ABSTRACT
The concrete slabs in the negative moments region of continuous steel-concrete bridge structures are generally tense and easy to crack. There are difficulties in high-temperature steam curing of the commonly used ultra-high-performance concretes (UHPCs) on site. In this study, the cracking resistances of the negative-moment regions of the prefabricated steel-concrete composite beams with naturally cured UHPCs are investigated. Based on the extensive experiments, it is demonstrated that relative to traditional steel-concrete composite beams, natural curing steel-UHPC composite beams can effectively improve the negative-moment bending performance by increasing initial cracking loads and reducing crack widths of concrete slabs. The present experiments also investigate the influence of prestress on steel-UHPC composite beams under negative moments. Results show that applying to prestress to the natural curing UHPC slab is an effective method to further increase the cracking performance of the continuous steel-UHPC composite beams. Generally speaking, the research results of this study can provide a reference for the performance improvement of the negative moment zone of steel-concrete composite bridges.
