Exploration and Investigation of Recycled Aggregate Concrete Beam Performance Under Long-Term Loading

Abstract This study investigates the long-term structural behaviour of reinforced concrete beams incorporating recycled aggregates using advanced finite element analysis. Diana FEA software was employed to develop numerical models calibrated against experimental data from two published investigations, incorporating the FIB Model Code 2010 constitutive framework to represent recycled aggregate concrete characteristics. The computational methodology replicated experimental protocols including loading configurations, environmental conditions, and material properties. Following validation, the models demonstrated excellent predictive capability for long-term deflection behaviour, crack propagation, and creep recovery mechanisms. A parametric analysis examined the influence of concrete strength (30–70 MPa), reinforcement ratios, sustained loading, and environmental conditions. Significant findings emerged regarding time-dependent performance. Specimens exhibited a 31% reduction in deflection ratio after 90 days of sustained loading and 23% creep recovery within 10 days of load removal when concrete strength increased from 30 to 70 MPa. Elastic recovery remained independent of reinforcement ratio, whilst higher reinforcement ratios reduced creep recovery capacity. Traditional experimental approaches for predicting long-term structural behaviour are often time-consuming and resource-intensive, limiting their practical application in design processes. These findings provide crucial insights into recycled aggregate concrete beam performance, supporting sustainable construction implementation. The validated numerical framework offers a robust and efficient tool for predicting service-life behaviour of environmentally conscious structural elements, significantly reducing the time and cost associated with conventional experimental prediction methods whilst maintaining accuracy and reliability.