Half-Cell Potential (HCP) is a nondestructive test method used to investigate the thermodynamic corrosion tendency of embedded reinforcing steel. Potential readings measure the electrical activity of the corrosion process. Corrosion occurs simultaneously at the anode and cathode areas of steel when iron ions are released (at the anode areas) into the concrete to react and form deposits (at the cathode areas).
The HCP method involves making one electrical connection between reinforcing steel and the positive terminal of a high impedance voltmeter, and another connection between the negative terminal of the voltmeter and a reference electrode (RE). The RE consists of a copper electrode, enclosed in a plastic housing and surrounded by a saturated copper sulfate solution. The end of the cell is a porous disk, through which the copper sulfate solution can make electrical contact with the concrete. The most widely used half-cell RE is the copper-copper sulfate (CSE) reference cell.
YAES professionals have vast laboratory and field experience investigating corrosion-related problems in concrete structures related to penetration of chlorides and/or carbonation of concrete. Carbonation occurs when CO2. from the atmosphere reacts with concrete. The HCP test method is performed following the test procedures recommended by ASTM C876, Standard Test Method for Corrosion Potentials.
The HCP test method is used to identify the probability of corrosion activity of steel reinforcement in reinforced concrete structures. YAES professionals have used the HCP test method extensively to investigate corrosion activity in reinforced concrete bridge decks, tunnel liners, plate-like structures such as walls and slabs, and structures such as beams and columns.