Teses em Engenharia Civil (Doutorado) - PPGEC/ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/9887
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Navegando Teses em Engenharia Civil (Doutorado) - PPGEC/ITEC por Orientadores "MACEDO, Alcebíades Negrão"
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Item Acesso aberto (Open Access) Aplicação de madeiras amazônicas em elementos de madeira lamelada colada (MLC)(Universidade Federal do Pará, 2023-03-16) NEVES, Paulo Henrique Lobo; MOUTINHO, Victor Hugo Pereira; http://lattes.cnpq.br/8464600937488553; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179Timber is considered on the world stage as the primary building material of the 21st century. However, for this potential to be actualized, technologies for unfolding and using the raw material, such as Glued Laminated Timber (glulam), need to be disseminated and used in a wider range of species. In this regard, we emphasize that, despite the great existing diversity, only some studies are found to verify the potential use of Amazonian timber in glulam. This way, this paper aims to analyze the gluing of ten species native to the Amazon, namely: Jacaranda sp., Simarouba amara Aubl., Astronomium lecointei, Couratari sp., Cedrela fissilis., Cordia Goeldiana Huber, Hymenaea courbaril., Dipteryx odorata. Euxylophora paraensis., Mezilaurus itauba., and the combination with four different types of adhesives, two structural resistant to moisture and two non-structural, using a shear sample of solid timber as a evidence, with a minimum of 20 repetitions per treatment. Complementary tests such as delamination and static bending were carried out. We verified that for some species there was an adhesive with statistically equal and superior resistance in some combinations compared to the control sample, demonstrating that the studied species have the potential for the production of glulam, as well as for other products that use adhesives.Item Acesso aberto (Open Access) Concreto permeável geopolimérico aplicado na pavimentação(Universidade Federal do Pará, 2023-03-07) ARAÚJO, Wendel Melo Prudêncio de; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179In the recent scenario, groundwater retention plays a key role in achieving environmental sustainability. This can be achieved by using pervious concrete as a paving material in roads, parking lots, garden areas and low traffic road applications. Due to its mechanical limitation, much research has been carried out to develop a more resistant material. Geopolymeric permeable concrete is synthesized by the alkaline activation of materials rich in aluminate and silica in an alkaline medium. This work aims to produce samples of geopolymer permeable concrete, using red ceramic residue and metakaolin as precursors, for application in permeable paving. The results showed that the use of red ceramic in the production of pervious geopolymer concrete up to a concentration of 30% is feasible, since higher concentrations can compromise the physical, hydraulic and mechanical properties.Item Acesso aberto (Open Access) Emprego de Resíduo de Silício Metálico como Material Pozolânico na Produção de Cimento Portland Composto(Universidade Federal do Pará, 2022-12-19) CUNHA, Rodrigo Rodrigues da; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179Civil construction, despite being an extremely important sector for the country's economic development, consumes a very significant amount of natural raw materials, in addition to being responsible for most of the consumption of cement produced in the world. The production of this material, in turn, causes many environmental impacts, resulting mainly from the sintering stage of clinker (main constituent of cement), which causes the emission of thousands of tons of CO2 into the atmosphere. In this sense, several studies have been carried out in order to point out an alternative material that can be used as a mineral addition to cement instead of clinker. Much of this research has sought to study the use of additions manufactured from the use of industrial waste. Given this context, the present work aims to analyze the behavior of a modified Portland cement of the CPIIZ-32 type, produced with partial replacement of clinker, by a residue from the pre-separator of the ferrosilicon - metallic silicon manufacturing process. - from an industry located in Breu Branco/PA. Therefore, at first, the physical and chemical characterization of the residue in natura and processed form was carried out, through the milling process, from the specific mass, FR-X, DR-X and activity index tests. pozzolanic with lime and cement. Then, 5 (five) blends of composite cement were formulated with different contents of ground silicon metal residue to analyze the mechanical behavior at 28 and 90 days of curing. Finally, a comparison was made of the physical-mechanical performance of the mortars produced with the use of modified cement and commercial cement of the CPIIZ-32 type. The results showed that the metallic silicon residue, after going through a pre-benefiting process (grinding for a period of 60 minutes) obtains properties consistent with the requirements stipulated by NBR 12653 (ABNT, 2014) to be considered as a pozzolanic addition. The use of this by-product for this purpose can generate enormous environmental benefits, reducing the impacts resulting from the clinker production stages, as well as being a viable alternative for the reverse logistics of this material, since the generating companies still do not have any form of reuse for this residue.