Potencial da utilização de resíduos de tubos de papel kraft na produção de painéis de cimento Portland

Abstract

Wood-cement panels are composed mainly of cement, wood, water and a curing accelerator additive. This study aims to investigate the use of waste from the company Tubominas in the manufacture of these panels, replacing wood, partially or totally, with waste from kraft paper tubes (RTK). Panels were produced with different proportions of wood and waste: 100% wood (reference), 50% waste and 50% wood, 100% waste and 100% waste with 1% polypropylene (in relation to cement). Initially, chemical and physical tests were performed on the wood and waste, in addition to morphological tests on the fibers (wood, waste and polypropylene). The preparation of the composites for the panels followed the proportion 1:0.37:0.06:0.50 (cement:wood:additive:water) and was done in a mechanical concrete mixer. The panels were produced by automatic hydraulic pressing at room temperature, applying 4 MPa of pressure for 10 minutes, and remaining clamped for a period of 24 hours to maintain the pressure. After 28 days of curing, the panels were subjected to physical characterization tests (density, water absorption, swelling in thickness), mechanical tests (strength and stiffness in flexure, internal bonding and compression) and microstructural tests. The comparison between the wood and the waste showed that the latter has more favorable characteristics for application in the panel. However, the tests indicated that the addition of waste reduced the overall mechanical resistance of the panels, although the tensile strength in flexure remained within the normative standards. The incorporation of polypropylene fiber significantly increased the tensile strength in flexure, even exceeding the values observed in the reference panel.