Corrosion protection and assessment of weathering steel highway structures

Three studies, undertaken to investigate various issues related to the corrosion of weathering steel highway structures, are presented in this article. The first study examines the effects of corrosion products and pitting on weathering steel plate thickness measurements obtained using a standard ultrasonic gauge. The second evaluates the potential of several zinc-based coatings, including metallizing and zinc tape, as a way of protecting elements of existing corroded structures. The third study comprises a series of reliability analyses of composite weathering steel overpass structures with uniform corrosion occurring at various locations and rates. Based on this work, it is concluded that the examined coatings offer an effective way of improving the corrosion performance of weathering steel structures. From the reliability analysis study, it is concluded that corrosion can cause significant reductions in the service lives of weathering steel highway structures. The analysis results are seen to be most sensitive to the modelled corrosion conditions. Plate thickness measurements are seen to be vital for the assessment of weathering steel highway structures, due to the high uncertainty associated with the corrosion rate.