Artigos Científicos - FEC/ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2789
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Navegando Artigos Científicos - FEC/ITEC por Assunto "Amazônia brasileira"
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Artigo de Periódico Acesso aberto (Open Access) Chapas de cimento-madeira com resíduos da indústria madeireira da Região Amazônica(2012-06) MACÊDO, Alcebíades Negrão; SOUZA, Alberto Alexandre Costa e; POMPEU NETO, Bernardo BorgesThe aim of this study was to to evaluate the use of waste from the timber industry of the Brazilian Amazon Region in the production of wood-cement composites. The compatibility of six Amazon hardwood native species with cement CP V ARI was assessed through axial compression tests in cylindrical specimens. The waste was used was only treated by washing in hot water for two hours. The ratio cement/wood was 3:1 in mass, along with aluminum sulfate curing accelerators at 3%, and calcium chloride curing accelerators at 3% and 5%. The results of the axial compression tests indicated the potential use of waste for three species combined with calcium chloride curing accelerator treatment at 5%. Wood-cement particleboards were made with waste of the species Cedrela odorata L. (Cedar), Vochysia maximum Ducke (Quaruba), Hymenaea courbaril L. (Jatoba) and a mixture of them. The test results of the physical and mechanical properties of the particleboards showed that all had adequate characteristics for the purpose, and the Cedar species particleboards presented the best performance.Artigo de Periódico Acesso aberto (Open Access) Concretes with red mud coarse aggregates(2012-06) OLIVEIRA, Dênio Ramam Carvalho de; ROSSI, Carlos Rodrigo CostaRed mud (RM) is a mineral waste, residue of the Bayer process used to obtain alumina from bauxite. While the exploration of rolled pebble damages the environment and is much more controlled by the government, the huge RM disposal areas do not stop increasing and polluting soil, rivers and groundwater sources in Amazon. In this work, the material mixtures used to produce coarse aggregates presented up to 80% of RM, 30% of metakaolin and 30% of active silica as recycled waste. Several tests were carried out to determine the aggregates physical properties and to evaluate the mechanical performance of the concretes with the new aggregates, including hydraulic abrasion strength, and the results were compared to the reference ones, i.e. rolled pebble concretes. Additionally, the sintering process neutralizes any toxic substance as occur in some RM products like tiles and bricks, and these results have encouraged an industrial or semi-industrial production of RM aggregates for concretes.