Programa de Pós-Graduação em Engenharia Civil
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Master Thesis Estudo da pasta de cimento com substituição parcial e total da água de hidratação por manipueira(Universidade Federal do Rio Grande do Norte, 2021-07-28) Pipolo, Lisieux Feitosa Gondim; Acchar, Wilson; Silva, Vamberto Monteiro da; 67456863415; http://lattes.cnpq.br/7962325767490100; Lucena, Luciana de Figueiredo Lopes; http://lattes.cnpq.br/5893551656862490; Silva, Jaqueligia Brito da; http://lattes.cnpq.br/5948828937239319; Marques, Sheyla Karolina Justino; http://lattes.cnpq.br/3917387578549073Cement paste is the union of two inputs: water and cement. From it, concrete and mortar are prepared, which are the most consumed elements in the construction industry. Given this great demand, some questions arise about the environmental impact of the high consumption of natural resources. In this sense, researches have been developed to minimize the consumption of non-renewable goods by replacing them with products from other productive activities. Within this perspective is manipueira, a liquid by-product resulting from the pressing process of cassava roots with a high content of hydrocyanic acid and high biochemical oxygen demand. Its disposal is normally done in water bodies, causing changes in the self-purification and eutrophication capacity, or through accumulation in small areas surrounding the production site without prior treatment. Considering that in 2020 Brazil was responsible for the production of 18.96 million tons of cassava root, studies to mitigate this environmental impact are relevant. The objective of this research is to analyze the behavior of cement paste produced with manipueira as a substitute for water, in terms of physical and mechanical properties and microstructure. The materials were characterized and seven pastes prepared with different replacement contents (10%, 15%, 20%, 25%, 50%, 75%, and 100%) for analysis of properties in the fresh and hardened state. In the fresh state, the presence of manipueira caused a delay in setting time up to 66% about the reference paste and plasticizing behavior to the cement pastes in all the proposed formulations. In the hardened state, an increase in compressive strength of 28% was found in the formulation with 20% replacement, and a sharp drop in the proportions of 75% and 100% replacement when compared to the reference paste. It was also verified a decrease in specific mass, increase in the void index, and capillary absorption in all replacement ratios. From the results found, microstructural analyzes were performed on samples of 20% and 100% compositions. It was noticed the formation of hydrated silicate flakes (CSH) in the paste with 20% replacement, and late ettringite in the paste with 100%. Thus, it is concluded that the studied manipueira can be used in cement pastes replacing up to 20% of the hydration water since its properties have been improved. However, the incorporation of manipueira in higher levels of replacement harmed the cement hydration process.Master Thesis Avaliação do ciclo de vida de agregados leves artificiais produzidos com resíduo industrial e argila vermelha local (Nordeste/Brasil)(Universidade Federal do Rio Grande do Norte, 2020-10-09) Rocha, Débora Patrícia Batista da; Anjos, Marcos Alyssandro Soares dos; Lucena, Luciana de Figueiredo Lopes; ; http://lattes.cnpq.br/5893551656862490; ; http://lattes.cnpq.br/3904325866154130; ; http://lattes.cnpq.br/3372872328936393; Almeida, Maria das Vitorias Vieira; ; http://lattes.cnpq.br/7590200701773198; Nóbrega, Claudia Coutinho; ; http://lattes.cnpq.br/8208309251703934The adoption of alternative materials has become an increasingly constant practice in civil construction in the search for sustainable solutions for the conservation of natural resources. The reuse of industrial waste in new construction materials has aroused growing interest in environmental impacts of the production of recycled aggregates to replace conventional aggregates. To this end, this study sought to measure the environmental impacts resulting from the production of artificial lightweight aggregates produced with sugarcane biomass ash (SCBA) and red clay from the Northeast of Brazil through the Life Cycle Assessment (LCA) methodology. For this, an industrial production proposal was prepared with specification of the stages and equipment, with the possibility of being adapted to different regions of Brazil. The LCA procedure followed four main steps, prescribed by the ABNT ISO 14040:2009 and ABNT ISO 14044:2009 standards: definition of objective and scope, inventory analysis, impact assessment and