Novel flexural behaviour of sandwich structures made of perlite foam/sodium silicate core and paper skin

A sandwich structure consisting of perlite composite foam as core and Brown paper as skin is developed and its flexural behaviour is studied in relation with properties of constituents and manufacturing variables of perlite composite foam core consolidated with sodium silicate binder by compaction. Tensile properties of Brown paper coated with binder were affected by sodium silicate content in diluted binder. The best performance of the Brown paper was found for strength and energy absorption when coated with undiluted binder. The sandwich structure was fabricated with the best performed Brown paper and perlite composite foam cores with various binder contents and compaction ratios. The performance of the sandwich structure for core shear strength, skin normal strength, and stiffness was similarly affected by manufacturing variables to those of perlite foam core. Load carrying capacity of perlite foam core reinforced with Brown paper for the sandwich structure was increased about 3-7 times the unreinforced one depending on how binder and compaction ratio are combined for manufacturing perlite foam core. The flexural failure of perlite composite foam core was initiated from the tension side of the flexural specimen. However, when the foam core was sandwiched with the Brown paper, the failure initiation site was shifted to the mid-plane of flexural specimen.