Half Cell Potential Measurement

• Principle
• Application
• Advantages
• Limitations
• Test Procedures

Test Procedures

Rebar locator, profometer & covermeter consist of electromagnetic cover devices used for determining the position and direction of reinforcement bars. These instruments give precise measurements of the concrete cover and estimation of the rebar diameter.

• Locate the reinforcement bars on the area to be tested using a covermeter.
• Mark the grid of the testing positions, as far as possible coinciding with the steel bars located.
• Remove the concrete cover to expose a small portion of the reinforcement bar.

• Make a direct electrical connection from the Half-Cell to the exposed reinforcement bar using the wire and clamp supplied.
• To ensure a low electrical resistance connection, scrape the exposed bar or brush the wire before connecting the bar.
• Wet the sponge of the half-cell by dipping into water and place the instrument together with the sponge on the testing positions (i.e. marked concrete surfaces) to obtain the electro-potential readings.
• Plot locations of half-cell potential values of the steel on the concrete and draw contours of equal potential.
• The probable risk of reinforcement corrosion can be evaluated in relation to potential readings. The reinforcement potential assessment criteria have been suggested is as shown in the following table.