interpretation. The system boundary went from the cradle to the gate level and includes the stages of extraction, collection and processing of raw materials and production of lightweight aggregates. The environmental impacts were evaluated for three compositions of the artificial lightweight aggregate (pure clay, 50% replacement and 90% SCBA). The compositions were studied in three locations of the factory: Itajá/RN, Goianinha/RN and Parnamirim/RN. The inventory data were processed using OpenLCA 1.10 software using the CML 2001 non baseline method and midpoint approach. The impact categories studied were: acidification, eutrophication, global warming, human toxicity, ozone depletion, photochemical oxidants, terrestrial ecotoxicity, freshwater ecotoxicity and marine ecotoxicity. The results showed that the use of SCBA in the composition of lightweight aggregates allowed a reduction of up to 87.21% in the use of red clay as a natural resource, in two of the three scenarios analyzed. The aggregate compositions using SCBA showed lesser environmental impacts (except in the category of global warming) compared to the composition of pure clay in scenarios where the location of the factory is close to where the waste is obtained. The transport stages influenced significantly in all impact categories due to the use of fossil fuel (diesel) and the results are very sensitive to transport distances. The stage of burning light aggregates is highlighted in the global warming category. This study clearly showed that lightweight aggregates with the use of industrial waste can contribute to the reduction of environmental impacts during their production. The results can support decision-making processes and the development of similar LCA studies in lightweight artificial aggregates.Master Thesis Aplicação geotécnica de resíduo de mineração em sistemas de cobertura final de aterros sanitários(2020-03-19) Gondim, Tiago Feitosa; Ingunza, Maria Del Pilar Durante; Freitas Neto, Osvaldo de; ; ; ; Santos Junior, Olavo Francisco dos; ; Severo, Ricardo Nascimento Flores;The use of mining residues within production chains, such as civil construction, is an important environmental solution for mining activities in Brazil. Researchers have shown that different types of mining residues can be incorporated into some types of geotechnical works, fulfilling the function of hydraulic barrier. In this scenario, the use of scheelite residue in environmental geotechnics works could be an environmentally sustainable solution for this material. This work aims to evaluate the technical viability of using two scheelita mining residues as a compacted coating with hydraulic barrier function in waste landfill covering systems. Physical characterization, compacting, hydraulic conductivity on rigid and flexible wall permeameters, XRF/XRD and SEM and erodibility tests were performed on four materials formed by mixing two residues generated during the scheelite processing at the Brejuí Mine in Currais Novos/RN. In the tests, samples were conformed by the two residues used, varying from the fine residue exclusively, and departing for variations of 25% by mass of the coarse residue content (F100, F75G25, F50G50 and F25G75). The obtained results demonstrate the technical viability of the intended use of the material. The F100 and F75G25 samples proved to be viable for the intended application (hydraulic barrier in landfill covering), meeting international normative requirements. The other composites (F50G50 and F25G75) could be applied for other purposes within a waste landfill: as regularization and/or protection layers. During the hydraulic conductivity tests, it was observed that, in the samples that contained a higher percentage of fine particles (< 0,075 mm), there was a progressive decrease in the permeability of the compacted material, from 1,76x10-6 to 2,18x10-8 m/s, but not necessarily a significant variation in the density or porosity, indicating that the incorporated fines filled the voids of the larger particles increasing the flow tortuosity. The decrease in permeability can be explained by morphological factors specific to the material used.Master Thesis Aplicação de concreto asfáltico a quente utilizando resíduos da construção e demolição de obras (RCD) em via urbana na cidade de Natal/RN(2019-03-25) Queiroz Neto, Manoel Lindolfo; Amorim, Enio Fernandes; França, Fagner Alexandre Nunes de; ; ; ; Silva, Moacir Guilhermino da; ; Conciani, Wilson;The construction industry is responsible for the high generation of solid waste that is discarded in nature, contributing to the degradation of the environment. On the other hand, the construction sector