Corrosion Protection for Hydraulic Steel Structures - A Survey of Actual Problems and an Outlook to the Future

摘要

Environment and labour protection actual is of main interest for corrosion works in general and particular in case of removing old coatings. Blasting of old coal tar containing coatings leads to a set-free of polycyclic hydrocarbons which are carcinogenic as well as asbestos fibres used as filling material. Present corrosion works therefore demand for new techniques of de-coating where a minimum of PAHs and fibres are emitted. The development of corrosion protection materials during the last decade is characterised by the reduction of non environment-compatible and toxic agents. Coatings became free of carcinogenic coal tar and subsequently were reduced in solvents. The results of numerous tests, in laboratory as well as in practice, have shown that the protection quality in general by that didn't suffer. As a consequence of the reduction of solvents the thickness of single layers of polymers could be raised up to 1000 urn. New test results of outdoor exposure tests as well as laboratory short tests confirm the decisive influence of the make-up of a corrosion protection system. Systems with primers, especially zinc-dust primers reduce rusting of substrate as well as blistering at the artificial scribe. Also the withstand to electric current, e.g. by cathodic corrosion protection, is meliorated by zinc dust primers. Nevertheless some systems without (zinc-filled) primer show also good performance.