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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
451

Influência do agregado graúdo reciclado de resíduos da construção predial nas propriedades do concreto fresco e endurecido

NUNES, Wesley Carlos 04 October 2007 (has links)
Made available in DSpace on 2014-07-29T15:03:37Z (GMT). No. of bitstreams: 1 Dissertacao Wesley Carlos Nunes.pdf: 7932394 bytes, checksum: b486f88aa078b83264c74d2720002782 (MD5) Previous issue date: 2007-10-04 / Recycling waste materials is an efficient way to hinder environmental, social and economic impacts of the civil construction industry. This dissertation aimed at verifying the behavior of different concretes made of coarse recycled aggregate (AGR), mineral fractions collected from the waste (RCD) of a high- rise apartment building (multiple floor building). The RCD has been selectively collected at the building construction site and processed by a jaw crusher. The study focused on the effects of gradual replacements of coarse natural aggregate (AGN) by AGR where the fundamental properties of the fresh and hardened concretes are concerned. The experiment involved the production of three dry aggregate/ceme nt ratios: (3,5 / 1), (5 / 1) and (6,5 / 1) for each concrete family (zero%, 25%, 50%, 75% and 100% replacement contents of AGN by AGR), and thus 15 different concrete mix proportions were manufactured. Workability, entrapped air, and density were the variables analyzed in the fresh concretes. Furthermore, water absorption, density, total pores volume, compressive strength, splitting-tensile strength, and initial-tangent modulus were the properties studied in hardened concretes. The strengths of concretes with AGR contents are lower than those of corresponding reference concretes (zero% of replacement content of AGN by AGR). However, reductions in the cement content in mixtures of the concretes produced with AGR showed compressive and splitting-tensile strengths values nearer to those of the reference concrete family. The experiment allows for the conclusion that concretes produced from AGR of RCD can be used for several purposes in civil construction, if the management of concrete mix proportions and the control of quality are performed under the liability of capable and qualified professionals. / Para minimização significativa dos impactos sócio-ambientais e econômicos provocados com o entulho gerado pela indústria da construção civil, a reciclagem destes resíduos apresenta-se como caminho alternativo e eficiente. Mediante esta perspectiva, buscou-se nesta dissertação verificar o comportamento de concretos produzidos com agregado graúdo reciclado (AGR), proveniente das frações minerais contidas no entulho (RCD) de um edifício de múltiplos pavimentos, a partir de coleta seletiva na obra e posterior beneficiamento do material em sistema de britagem. Foram estudados os efeitos de substituições gradativas do agregado graúdo natural (AGN) por AGR de RCD, nas propriedades fundamentais dos concretos, tanto no estado fresco quanto no estado endurecido. Para o desenvolvimento experimental foram produzidos concretos em três proporções de dosagem: (1 : 3,5), (1 : 5,0) e (1 : 6,5) (cimento : agregados secos), e cinco teores de substituição (0%, 25%, 50%, 75% e 100%) do AGN por AGR, totalizando, desde modo, 15 proporções de dosagem estudadas. A trabalhabilidade, teor de ar aprisionado e massa específica foram as propriedades estudadas nos concretos em estado fresco. As propriedades avaliadas no estado endurecido dos concretos foram absorção de água, massa específica, índice de vazios, resistência à compressão axial, resistência à tração por compressão diametral e módulo de deformação. As resistências dos concretos produzidos com teores de AGR apresentaram-se inferiores aos correspondentes concretos de referência 0% de teor de substituição do AGN por AGR. Entretanto, na proporção em que se reduziu o consumo de cimento nas dosagens, os concretos produzidos com AGR apresentaram valores de resistências à compressão e à tração mais próximos aos resultados aferidos para os concretos de referência. Os experimentos conduziram a concluir que, tanto do ponto de vista técnico quanto econômico, os concretos produzidos com AGR de RCD podem ser normalmente utilizados na construção civil, desde que as dosagens das misturas e o controle de qualidade destes concretos sejam realizados sob responsabilidade de profissionais comprovadamente habilitados e especializados.
452

Geovisualização analítica: desenvolvimento de um protótipo de um sistema analítico de informações para a gestão da coleta seletiva de resíduos urbanos recicláveis. / Analytical geovisualization: development of a prototype of an analytical information system for the management of the selective collection of recycled urban solid waste.

