ZBL-C310A rebar corrosion detector, rebar rust analyser, half cell meter
Single-electrode method applies testing principle of half-cell self-potential method, the rebar under ionic environment can be seen as an electrode, after corrosion, electrode potential change, therefore, potential reflects corrosion directly. As it is well-known, battery consists of cathode and anode. Since rebar electrode has only half feature of battery, therefore it is called half-cell.
Double-electrode method also applies self-potential method. The difference only lies in that single-electrode method applies to outside exposed structure of rebar end, while double-electrode method apllies to non-outside structure.
When tested with single-electrode method, a constant potential reference electrode(copper sulfate electrode or agcl electrode) should be placed on the surface of concrete to form battery with rebar, the we can identify the potential distribution throught testing the relative electric potential difference between rebar and reference electrode. Through summarizing statistical law between potential distribution and rebar corrosion, corrosion can be indentifed through potential test.
Double-eletrode method needs putting two electrodes which distance is constant on the surface of concrete. Moving these two reference electrodes on the surface of concretes, if the rebars under the two electrodes are in the same state, there is no potential difference; if different, such as one is in corrosion, the other is not, potential difference can be measured and corrsion can be identified successively.