1. Introduction
Steel bridges, such as cable-stayed and suspension bridges, are widely used for long spans due to their high load-bearing capacity, fabrication precision, and fast installation. The steel bridge deck pavement acts both as a structural layer and a service surface, protecting the orthotropic steel deck from corrosion and mechanical damage while providing durable performance for traffic. Its thermomechanical behavior directly affects vehicular safety, ride comfort, and the long-term durability of the bridge. Key factors that influence its performance include the modulus compatibility between pavement materials and the steel deck, surface smoothness, and resistance to fatigue under environmental and traffic loads [
1]. Unlike conventional subgrade-supported pavements, steel bridge deck pavements exhibit much more complex thermo-mechanical coupling behavior, characterized by multi-axial stress states under moving loads and surface temperatures rising to 60–70 °C during summer. This unique service environment results from the combined effects of constrained thermal expansion in orthotropic steel decks and amplified dynamic vehicle loading on low-stiffness pavement systems [
2]. Conventional bridge deck systems typically use asphalt concrete pavements with bituminous or resin-based bonding materials, both of which show significant temperature-dependent performance variations [
3]. Under different environmental factor and vehicle load conditions, steel bridge deck pavements are susceptible to distress, such as rutting and displacement, imposing strict requirements on the materials used for the pavement layer [
4,
5,
6].
As a result, bridge deck pavement materials must meet enhanced thermal stability criteria. Three main conventional systems are commonly used, including cast asphalt mixtures, double-layer modified asphalt systems, and epoxy asphalt composites [
7]. The Guss Asphalt and double-layer modified asphalt systems exhibit insufficient high-temperature performance in practical applications. In contrast, the epoxy asphalt pavement system, while offering superior performance, is limited by significantly higher implementation costs [
8,
9,
10]. Researchers have also attempted to use poly methyl methacrylate and polyurethane asphalt materials in structural layers. While the poly methyl methacrylate bridge deck pavement system exhibits excellent performance, it incurs higher costs. Conversely, the polyurethane asphalt system offers better mechanical properties and easier construction, but its high-temperature performance is relatively inferior [
11,
12].
However, the high thermal conductivity of steel, its sensitivity to temperature changes [
13], and the complex service environment of steel box girder bridges result in significant differences in the service conditions of the asphalt mixture in the pavement layer compared to traditional asphalt pavements. To accurately assess the temperature impact on steel bridge decks, it is necessary to determine an appropriate temperature field for the bridge deck pavement layer [
14]. Although in situ monitoring provides a realistic characterization of bridge deck pavement temperature fields, its application is often constrained by insufficient data sampling and limited engineering feasibility. Specifically, temperature field detection on in-service bridge pavements faces significant operational challenges due to traffic interference and limited opportunities for sensor deployment [
15]. Consequently, researchers have adopted computational modeling approaches to simulate temperature field distributions, thereby successfully deriving validated evolution patterns of pavement layer temperature gradients that align with empirical observations [
16,
17,
18,
19]. Liu et al. developed a thermomechanical coupling model for steel box girders grounded in transient heat transfer principles, implementing the element activation/deactivation technique to precisely replicate the phased construction process of Guss Asphalt mixture placement, with particular emphasis on thermal–structural interaction mechanisms during material deposition [
20]. Zhou et al. formulated a three-dimensional coupled heat transfer model for steel box girder–pavement layer systems using ABAQUS finite element analysis, integrating thermal conduction principles to quantify interfacial thermomechanical interactions. Their computational framework successfully decoupled the thermal response mechanisms between structural components under diurnal temperature fluctuation conditions, revealing critical phase lag characteristics in heat flux propagation across material interfaces [
21]. However, current studies on temperature field analysis have primarily focused on external environmental factors, with limited research on the internal thermal conditions within steel box girders.
The ERS bridge deck pavement system employs a three-layer structure that comprises an Epoxy-Bonding Chip Layer (EBCL), cold-mixed resin asphalt mixture (RA), and Stone Mastic Asphalt (SMA) [
10]. The ERS pavement system demonstrates superior performance with ambient temperature construction feasibility, reduced technical demands, and rapid serviceability after minimal curing. Notably, its exceptional waterproofing characteristics, combined with its facile maintenance for distress remediation and cost-effectiveness, endow this system with substantial application potential in bridge engineering practice. Current practices in ERS bridge deck pavement applications predominantly rely on empirical experience and precedent construction cases for parameter determination across structural layers. The ERS bridge deck pavement system uses resin materials as the core, with the upper layer typically consisting of SMA mixtures. This system is characterized by susceptibility to high-temperature distress. However, there is limited research on this topic, so it is important to focus on the impact of temperature on the performance of the ERS bridge deck pavement system [
22,
23]. When investigating the performance of the ERS pavement system, it is essential not only to validate the high-temperature performance of the materials in each structural layer but also to study the overall high-temperature performance of the composite structure, ensuring that it aligns with the actual bridge deck environment.
Therefore, this paper uses finite element analysis software COMSOL Multiphysics 6.2 (trial version) to establish a three-dimensional model of the steel box girder and pavement layer. Using simulations, the high-temperature field of the bridge deck pavement layer at different times of the day is calculated, while also considering the influence of airflow velocity inside the steel box girder on the temperature field. Unlike most previous studies that considered only external environmental temperatures, this study incorporates internal airflow effects. In addition to verifying the high-temperature performance of pavement materials through rutting tests, this study further combines the simulated temperature field with modified dynamic creep tests conducted on the composite structure under extreme thermal conditions, aiming to evaluate the overall high-temperature deformation resistance of the ERS steel bridge deck pavement system. Prior studies often focused solely on the material-level performance of epoxy–asphalt composites, whereas this work emphasizes structural-level validation of the composite system under realistic thermal conditions. The aim is to verify the rationality of the ERS pavement system as a dual-layer heterogeneous structure capable of resisting high-temperature deformation on steel bridge decks. Furthermore, measures to mitigate high-temperature distress in the steel bridge deck pavement layer, without altering the stiffness and strength of the box girder, are proposed.
4. Conclusions
This study investigates the high-temperature performance of ERS steel bridge deck pavement materials and calculates temperature fields through numerical simulations, yielding three principal conclusions:
(1) Under summer high-temperature conditions, the bridge deck pavement layer experiences significantly higher temperatures than the ambient air, with the peak surface temperature reaching up to 70 °C. This places greater demands on the high-temperature stability of pavement materials. The peak temperature at the bottom surface can reach 65 °C, necessitating strict assurance of bonding strength and shear resistance under elevated temperature conditions. Accordingly, it is recommended to raise the testing temperature for evaluating the high-temperature performance of pavement materials in steel bridge deck systems to approximately 70 °C.
(2) Laboratory results confirm the excellent high-temperature resistance of the ERS pavement system. The RA05 mixture achieved a dynamic stability of 22,318 cycles/mm at 70 °C, representing a 64–218% improvement over conventional materials. The SMA-13+RA05 composite structure sustained more than 7000 loading cycles, with rutting resistance more than twice that of traditional systems, primarily due to the superior properties of the RA05 layer.
(3) Enhancing internal airflow within the steel box girder effectively reduces peak pavement temperatures and high-temperature exposure durations. When the internal airflow matches ambient wind speed (open-girder configuration), surface temperatures can be lowered by up to 20 °C, and high-temperature durations can be shortened by 3–7 h. Implementing ventilation openings is thus an effective strategy to mitigate thermal stress without compromising girder stiffness or strength.