Carlos Enrique Hernández Simões 16 April 2010 (has links)
Os resíduos urbanos descartados de forma irregular constituem um problema sério, principalmente nas grandes cidades, causando entupimento de bueiros e drenagem com conseqüentes inundações, sujeira e transmissão de doenças tais como leptospirose e dengue além de ser um estorvo para o trânsito e acarretarem gastos para a Prefeitura. Por outro lado, reciclar este material é uma fonte de receitas e um gerador de empregos. A Geovisualização Analítica pode ser de grande auxílio para a análise desse problema complexo e para a tomada de decisão. Com essa motivação, a presente dissertação procura fornecer uma visão geral sobre o estado da arte quanto a conceitos e pesquisas em Geovisualização (GVis) e Processamento Analítico (OLAP e SOLAP). Apresenta também processos, metodologias e tecnologias que foram utilizadas no desenvolvimento de um protótipo de um sistema analítico de informações aplicado à área de gestão da coleta seletiva de resíduos sólidos recicláveis em ambiente urbano. Este protótipo, efetivamente implantado, combinou navegação e consulta para recuperar informações através de seleções espaciais e alfanuméricas. Através de exemplos foi mostrado que este tipo de solução auxilia gestores nos processos de exploração, análise e tomada de decisão. / Domestic waste illegally disposed constitute a serious problem, especially in large cities, causing clogging of drains and drainage with subsequent flooding, dirt and transmission of diseases such as leptospirosis and dengue as well as being a hindrance to traffic and would entail city hall costs. Moreover, recycle this material is a source of revenue and a generator of jobs. The Analytical Geovisualization can be of great help in the analysis of this complex problem and the decision-making. With this motivation, this paper seeks to provide an overview of the state of the art as the concepts and research in Geovisualization (GVis) and Analytical Processing (OLAP and SOLAP). It also presents processes, methodologies and technologies that were used in developing a prototype of an analytical system applied to the area of selective collection information management of recyclable solid waste in urban environments. This prototype, effectively deployed, combined navigation and query to retrieve information through spatial and alphanumeric selections. Through examples it was shown that this type of solution helps managers in operating procedures, analysis and decision making.
453

Recyklované kamenivo do pozemních komunikací / Recycled aggregate to pavement constructions of roads

Antošová, Klára January 2015 (has links)
The diploma thesis deals with using of recycled aggregate of concrete for base layers of pavement. The work is divided into practical and theoretical part. The theoretical part deals with basic concepts of construction and demolition waste, production, development and management of this waste in the Czech Republic. It also focuses on the principle of recycling and the use of recycled concrete in the Czech Republic and abroad. The practical part of the thesis deals with laboratory testing and assessment of recycled aggregates in bound, unbound and grouted courses layers of the base layers of roads.
454

Vývoj nové technologie pískového pórobetonu s využitím druhotných surovin / Development of new technology of sand autoclaved aerated concrete with using of secondary raw materials

Ondříčková, Pavlína January 2018 (has links)
Autoclaved sand aerated concrete is a modern building material with high thermal insulation properties. Only sand is used as the primary silicate component of aerated concrete in the Czech Republic. For the more favourable economic and ecological properties of aerated concrete, the use of secondary raw materials is used in this work. The secondary raw materials examined included fluidized bed and fly ash, slag and glass recycled. The aerated concrete composite with secondary admixtures was developed under hydrothermal conditions of a laboratory autoclave for 7 and 12 hours at 190°C. From the secondary raw materials tested, a 10% glass recycler additive yielded the highest strength. Other additives that have a positive effect on mechanical properties include SAKO and Oslavany. From the results of the work it is evident that the use of secondary raw materials increases the strength, improves the rheology of the mixture and supports the formation of tobermorite.
455

Charakteristické vlastnosti směsných recyklátů pro spodní stavbu pozemních komunikací / Characteristics of mixed building recyclates for subgrade og roads

Junek, Lumír Unknown Date (has links)
The work deals with the use of mixed construction recycled material for earth bodies of roads. The theoretical part describes the production, usability and economic evaluation of recycled building materials against common natural materials. It then describes the necessary laboratory tests that examine its properties for the use of these materials in roads. In the last chapter, the work deals with foreign experience with the use of mixed construction recyclates for transport construction. The practical part examines the properties of the given recyclates for their use in the core using tests of soil freezing rate, California bearing ratio and immediate bearing index.
456

