Contact behaviors of steel‐formed concrete and autoclaved aerated concrete interfaces in prefabricated structures

AbstractAutoclaved aerated concrete (AAC) wall panels, valued for their lightweight properties, low carbon footprint, and ease of processing, are commonly combined with precast concrete beams and columns to form prefabricated structures with significant potential in residential construction. The rough interfaces between concrete and AAC components play a critical role in load transfer and seismic energy dissipation. This study examines the contact mechanical behavior of steel‐formed concrete and AAC panel interfaces. Laser microscopy was employed to capture the actual surface morphology of both materials, and normal compressive contact and tangential friction tests were conducted on AAC‐to‐AAC and AAC‐to‐concrete interfaces. The W‐M fractal model was used to simulate and generate rough surfaces, while finite element analysis in Abaqus was performed to investigate surface behavior, including actual contact area, material damage, tangential sliding stiffness, and friction coefficient. The results indicate that both AAC and concrete surfaces exhibit self‐affine fractal characteristics, with the bi‐fractal model effectively capturing concrete surface roughness within the scanning scale range. For both interface types, the actual contact area increases with contact pressure. The closure deformation of the contact surfaces initially increases linearly with normal stress, followed by a gradual reduction in growth rate before stabilizing at a constant value. The relationship between normal compressive stress and closure deformation is best described using a two‐stage model combining linear and polynomial functions. Under tangential shear loading, small tangential forces induce relative sliding at the interface, with the friction coefficient increasing elastically with slip displacement. At full plasticity, the tangential friction coefficient stabilizes at 0.76 for AAC‐to‐AAC interfaces and 0.65 for AAC‐to‐concrete interfaces. Parametric analysis further reveals that AAC material strength has minimal influence on surface friction performance.