EXPERIMENTS IN GALVANIC CORROSION OF STEEL IN CONTACT WITH CFRP COMPOSITES IN MORTAR AND CONCRETE

摘要

Galvanic corrosion is a possible form of deterioration when CFRP and steel are in direct contact in concrete, as in stirrups tied to prestressing CFRP tendons. Laboratory experiments were performed to determine the magnitude of galvanic currents that may take place as a consequence. Preliminary results show little galvanic corrosion of steel (up to 0.01 μA/cm~2 of current density) when coupled with CFRP composite in chloride contaminated wet concrete (w/c=0.41), and in mortar free of chlorides. However, significant galvanic action (steel current densities as high as 1 μA/cm~2 ) was observed in chloride contaminated mortar with a higher water to cement ratio (w/c=0.5). The study suggests that steel corrosion caused by de-icing salts or marine exposure may be aggravated by the direct contact between steel and CFRP.