Směsný recyklát do podloží vozovek pozemních komunikací / Waste building material to subgrade pavement

Masař, Daniel Unknown Date (has links)
The theoretical part of the diploma thesis searches the production of Construction and demolition waste and their subsequent transformation into the final recyclate and its possible use in roads. Attention is focused on the use of mixed recycled material into subgrade of the pavement and the characteristics of tests that must be performed before its used to the road. The next chapters pai attention to the problematic properties of recyclates, foreign experience with the use of mixed recyclate in Construction and the possibilities of its development. The practical part verifies the suitability of mixed recycled material into subgrade of the pavement using laboratory tests. The tests are performer on individual mixtures of mixed recycled material with cement, blast furnace slag or cement dust in various percentages. The results are then compared and it is evaluated which mixtures show the best properties. Part of the practical part is also the economic evaluation of these mixtures against commonly used materials.
457

Změna trvanlivosti betonu z recyklovaného betonu variantní adicí silikátových příměsí / Change in the durability of concrete made of recycled concrete by alternative addition of ceramic admixtures

Stavař, Tomáš January 2013 (has links)
The master thesis dealing with problematic about durability of concrete, with use of recycled concrete and addition of silica additions. Predominant for resistance of concrete constructions is surface layer, through which aggressive gasses and liquids penetrate from surrounding environment. The most important indicator of concrete durability is ability of surface layer transmissions of aggressive substants. In experimental part will be defined the actual state of surface layer by normal testing methods. The transmissions of surface layer will be tested on concrete cubes. Tests for transmissions of air (method TORRENT), of water (method ISAT), of acid gases (dept of carbonation by quick test in 98% CO2) will be carried out and also strength tests. Assessment of positive or negative influence of additions and amount of cement on durability and mechanical properties of concrete will be discussed in conclusion.
458

Stavební recykláty pro stmelené směsi vozovek / The building waste for bound mixtures of the pavements

Pokluda, Radim January 2013 (has links)
In the theoretical part of the thesis are generally characterized hydraulically bound mixtures, their types, classification systems, manufacturing technology and the laying. There are also described experiences from abroad with the use secondary and recycled materials in hydraulically bound mixtures. The practical part deals with the experimental verification of the possibility of the use of secondary materials in hydraulically bound mixtures in construction of road infrastructure. In road laboratory Institute of road structures Brno university of technology was the five proposed mixtures, an assessment of their parameters with regard to the possibility of using these mixtures in the road sub-base layers. The work is also aimed at comparison of results elasticity modules reached laboratory testing and experimental measurements on road polygon.
459

Nestmelené a stmelené směsi z betonového recyklátu dálnice D1 / Unbound and bound mixtures from recycled concrete of highway D1

Mikulíková, Petra January 2014 (has links)
The work is divided into two parts. The first part deals with the description of unbound and bound base layers and their comparison. Furthermore is presented the description of the recycled concrete, its properties, production, improvement and issues. International experiences with recycled concrete technology are described as well. The practical part is focused on laboratory testing of concrete recycled material taken from the highway D1. The aim of this part is to determine whether the concrete can be recycled back into unbound or bound base layers and concrete casing.
460

Vliv použití R - materiálu na funkční vlastnosti asfaltových směsí / Influence of usage of recycled material on asphalt mixtures functional properties

Šperka, Pavel January 2015 (has links)
Diploma thesis deals with the topic of using recycled material in the production of asphalt mixtures. In the theoretical part the methods of recycling flexible pavement are described and as well as ways in which recycled material is added to asphalt mixtures produced by the stationary hot mix plant. The thesis also deals with the current state of recycled material use in the Czech Republic and the reasons for its possible greater use. The practical part of the thesis studies the effect of using the amount of 20% recycled material to asphalt mixtures of asphalt concrete for wearing course ACO11+, on selected functional properties of these mixtures. It is also investigates the influence of bitumen binder contained in the recycled material, on the final properties in manufactured asphalt mixtures. An integral part of this thesis is a description of all methods that were used during the processing of the practical part. In the end of this thesis there are some results of findings about adding recycled material into asphalt mixtures.

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