Current Practice Sheet No. 132 Measuring the corrosion rate of reinforced concrete using linear polarisation resistance

摘要

Reinforcement corrosion is one of the main causes of reinforced concrete deterioration. Corrosion cannot be visually detected until cracking or rust stains appear at the concrete surface. Timing of repair and renovation are dictated by economics and safety considerations. Information on corrosion rates can give early warning of durability problems to help owners to select appropriate remediation options. Measuring the polarisation resistance of reinforcing steel is one of the few methods of assessing corrosion rate. It is a useful indicator for future maintenance strategies rather than just giving information about present corrosion activity. Instrumentation typically costs over ￡5000, and measurements are quite time-consuming at around 5╚D10 minutes. Although well-tried and tested in the laboratory, Linear Polarisation Resistance (LPR) is not as frequently used in the field as half-cell potential and concrete resistivity techniques.