is one of the main components of the Brazilian economy and its productive chain brings together a set of activities that mobilize more than 12 million people, about 13% representing the workforce in the country (FIESP, 2017). At the global level, the building materials industry is expected to grow by two and a half times between 2010 and 2050 (UNEP, 2002). In Brazil, the construction sector is expected to double in size until the year 2022 (CEBEDS, 2009). It is noteworthy that it is crucial to take measures aimed at the management of solid waste through cultural and technological changes, aiming to meet the needs of a society increasingly enlightened and demanding in relation to the preservation of the environment. This work presents a proposal for the application of construction and demolition waste (RCD) as recycled aggregates in the manufacture of asphalt coating, as an alternative to the use of these materials. The work method employed consisted of the collection of residual material in the company TcPav, carrying out characterization tests in accordance with the standard standards in the area of paving in the national scope, besides DRX, FRX and dosage by the Marshall method. Then an experimental section was made using a market trace, adapted for use with RCD. In this trait was used recycled aggregate containing gravel 1 and sand replacing the same aggregate of the natural type in the coating layer. From the proposed experimental program it was observed that the residual aggregates had a good potential of their use in hot asphaltic coatings based on the analysis of the specimens under the volumetric parameters, the Marshall dosage and the experimental section. As for the experimental section, it was observed that in the initial months of monitoring a detachment of the ceramic aggregates present on its surface was observed. However, such detachment has not compromised to the point of damaging the coating, so that the asphalt pavement continues to perform satisfactorily the functionality for the vehicles which travel therethrough.Master Thesis Tijolos de solo-cimento produzidos com manipueira em substituição à água(2019-03-11) Souza, Jônatas Macêdo de; Acchar, Wilson; ; ; Cabral, Kleber Cavalcanti; ; Lucena, Luciana de Figueiredo Lopes; ; Silva, Vamberto Monteiro da;The construction industry is recognized as one of the largest consumers of natural resources on the planet. The number of researches aimed at reducing the impacts caused by the sector has grown considerably in recent years. The development of new construction materials, which contribute to reducing environmental impacts, satisfying current standards, has been debated and studied by researchers. One of these materials is the soil-cement brick which is considered to be ecological and presents a great potential of incorporation of residues of several industries that need studies for treatment and/or reuse, such as ceramic waste, rice husks, bottle waste PET, etc. An environmental liability that requires research to be reused is cassava water, an industrial byproduct (effluent), from the pressing of cassava in flour house, highly polluting, due to its toxicity and concentration of organic matter. Some authors have proposed alternative solutions for treatment or disposal of this waste, and the production of bricks is one of them. Thus, this study aimed to evaluate the physical, mechanical, and microstructural properties of solid bricks soil-cement produced with cassava instead of water. After characterization of the raw materials of the soil-cement formulations, 3 complete 2k factorial experimental designs with 3 replicates at the central point were elaborated to reduce the number of samples. The cement was used in the proportions 6%, 9%, and 12%, and the cassava wastewater 0%, 50% and 100% instead of water. Thus, 5 formulations were produced. The compressive strength tests were performed at 7, 28, and 49 days. The water absorption and modified durability tests were performed at 7 days. Subsequently, the microstructure of the bricks with 12% cement and 0% and 100% of cassava wastewater and 9% of cement and 50% of cassava wastewater was studied by means of X-ray diffraction and scanning electron microscopy (SEM). All formulations showed results of compressive strength above 1MPa. In the water absorption test, all the samples obtained results below 20%. And in the modified durability test, all compositions showed mass loss below 1%. In the X-ray diffraction tests the kaolinite, quartz, calcite, CASH (calcium aluminate silicate hydrated) and CSH (calcium silicate hydrated) phases were identified in all samples analyzed. In the SEM, it was possible