护环法在钢筋混凝土体系腐蚀评价中的可行性研究

Feasibility of guard ring method for corrosion evaluation in reinforced concrete

采用普通三电极体系评价现场大钢筋混凝土结构时,辅助电极面积与钢筋表面积相差很大而导致极化电力线难以均匀分布在钢筋表面,极化面积不确定。为解决这一问题,采用护环电极(Guard Ring Elec-trode,GRE or GE)方法即在普通三电极法基础上添加一圆环形护环电极(GE),通过GE电流将辅助电极(CE)电流限制在CE投影面积内,试验中评价了不同腐蚀状态的钢筋,并与均匀极化法对比,结果表明:在正确的电流限制下,护环电极法能够较准确地评价钢筋腐蚀状态,该方法尤其适合已脱钝体系。

When the three-electrode system was used to detect corrosion rate of on-site large reinforced concrete, it was prone to cause non-uniform current distribution on the rebars surface because of the large difference in size between Counter Electrode and Work Electrode（rebars）. So it was difficult to decide the real polarized surface area of rebars in reinforced concrete. In order to solve the problem, the Guard Ring Electrode Method was used to confine electric signal from CE in a constant area below CE. The experimental results of Guard Electrode Method（GEM） was compared with Uniform Polarization Method results, It indicates GEM can be used to evaluate preferably corrosion rate of reinforced concrete with excellent current confinement, especially active rebar in the concrete.