Full-Scale Experimental Study on Temperature Field Distribution of PBL-Based Steel–UHPC Composite Structures during the Early Stage and Steam Curing Period

As one of the most innovative cement-based engineering materials, ultrahigh-performance concrete (UHPC) has attracted increasing attention in civil engineering over the last few decades. Recently, a new steel–UHPC composite bridge deck that uses perfobond strips (PBLs) to enhance the connection between the steel plate and the UHPC layer instead of the studs is proposed. Since UHPC uses large amounts of cementitious materials with low water–cement ratios, its hydration heat release and total shrinkage are much greater than normal concrete. To speed up construction and eliminate shrinkage during operation, UHPC components are usually cured using high-temperature steam. For composite structures consisting of two or more materials with different linear expansion coefficients, rapid changes in the temperature field of components caused by high-temperature steam curing may decrease the interface bonding strength and generate relatively larger initial stress or even crack. Therefore, it is necessary to investigate the influence of high-temperature steam curing on the initial stress of the proposed PBL-based steel–UHPC composite structures. Prior to this, it is necessary to understand the temperature field distribution on the PBL-based steel–UHPC composite structures under high-temperature steam curing conditions. In this work, a full-scale (7 m × 38 m) experiment on temperature field distribution of the PBL-based steel–UHPC composite structures was carried out. The time-varying temperature field distribution and the temperature gradient effect were experimentally observed. In addition, based on ABAQUS (version 2021), a fast explicit simulation method was adopted to simulate the temperature field distribution of the composite structures, which shows a good agreement with the measured results. Compared to the traditional implicit simulation method, the calculation efficiency is improved by 66.7% with considerable accuracy. Moreover, a parametric analysis is presented to investigate the distribution pattern of temperature considering factors such as molding temperature, ambient temperature, and steam curing temperature. This study provides a comprehensive analysis of the temperature field changes in steel–UHPC composite structures and can provide a basic reference for the subsequent initial stress analysis of composite structures.