Analysis of Structural Compatibility at Interface between Asphalt Concrete Pavements and Orthotropic Steel Deck Surfaces

Abstract

Orthotropic steel deck is the most suitable solution for long-span bridges by virtue of its low weight and good mechanical properties. However, this deck shows a lack of adhesion with ordinary paving materials; for this reason special bonding coats are usually applied on the steel surface. Polymer-modified bitumen, asphalt-based mastic, epoxy asphalt, and reinforced asphalt membrane have been used at the interface between the hot-mix asphalt (HMA) course and steel bridge decks. A description of these materials and their construction process is provided. In some extreme situations mechanical reinforcement is necessary to provide adequate bonding between the steel deck and the asphalt pavement. The aim of this study was the laboratory evaluation of the shear properties of smooth and reinforced steel interfaces, which were coated with a polymer-modified bitumen and placed between the steel deck and conventional HMA. A suitable specimen preparation procedure was first defined. Shear resistance was evaluated with the ASTRA shear test device to investigate the effects of temperature and normal stress on different types of HMA–steel interfaces. The results showed that reinforced steel interfaces guaranteed higher performance than did smooth interfaces, especially with increasing temperature. Reinforced steel interfaces can be considered as a reliable solution in cases of high-shear traffic-induced stresses.