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 "Agregados (Materiais de construção)"
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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.Artigo de Periódico Acesso aberto (Open Access) Efeitos do tipo, tamanho e teor de agregado graúdo no módulo de deformação do concreto de alta resistência(2011) POMPEU NETO, Bernardo Borges; OLIVEIRA, Dênio Ramam Carvalho de; RAMOS, DanielleConcrete, material with heterogeneous and complex composition, is the main structural material applied in the construction industry. From the structural point of view its main property is the mechanical strength. The behavior of concrete based on conceptual studies of granular resistance can lead to a safer structural design and better use of the material. This paper presents the results of a study conducted to evaluate the effects of type, size and content of coarse aggregates on the modulus of deformation of high strength concretes. The concrete mixture studied contains basalt or granite aggregates with maximum dimensions of 9.5 mm and 19.0 mm and water/cement ratio of 0.35. The deformation modulus of the material was determined using the linear length of Load-CMOD curve (displacement of the crack mouth opening) from three point bending tests performed using a middle span cracked beam, following the propositions made by the RILEM 89-FMT technical committee.