Programa de Pós-Graduação em Engenharia de Infraestrutura e Desenvolvimento Energético - PPGINDE/NDAE/Tucuruí
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/9400
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Navegando Programa de Pós-Graduação em Engenharia de Infraestrutura e Desenvolvimento Energético - PPGINDE/NDAE/Tucuruí por Orientadores "SOUZA, Paulo Sérgio Lima"
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Item Acesso aberto (Open Access) Avaliação do emprego de agregado miúdo reciclado na produção de peças pré-moldadas para pavimentação tipo “paver”(Universidade Federal do Pará, 2021-02-05) VIEIRA, Marília de Oliveira; SOUZA, Paulo Sérgio Lima; http://lattes.cnpq.br/4933212993218783Item Acesso aberto (Open Access) Influência no comportamento mecânico do concreto com a utilização de microfibras de polipropileno para redução do efeito de retração: um estudo realizado em Belém do Pará(Universidade Federal do Pará, 2022-10-27) CUNHA, Wictor Alencar; SOUZA, Paulo Sérgio Lima; http://lattes.cnpq.br/4933212993218783Seeking to mitigate the effect of concrete shrinkage, the influence on the mechanical behavior of concrete reinforced with polypropylene microfibers was studied in this study. In the experimental program, 15 (fifteen) study series were produced: one reference without the addition of polypropylene microfiber for each w/c ratio studied, totaling 3 series; and another 12 (twelve) series with the following characteristics: addition of 0.6% and 1.0% of microfiber content varying the length in 12 mm and 25 mm, the w/c ratios being studied with values of 0.45 ; 0.55 and 0.65. Tests were carried out in the fresh state of the concrete to evaluate consistency and workability; and in the hardened state to evaluate compressive strength, flexural traction and modulus of elasticity with age of the specimens at 7 and 28 days; and dimensional variation with age of 48h, 7 and 28 days. The results obtained were studied through analysis of variance (ANOVA) and the Tukey test to determine the statistical significance of the responses found. It was concluded that the optimum content of addition of polypropylene microfiber to concrete was 1.0% with fibers of 12 mm length and w/c ratio=0.55.Item Desconhecido Reação álcali-agregado: potencial reativo dos agregados miúdos provindos das jazidas dos municípios de Ferreira Gomes, Macapá e Porto Grande no estado do Amapá(Universidade Federal do Pará, 2024-02-29) FIGUEIREDO, Rodrigo Francklin Lopes; SOUZA, Paulo Sérgio Lima; http://lattes.cnpq.br/4933212993218783The concrete is one of the most employed materials in engineering, its performance and durability can be altered by various deterioration processes, making it essential that materials used in its composition be analyzed and suitable for each type of construction. Among these processes, there is the alkali-aggregate reaction (AAR), which is defined as a chemical process that occurs between the alkaline components of cement and certain types of reactive aggregates, which can result in the emergence of expansive products that cause structural damage to concrete (Neville, 1997). The objective of this work is to analyze the reactive potential of fine aggregates, specifically the alkali-reactive potential of 8 sand samples from the main deposits in the municipalities of Ferreira Gomes, Macapá, and Porto Grande in the state of Amapá (AP). The motivation for this research arose due to the lack of data regarding the reactivity of fine aggregates in the state and as a preventive measure against the occurrence of alkali-silica reaction (ASR). For this evaluation, the first test used was the accelerated mortar bar method following NBR 15577 - 4 (ABNT, 2018). In addition to this, the chemical method following NBR 9774 (ABNT, 2008) was employed as an auxiliary, as well as scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS) attached, in order to observe the microstructure of the bars, verify the presence or absence of products that evidence the occurrence of AAR, and through semi-quantitative elemental chemical analysis, identify the substances present in the bars. The results indicated in the accelerated method that the collected samples do not have deleterious potential, as the bars did not reach 0.19% expansion; the highest percentage of expansion was 0.12% in the Translima Deposit (J7), this innocuous behavior was confirmed with the use of the chemical method. Regarding the use of SEM, the formation of the gel related to ASR was not observed. Finally, the mapping of reactive aggregates was carried out, and it was found that the aggregates are innocuous and can be used satisfactorily regarding ASR.Item Desconhecido Utilização de rejeito de minério do cobre como agregado miúdo na produção de concreto(Universidade Federal do Pará, 2019-03-29) SOUSA, Douglas Martins; SOUZA, Paulo Sérgio Lima; http://lattes.cnpq.br/4933212993218783A major concern with recent accidents involving tailings dams has again raised the urgent need for mining companies to adapt to the fate of ore tailings generated by their operations. In this context, the reuse of these materials in the construction industry shows itself to be an excellent alternative. In this research, it was evaluated the reuse of copper mining waste as a partial substitute for the small aggregates in the production of conventional concretes, aiming the evaluation of the mechanical performance of the concrete produced with this material, also if it is objective, to obtain a material destination sustainable for this material. Only in the mine where the material was collected, is there about 160 million tons of this material accumulated in the mine tailings basin, which shows that there is a considerable source of this material available for reuse. In the experimental program there were four study series: one reference composed of concrete without the addition of the tailings, and another three with 15%, 30% and 45% of substitution to the small aggregates, besides the use of two water ratios /cement. Fresh tests were carried out to evaluate the influence of the reject on the plastic properties of the concrete, and in the hardened state, test specimens were tested at 07 and 28 days for the axial compressive strength, diametral compression traction, traction in flexion and modulus of elasticity. The results obtained were statistically treated through analysis of variance (ANOVA) and proved for the substitution parameter of reject, there was significance. The results showed that the samples with substitution of tailings obtained good results, significantly increasing both the tensile strength and the compressive strength of the concrete when compared with reference series under the same conditions. Therefore, copper reject shows an excellent potential to be reused in the production of concrete, with respect to its effects on the mechanical properties of the concrete, in addition to achieving a more sustainable destination than today.