to verify the soil particles and typical structures of the CSH. It is worth mentioning that the bricks produced with cassava wastewater presented similar results to those obtained in the formulations that did not use the waste. It is possible to conclude that the results demonstrate the technical feasibility of using cassava waste water instead of water in the production of soil-cement bricks for use in masonry without structural function.Master Thesis Emprego de geossintéticos na construção de telhados verdes: análise da capacidade de retenção de água(2016-03-18) Louzada, Thiago de Souza; França, Fagner Alexandre Nunes de; Scudelari, Ada Cristina; ; http://lattes.cnpq.br/6556306307432176; ; http://lattes.cnpq.br/6854485206744906; ; http://lattes.cnpq.br/4035912012748518; Santos, Helio Rodrigues dos; ; http://lattes.cnpq.br/9048384392428073; Araújo, Gregório Luís Silva; ; http://lattes.cnpq.br/6075465233665208Considering the current environmental situation in large cities, as well as the soil sealing, which is responsible for reducing the soil infiltration capacity, this study presents the green roofing technique as a feasible and compensatory alternative in controlling urban runoff. Besides, the green roofs, also known as living roofs, vegetated roofs or ecoroofs, provide advantages such as reduction of heat islands in urban centers, good thermal insulation in hot and cold climates, improve the air quality and others. Green roofs are relatively popular in Europe, especially in Germany, where there is a wide and growing use of the system. Geosynthetic materials may play na importante role in technical improvements, since they can be used with different functions such as waterproofing the base, protection against roots, filter, drain, water storage and stability of the substrate. The main objective of this research was to register the water retention capacity of different configurations of green roofs through small scale green roof modules and a rain simulator. Different geosynthetics materials were used as drainage layer. In addition, plane and inclined conditions were tested. Construction and operational aspects of the modules were also observed. As a result, it was confirmed that green roofs, even with substrate height of 4 cm, can retain considerable amount of water, which added to the delay in the beginning of the flow. They can be used as a compensatory measure in urban drainage systems. The retention rate from the module that there was geomat as drainage layer was between 47% (inclined) and 65% (plane). Such water retention rate was obtained for precipitation intensities equal to 44 mm/h and 42 mm/h, respectively, subjected to 20-minute long rain simulation. This module presented a delay in the flow beginning equal to 9 minutes (inclined) and 15 minutes (plane). Thus, the slope of the green roof has shown a great influence in both the retention rate and the time necessary to start the flow of rainwater. The module in which only a geotextile nonwoven separates the substrate from the waterproofing layer presented excellent water retention capacity, yet a lower drainage capabiltiy. It means that the intensity of precipitation was higher than the flow rate supported by the system, causing overflowing. In the module with geomat as drainage layer, the system worked perfectly, showing no overflow at any occasion. Regarding the use of geosynthetics, it was possible to mount the modules without any problems, in a simple and quickly manner, requiring only a few hours to assemble the materials and vegetation.Master Thesis Estudo de concretos autoadensáveis com reduzidos teores de cimento e elevados teores de adições minerais(2016-05-06) Medeiros, Fernanda Karolline de; Anjos, Marcos Alyssandro Soares dos; Almeida, Maria das Vitorias Vieira; ; ; ; Nóbrega, Andreza Kelly Costa; ; Barbosa, Normando Perazzo;The concrete production process generates a significant environmental impact as one of the largest consumers of raw materials, like sand, stone and water. However, the greatest impact is caused by the production of Portland cement, an essential material to the concrete. Materials such as sugarcane bagasse ashes (RBC), silica from rice husk (PCA), metakaolin (MK) and silica fume, are mineral additions that play an important role in resistance and durability properties, when used in combination with Portland cement and, under certain conditions, can perfectly replace high cement content in mixtures, given to them in addition to the known benefits that cement reduction entails, like significant increase in durability. The use of self-compacting concrete (SCC) has grown significantly by its high fluidity characteristics