Time-Dependent Behavior of Composite Steel–Recycled Aggregate Concrete Beams via Thermomechanical Finite Element Modeling

This paper aims to investigate the impact of recycled coarse aggregate (RCA) on the time-dependent behavior of composite steel–recycled aggregate concrete (RAC) beams. The FE models of the composite beams were established, and a parametric study was conducted to obtain the primary factors. Furthermore, the design method for predicting the long-term deflection was proposed by including the shrinkage deflection component. The results showed that the RCA replacement ratio significantly influenced the long-term deflection of composite beams; the long-term deflection of composite beams with 100% RCA increased by 3.5–17.2% compared with those without RCA. Moreover, using uniform shrinkage and creep models led to a 4.5–10.3% overestimation of the long-term deflection of the composite beams with the composite slabs due to nonuniform shrinkage and creep distributions. Finally, the proposed design procedures could accurately predict the long-term deflection of the composite steel–RAC beams, and the difference between the calculated and FE results ranged from 0.961 to 0.986.