Desenvolvimento de painéis sanduíche leves com compósitos cimentícios reforçados com tecidos vegetais

Abstract

The main objective of this research is to develop lightweight sandwich panels with external faces in cementitious composites reinforced with natural fiber fabrics extracted from pineapple leaves and jute stems, with a core in lightweight material such as Extruded Polystyrene (XPS), which, when subjected to physical and mechanical tests, are resistant to compression, traction and flexural stresses, in addition to promoting thermal comfort. The use of vegetable fiber fabrics in the conformation of the faces of the sandwich panels in cementitious composites improves the alignment and direction of the fibers, increasing the mechanical performance of the panels in the direction and sense of the stresses. The pineapple fibers, bundles and fabrics were subjected to autoclaving, alkaline and hybrid treatments to reduce water absorption and dimensional variation of the natural fibers, improving the performance of the composites. To analyze the interface between the cementitious matrix and the fiber, pullout tests were performed on bundles and fabrics of pineapple fibers, in natura and treated, with embedded lengths equal to 10, 20 and 30 mm. To reduce the delamination that sandwich panels are subject to due to the different properties of the materials used in the core and face, this research studied four configurations at the core-face interface, with the configuration with parallel grooves being the one that obtained the best mechanical performance. Panels were also molded with varying the number of reinforcement layers on the face from 1 to 5, in order to analyze the influence of the number of reinforcement layers on the face on the performance of the sandwich panels. With the results of the tests on the fibers, bundles, fabrics, plates and sandwich panels, it was verified that the type of fiber used in the production of the reinforcement fabric and the type of interface between the core and the faces of the sandwich panels are preponderant factors in the behavior, performance and cracking pattern of the sandwich panels. At the end of this research, the Sandwich Panels showed adequate mechanical and thermal behavior to be used as structural, semi-structural and sealing elements.