Korrosion in Trennrissen nach Rissinjektion mit Polyurethan / Reinforcement Corrosion in Separation Cracks after Injection with PUR

Abstract

In separation cracks in RC elements (e. g. park decks), a short-term chloride exposure can already cause reinforcement corrosion. It is questionable, if a deep injection of the crack as an exclusive procedure is sufficient for effectively stopping the corrosion process. For investigating the corrosion activity during the chloride exposition and after the crack maintenance, cracked beams with crack-crossing reinforcement were fabricated. The cracks have been grout injected with PUR after a winter season of six month with a periodic chloride exposure. The anodic (element) current was recorded both before and after the injection. During chloride exposure the measured current flows were very high (sometimes > 200 μA). After the injection they slowly decreased and dropped nearly to zero in the next winter period. In the next summer the current flows increased just marginally, which seems to be mostly uncritical.