Stud connections in steel and recycled concrete composite structures: Short-term and long-term behavior

The world is experiencing ecological environment degradation and accelerated resource depletion. Effective utilization of construction waste through crushing and processing into recycled aggregates for recycled concrete production can alleviate environmental pollution and resource depletion and bring considerable economic benefits. Existing findings cannot be directly applied to stud connectors in steel and recycled concrete composite structures. The structural properties of stud connectors in steel and recycled concrete composite structures have yet to be adequately investigated, especially for the long-term structural behavior. Therefore, this paper presents comprehensive research on the short-term and long-term behavior of stud connections in steel and recycled concrete composite structures with experimental, numerical, and theoretical methods. The most significant effects on the ultimate bearing capacity are observed for stud diameter, followed by the coarse aggregate replacement ratio, and the influence of stud length is the least. Furthermore, three characteristic evolutionary phases of long-term behavior with significant engineering references are defined. A highly positive correlation is found between the coarse aggregate replacement ratio and the long-term structural deformation, creep rate, and creep coefficient. Finally, the parametric studies of seven critical parameters are carried out through the numerical approach to generalize the extensiveness of present findings, and the influence extent of each parameter on the long-term structural behavior is evaluated by parametric sensitivity analysis. Research findings can serve as an important reference for future research on steel and recycled concrete composite structures and provide essential guidance for the design and optimization of engineering structures.