Composite interaction and structural performance of reinforced concrete sandwich panels with textile waste core

Abstract

The growing demand for lightweight, energy-efficient, and sustainable construction systems has stimulated the development of sandwich panels incorporating waste-derived materials. This study investigates the structural and multifunctional performance of reinforced concrete sandwich panels (RCSPs) incorporating compacted textile waste blocks as a low-stiffness deformable core. Unlike conventional foam-based systems, the proposed configuration employs a compliant core that governs the structural response through transverse shear deformation and partial composite interaction between the concrete face sheets. Panels with total thicknesses of 3, 4, and 5 in. were experimentally evaluated under compression, bending, diagonal tension, thermal conductivity, fire exposure and impact loading, and compared with monolithic reinforced concrete panels (RCPs). The results demonstrate that the structural behavior is governed by the balance between face-sheet bending stiffness and core shear stiffness, which controls the degree of composite interaction. Flexural and impact performance exhibited a non-monotonic dependence on core thickness, with the 4-in. RCSP achieving the optimal structural efficiency due to improved composite interaction, whereas thicker cores promoted excessive shear deformation and reduced structural efficiency. Compared with RCPs, RCSPs exhibited higher ductility (42–48%), delayed crack localization, lower peak impact accelerations, and greater energy absorption resulting from progressive core compaction and distributed cracking. Furthermore, the textile waste core reduced thermal conductivity by 26–37%, increased thermal resistance by 35–58%, and decreased panel density by 21–36%, thereby improving the strength-to-weight efficiency of the sandwich system. Although reductions in compressive strength, diagonal shear capacity, and fire resistance were observed, these were compensated by enhanced deformation capacity, energy dissipation, and thermal insulation performance. The findings demonstrate that textile waste blocks provide an effective deformable core for reinforced concrete sandwich panels, offering a sustainable alternative to conventional core materials while enabling lightweight structural systems with improved thermal performance and efficient recycling of textile waste.