Otimização de formulações para produção de telhas de concreto com resíduo de mineração reforçadas com materiais poliméricos e lignocelulósicos

Abstract

Brazil has one of the largest iron ore reserves in the world. With the growth of the global population and its increasing consumption demands, combined with the growing needs of steel processing industries, there is also an increase in the generation of waste, requiring new techniques for material reuse. This helps avoid final disposal in containment dams, as the collapse of these dams has caused environmental and social damage worldwide in recent decades. The research evaluated the total replacement of limestone powder (PPC) and partial replacement of cement with iron ore waste (RMF) in concrete roof tiles reinforced with polymeric and lignocellulosic residues. The control treatment used 27.15% cement, 60.85% sand, and 12% PPC. Other treatments tested different proportions of PPC and cement replacement with RMF, and the use of polypropylene (PP), PET, and pine wood residues (0.5% each) as reinforcements.The tiles were cured for 28 days and evaluated for physical, mechanical, thermal, acoustic, and microstructural properties before and after accelerated aging. The economic viability was also analyzed. The results concluded that replacing both PPC and cement with RMF in distinct formulations had a positive impact, mainly in increasing mechanical resistance after aging, as well as reducing production costs and maintaining thermal and acoustic properties. The incorporation of PP and PET increased costs, but PP improved the mechanical properties, while pine fibers, although economical, reduced mechanical resistance and increased thermal conductivity.The simultaneous replacement of PPC and cement with RMF resulted in increased water absorption and porosity, with a slight reduction in density and dry weight. RMF also improved flexural strength after aging while maintaining low costs. Thermal conductivity increased initially but reduced after aging, while acoustic performance showed a slight decrease. The ASTM C1492-3 standard was fully met for all treatments. The use of pine in RMF formulations stood out due to the increased flexural strength after aging and cost reduction. PP-reinforced tiles showed the best flexural strength results without RMF, followed by PET. Both materials, despite increasing production costs, showed improvements in acoustic insulation at 28 days of curing.