CORROSION PERFORMANCE OF WEATHERING STEEL IN HIGHWAY BRIDGES.

At several sites throughout Great Britain long term exposure trials have been carried out under both open and sheltered conditions with Cor-Ten B weathering steel and a special mild steel containing copper. These tests showed that open exposure corrosion tests were not generally applicable to steel sheltered by a bridge deck. Both the form and level of the corrosion-time curves, as well as the color and texture of the rust, could differ considerably in these two exposure conditions. Cor-Ten B corroded at a generally lower rate than the special mild steel, but severe pitting was apparent on Cor-Ten B specimens from sheltered marine environments. It is recommended that bridges constructed in weathering steel should incorporate some form of corrosion monitoring such as test specimens for periodic removal.