Laboratory evaluation of double-layered pavement structures for long-span steel bridge decks

The long-span steel bridge has experienced a rapid growth in China during the last two decades. Steel deck surfacing plays an important role in the durability of long-span steel bridges. So far, three types of surfacing materials have been used in China's experience: epoxy asphalt (EA), Gussasphalt (GA), and stone matrix asphalt (SMA). Four main double-layered surfacing structures have been used via the combination of the three materials, GA-EA (EA on the top), GA-SMA, EA-SMA, and EA-EA. The objective of this study is to identify the best surfacing strategy from the four existing double-layered structures. A comprehensive performance evaluation was conducted to achieve this goal. The rutting resistance, low temperature performance, fatigue performance, and moisture damage resistance were evaluated for the individual surfacing materials, double-layered surfacing structures, and the composite structures consisting of steel deck and surfacing structures. The results showed that EA-EA had the best high-temperature performance, GA-EA had the best low-temperature performance, GA concrete had the lowest moisture susceptibility, and GA-EA possessed the best fatigue performance. In addition, the layer position had an influence on the rutting performance of the double-layered structure. Then, a simple ranking method taking account into the comprehensive performance was used to identify the best surfacing strategy. The GA-EA structure was found to be the best surfacing strategy for long-span steel bridges in China after the comparison.