Programa de Pós-graduação em Engenharia Civil
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Navegando Programa de Pós-graduação em Engenharia Civil por Por Orientador "Figueiredo, Enio José Pazini"
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Item Resistência à corrosão dos aços CA24 e CA50 frente à ação dos cloretos(Universidade Federal de Goiás, 2014-01-24) Carvalho, Leonardo Gomes de Sá e; Figueiredo, Enio José Pazini; http://lattes.cnpq.br/4075543806767323; Figueiredo, Enio José Pazini; Bacarji, Edgar; Nepomuceno, Antônio Alberto; Costa, Valéria Conceição MouroCorrosion of reinforcement in concrete structures constitutes one of the most serious and costly problems to be solved in construction. Currently, a number of professionals are somehow mobilized in order to prevent, control and repair concrete structures subjected or with steel corrosion. This paper presents and discusses the main results of an experimental study aimed to verify the corrosion resistance of two different types of steel, CA24 and CA50. The CA24 steel was widely used in construction of the 1930s to 1960s, and CA50 steel is the most currently employed as reinforcement of concrete structures. Besides the type of steel, the study evaluated the influence of bar diameter (5mm and 25mm ) in the process of passivation, depassivation and propagation of corrosion. For the study, steel bars 5mm and 25mm, of the CA24 and CA50 were introduced in body-of-proof molded prismatic with a reference concrete. The bodies of the specimen underwent regular cycles of immersion in NaCl solution with 2 % concentration and drying. Were also shaped bodies-specimens with 3% sodium chloride in the mixing water by mass of cement. These remained initially in place with controlled humidity 55 ± 15 % and subsequently passed through cycles of immersion in clean water and drying. Monitoring for 210 days, the corrosion was evaluated by the electrochemical corrosion potential measurements (Ecorr) and polarization resistance (icorr). The concrete was monitored by measurements of surface resistivity (ρ). Before corrosion valuation, metallographic tests, chemical composition and mechanical tests for steel characterization were performed. The electrochemical mass loss were compared with the gravimetric weight loss, showing that steel CA50 to CA24 in comparison, is more susceptible to corrosion. The study also showed that steels with smaller diameter have lower corrosion resistance.Item Metodologia de inspeção em estruturas de pontes de concreto armado(Universidade Federal de Goiás, 2011-11-25) Euqueres, Priscilla; Rêgo, João Henrique da Silva; http://lattes.cnpq.br/6282100880834079; Figueiredo, Enio José Pazini; http://lattes.cnpq.br/4075543806767323; Figueiredo , Enio José Pazini; Rêgo, João Henrique da Silva; Liserre, Andrea Prado Abreu Reis; Carvalho, Alessandra LucianoThe objective this work is to develop and implement a methodology for special inspection on Concrete Bridges trough the quantitative analysis of the degree of deterioration of the structures so that it can serve as a basis for making decisions related to the rehabilitation of these structures. In order to develop and apply the methodology on concrete bridges, the existing methods of inspection of concrete structures were studied and adapted to the adapting to the concrete bridges. The methodology was based on GDE/UnB model in their latest formulation (Fonseca,2007) and adapted to the tables with the elements to be analyzed, together with the pathological manifestations that can occur in each element, timing and interventions classification of the level of deterioration and the relevant factors to each family of concrete bridges. A pilot study was proposed to validate the methodology. Results showed that there was a need for further adaptation, to consider the caculations of the degree of deterioration of both the family or the. With the changes proposed in the pilot study were made over 11 (eleven) inspections in order to validate the proposed methodology. With the results obtained it was concluded that the methodology for inspection of bridges is valid and of great importance to public organisms and surveyors to make decisions about the best time and the best item to be rehabilitated, being a single element, as a family elements, or the structure as a whole. One downside is that the methodoly for bridges with lenght greater than 70 meters most be used with caution, because the median openings are difficult to visual assessment. However the methodology can be used in order to obtain basic understanding of the visible elements, and after the intervention, we can make another more detailed analysis using not only the elements of routine inspection as binoculars, measuring tape, camera, among others, but also nautical elements, which provide the best viewing responsible for the inspection of the median elementsItem Influência do teor de argamassa e da granulometria da brita na permeabilidade e nas resistências à compressão e à abrasão de concretos permeáveis(Universidade Federal de Goiás, 2014-11-10) Mariano, Humberto Rodrigues; Figueiredo, Enio José Pazini; http://lattes.cnpq.br/4075543806767323; Aguilar, Maria Teresa Paulino; Oliveira, Janes Cleiton Alves de OliveiraRapid urbanization in Brazil produces significant impacts on the quality of life. Rains have been one of the main problems faced by managers of the environment due to the sealing of large areas in cities. This work aims to develop of permeable interlocki ng flooring that can be used in many types of flooring, such as in outdoor areas of homes, plazas, parking lots, roads and pedestrian routes traffic light vehicle traffic. The study examined the permeability of concrete made from gneiss rock with grain size rema ins in diameters (4.75, 6.3 and 9.5) mm and (4.75 and 6.3) mm and uniform particle size of 6.3 mm and 9.5 mm mortar with varying content of 30%, 33%, 35%, 40%, 42% a nd 44%. Compressive strength mortar with content of 30%, 33%, 35%, 40%, 42%, 44% and 55% and abrasion resistance with mortar content of 40%, 42%, 44% and 55%. After analyzing the results of the tests, the concrete produced with mortar content of 42% and continuous particle size of (4.75, 6.3 and 9.5) mm which was attended abrasion resistance based on NBR 12041, the compressive strength based on NBR 9781 and permeability according to standard ACI 522 to R 06 interlocked with permeable concrete floor.Item Influência da idade e cura do concreto na resistividade elétrica(Universidade Federal de Goiás, 2015-12-02) Perez, Elva Wendolyn Ramirez; Figueiredo, Enio José Pazini; http://lattes.cnpq.br/4075543806767323; Figueiredo, Enio José Pazini; Oliveira, Janes Cleiton Alves de; Silva, Izelman Oliveira daThe surface electrical resistivity of the fresh and hardened concrete states can be influenced by factors such as degree of hydration, the water / binder ratio (w / b), aggregate content and existence of armour. This study objective is to evaluate the performance and behavior of the electrical resistivity of the concrete´s surface based on the influence of hidratation process, curing time and the w/b ratio. The actual measured were divided into three groups, where C-0,81 represents the specific group with w/b ratio= 0.81 and compressive strength =20 MPa; C-0,50 is the concrete with w/b ratio= 0.50 and 40 MPa; and C-0,35 represents the concrete with the ratio of 0.35 and compressive strength of 60 MPa. The curing procedures applied to the three groups were: dry cure, cure submerged up to seven days and cure submerged up to fourteen days. This study the results showed that in the higher ratio w/b , the porosity of the sample is greater, and this increases the electrical resistivity. Regarding the dry cured concrete, it had higher resistivity vs submerged conrete. The results also showed that greater the degree hydratation in the sample the greater the resistivity.