| A unique patented field system for measuring the rate of corrosion and other parameters of reinforcement bars.
Corrosion Rate
A true measure of the corrosion rate is possible using the polarization
resistance technique. It has been well established in the laboratory by
Stern and Geary that corrosion current is linearly related to polarization
resistance.
Over a period of four years Gecor 6™ was developed by several research organizations. The polarization resistance is measured with a central reference electrode, surrounded by an external counter electrode. A unique guard ring and external electrode system confines the area of the rebar tested. This makes the Gecor 6™ the only field method for determining polarization resistance that is verifiable with proven laboratory techniques.
Gecor 6™ gives the corrosion rate (Icorr) which is a quantitative
measurement of the amount of steel turning into oxide at the time of
measurement. The current can be converted into metal section loss by
Faraday’s Equation.
Corrosion rate values measured by Gecor 6™ give precise information on the risk of corrosion and the following broad criteria have been established:
Icorr <0.2µA/cm2 Passive condition
Icorr 0.2 to 0.5µA/cm2 Low corrosion
Icorr 0.5 to 1.0µA/cm2 Moderate corrosion
Icorr >1µA/cm2 High corrosion rate
Corrosion rate measurements with Gecor 6™ should be taken at strategic locations. Other data such as chloride concentration, carbonation depths or half cell potentials and resistivity that can also be measured with Gecor 6™, should be considered.
Corrosion rates vary during the life of the structure, depending on the variations in concrete moisture content, chloride concentration and temperature. Measurements at different intervals should be carri |