and cohesiveness and the possibility of forming in situ without vibration, forming a fault and void-free product which has also flowability by its own weight completely filling the molds and reaching compaction even in heavily armed structures. Based on these, this study aimed to evaluate the rheological, physical, mechanical and durability properties of self-compacting eco-concrete with the high percentage incorporation of sugarcane biomass ashes, silica from rice husk and metakaolin. Based on these, this study evaluated the rheological properties, physical, mechanical and durability freight to attack by chloride ions of self-compacting ecoconcrete with the incorporation of high content of ash biomass sugarcane, rice husk silica and metakaolin. For this, a self-compacting concrete with conventional materials without mineral admixtures for use as a reference and four concrete incorporating 40% and 50% additions were analyzed using gray bagasse from sugarcane, pozzolan rice husk and metakaolin. The results showed that the resulting synergy of developed mixtures revealed mechanical and durability performance, freight to attack by chloride ions, above the reference SCC. When compared to the reference concrete, concrete with additions showed an increase of up to 13.4% of the compressive strength at 28 days and reducing to 87% the penetration of chloride ions to 91 days. The results of the study also showed that incorporating high volumes of mineral additions in the SCC causes a reduction of the environmental impact generated by the anthropogenic emissions of CO2, the energy consumed and the consumption of natural materials, thus confirming the relevance of the research. It is possible to produce self-compacting concrete with promising performances, using high RBC levels, PCA and MK, with a significant reduction in cement consumption to levels of about 220 kg / m3, thus contributing to the sustainability of the construction industry, minimizing energy released and compression.Master Thesis Avaliação da potencialidade de incorporação de um lodo de uma indústria de produtos de limpeza como adição mineral em concretos de cimento Portland(Universidade Federal do Rio Grande do Norte, 2015-11-24) Silva, José Daniel Jales; Ingunza, Maria Del Pilar Durante; Albuquerque, Liana Filgueira; ; http://lattes.cnpq.br/8259087042517666; ; http://lattes.cnpq.br/1925954531585024; ; http://lattes.cnpq.br/1695824226208694; Nobrega, Andreza Kelly Costa; ; http://lattes.cnpq.br/9418395015529669; Camarini, Gladis; ; http://lattes.cnpq.br/8939257949743478The generation of industrial wastes has been increased more and more in recent decades, motivating studies about a correct sustainable allocation and that also represents advantages for their generators. In this context, are included two companies of cleaning products niche, located in São José do Mipibu/RN, that produces industrial sludge at a sewage treatment plant, and that is the main approach of this research. Given this, it was studied the incorporation potentiality of this sludge as a mineral addition in cement matrix for concrete production due it high capacity of wastes immobilization inside this material, which are subsequently used in the company for making precast articles. Were added different sludge concentrations (5, 10, 15 and 20%) in a common trait (1: 2: 3), and evaluated their techniques and microstructural implications via workability test in fresh state and compressive strength, full porosity and scanning electron microscopy (SEM) in the hardened state. The results demonstrated the feasibility of the process both from a technical and environmental view as economical. All concretes produced with residue showed an increase of workability given the nature of the waste that had surfactants substances capable of adsorbing tiny particles of air into the batter. However, for all concentrations were obtained lower compressive resistances than standard concrete, with a reduction of 39% for samples with 20% of sludge. This are attributed mainly to an increase of porosity in the transition zone of these material, resulting from increased formation of ettringite at the detriment to the formation of other compounds, but which still allows the use of these for the manufacture of concrete articles with non-structural nature, such as precast floor. In addition, the water absorption and void ratio increased slightly for all samples, except the concrete with 20% of waste that has a reduction for the last parameter. Given this context, the recommended maximum level is 20%, constituting a significant proportion and able to allocate sustainably all waste generated in the industry.