasting with preliminary laboratory results.It also has a grading discussion towards the actual measurement conditions.The real bridge measurement results show that：weight loss ratio of reinforcement under humid environment can reach a maximum of 33% and a minimum of 18%;while weight loss ratio of reinforcement under dry environment falls between 8%~15%.The actual measurement results also show that：box girder and guard bar coated with waterproof layer help to protect reinforcing bars inside the concrete and effectively reduce the corrosion rate inside reinforcing bars with weight loss ratio around 4%~8%.In addition,the corrosion rate of bridge abutment reinforcement with heavier load-bearing is higher than that of guard bar reinforcement with lighter load-bearing.It contrasts the precision of two testing methods and comes to a conclusion that testing precision of linear polarization method is higher than that of impulse current method.