CORROSION OF WEATHER-RESISTANT STEELS SUBJECTED TO STRESS BY DEICING SALT ON ROADS

KORROSIONSVERHALTEN VON WETTERFESTEN STAEHLEN UNTER TAUSALZBEANSPRUCHUNG IM STRASSENBEREICH

AT PRESENT INSUFFICIENT INFORMATION EXISTS ON THE EFFECT OF CHLORIDE ON THE FORMATION OF THE CORROSION-INHIBITING SURFACE LAYER OF WEATHER-RESISTANT STEEL. PREVIOUS STUDIES OF THE EFFECT OF CHLORIDE IN THE AIR ON WEATHER-RESISTANT STEELS SHOWED THAT IN AREAS NEAR THE SEA THIS SURFACE LAYER DOES NOT FORM; HOWEVER IT IS NOT KNOWN WHETHER THIS IS DUE TO THE INCREASED CHLORIDE CONTENT OR TO THE LACK OF SULPHUR DIOXIDE IN THE AIR. AS REGARDS THE USE OF WEATHER-RESISTANT STEEL IN ROAD BRIDGES IT IS SIGNIFICANT THAT LARGE QUANTITIES OF DEICING SALT ARE USED ON ROADS DURING WINTER SERVICING, BUT THAT SUFFICIENT SULPHUR DIOXIDE IS GENERATED BY CAR EXHAUST FUMES. THE QUESTION OF THE FORMATION OF THE SURFACE LAYER UNDER THESE CONDITIONS IS TO BE EXAMINED BY MEANS OF 5-YEAR EXPOSURE TESTS ON SAMPLES OF DIFFERENT WEATHER-RESISTANT STEELS. THE EIGHT SITES ARE ON BRIDGES WITH ORTHOTROPIC SLABS AND ARE DISTRIBUTED OVER DIFFERENT CLIMATIC AREAS OF THE FEDERAL REPUBLIC OF GERMANY.