Flexural performance and failure analysis of fine aggregate concrete wire mesh reinforced autoclaved lightweight concrete sandwich composite panels

Autoclaved lightweight concrete (ALC) is widely utilized in sustainable construction due to its low carbon footprint and excellent thermal properties, yet its inherent brittleness and low tensile strength limit its structural applications. To overcome these deficiencies, this study proposes a fully‐cementitious sandwich composite panel featuring an ALC core, fine‐aggregate concrete (FAC) face sheets, and steel wire mesh. Flexural performance and failure mechanisms were evaluated through four‐point bending tests and high‐fidelity finite element (FE) modeling using concrete damaged plasticity and cohesive elements. The FE model demonstrated excellent accuracy with a 5.04% average error. Results identify three failure modes: rebar rupture, ALC shear failure, and interfacial peeling. While increasing the reinforcement ratio enhances stiffness and load capacity, it triggers a transition from flexural‐dominated failure to brittle interfacial debonding. Additionally, a theoretical model based on beam on elastic foundation theory was developed to quantify interfacial peeling stress. This research establishes a robust analytical framework and design guidelines for the structural optimization of high‐performance ALC composite systems.