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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.
41

Development of Concrete Mixtures Based Entirely on Construction and Demolition Waste and Assessment of Parameters Influencing the Compressive Strength

Yildirim, Gurkan, Ozcelikci, E., Alhawat, Musab M., Ashour, Ashraf 22 March 2023 (has links)
Yes / Demolition and reconstruction of degrading structures alongside with the repetitive repair, maintenance, and renovation applications create significant amounts of construction and demolition waste (CDW), which needs proper tackling. The main emphasis of this study has therefore been placed on the development of concrete mixtures with components (i.e., aggregates and binder) coming entirely from CDW. As the binding phase, powdered CDW-based masonry units, concrete and glass were used collectively as precursors to obtain geopolymer binders, which were then incorporated with CDW-based fine and coarse concrete aggregates. Together with the entirely CDW-based concretes, designs were also proposed for companion mixtures with mainstream precursors (e.g., fly ash and slag) occupying some part of the CDW-based precursor combination. Sodium hydroxide (NaOH), sodium silicate (Na2SiO3) and calcium hydroxide (Ca[OH]2) were used at various concentrations and combinations as the alkaline activators. Several factors that have impact on the compressive strength results of concrete mixtures, such as mainstream precursor replacement rate, al-kaline molar concentrations, aggregate-to-binder ratios and curing conditions, were considered and these were also backed by the micro-structural analyses. Our results showed that through proper optimiza-tion of the design factors, it is possible to manufacture concrete mix-tures entirely out of CDW with compressive strength results able to reach up to 40 MPa under ambient curing. Current research is believed to be very likely to promote more innovative and up-to-date techniques to upcycle CDW, which are mostly downcycled through basic practices of road base/sub-base filling, encouraging further research and increas-ing the awareness in CDW issue.
42

Vliv umístění stavby na cenu a náklady stavebního objektu / The influence of the location of buildings on price and cost of a building

Petr, Lubomír January 2017 (has links)
The thesis deals with the influence of the location of buildings on the price and the cost of a building. In the first theoretical part it deals with brownfields, redevelopment of geological environment and construction and demolition waste. In this passage the various concepts, their division, the legislative side of things and generally their problems are explained. The second part is practical, it analyzes the cost associated with the revitalization of abandoned buildings for the possibility of reuse of land. For these purposes the representative brownfield is created and it is set in different environment. In conclusion all important findings are summarized.
43

Local Economic Development Agencies' Support for Construction and Demolition Recycling

Patterson, Lynn M. 06 April 2007 (has links)
The construction and demolition (C and D) recycling industry creates economic opportunity through business activity; promotes equity through workforce training and partnerships; and helps to conserve natural resources through the reuse, remanufacturing, and recycling of C and D debris. While C and D recycling satisfies traditional local economic development goals, it also addresses broader goals of progressive, and sustainable local economic development. The general planning literature shows an increasing interest in sustainability; however, there have been fewer studies on sustainable local economic development initiatives. This research examines the current state of local economic development agency support for the C and D recycling industry as an economic development strategy. In doing so, the dissertation assembles the array of activities local economic development agencies used to support the industry; identifies distinguishing policy or contextual characteristics of agencies that actively supported the industry from those that did not; and assesses whether the agencies support for C and D recycling fit within the rational planning model. Using data from a national survey of local economic development agencies, the study categorizes the local economic development tools used to support the industry. Results show that a combination of traditional, progressive, and sustainable local economic development tools are adapted and newly created to satisfy the specific needs of this specialized industry. Multiple discriminant analyses identify key characteristics of the agencies that support C and D recycling. These characteristics include previous support for the general recycling industry, the presence and support of environmental enterprise zones and eco-industrial parks, and knowledge of local landfill capacity issues. Overall, the agencies that actively supported C and D recycling engage in activities associated with sustainable local economic development. The descriptive and statistical analyses are combined with the surveys qualitative responses to determine that local economic development agencies do not operate under a strict interpretation of the comprehensive rational planning model in their support of C and D recycling. Instead, local economic development agencies use modified rational and reactive planning strategies in their support of the industry. The study concludes with policy recommendations to increase local economic development agency support for C and D recycling.
44

Análise da disposição final dos resíduos de construção e demolição na cidade de João Pessoa

Caldas, Ana Helena Mousinho 16 March 2016 (has links)
Submitted by Maike Costa (maiksebas@gmail.com) on 2017-10-03T11:33:15Z No. of bitstreams: 1 arquivototal.pdf: 3170454 bytes, checksum: 4df0811997519669118a21ed7a252651 (MD5) / Made available in DSpace on 2017-10-03T11:33:15Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3170454 bytes, checksum: 4df0811997519669118a21ed7a252651 (MD5) Previous issue date: 2016-03-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Waste resulting from the construction industry have a significant negative environmental impact, thus being a major problem for the construction industry and the regulatory agencies. The minimization of this waste can occur if they are properly managed from its generation to its final disposal, contributing to the reduction of environmental degradation. This research presents the results of the verification of the performance of the components of the RCD flow (generator - transporter - receiver for final disposal) regarding establishing legislation in the João Pessoa city. The aim of this study is to verify the compliance percentage (level of service) the final disposal stage of RCD flow in relation to the provisions of the legislation. The study presents the adherence percentage for the two companies officially responsible for the final disposal of this region, namely the USIBEN (RCD processing plant) which showed 79% of adherence and the Landfill Metropolitan which showed 63% adherence. The results show deviations in the treatment of RCD in relation to what is provided in legislation, especially to waste class D, which are considered dangerous, as well as other points that can and should be improved. / Os resíduos resultantes da indústria da construção civil têm um impacto ambiental negativo relevante, sendo assim um grande problema para o setor da construção civil e para os órgãos fiscalizadores. A minimização destes resíduos pode ocorrer se os mesmos forem corretamente gerenciados desde sua geração até sua disposição final, contribuindo para a diminuição da degradação do meio ambiente. Esta pesquisa apresenta os resultados da verificação da atuação dos componentes do fluxo de RCD (gerador – transportador – receptor para disposição final) em relação ao disposto na legislação na cidade de João Pessoa. O objetivo geral deste trabalho é verificar o percentual de aderência (nível de atendimento) da etapa de disposição final do fluxo de RCD em relação ao disposto na legislação. O estudo apresenta o percentual de aderência para as duas empresas oficialmente responsáveis pela disposição final desta região, qual seja, a USIBEN (usina de beneficiamento de RCD) que apresentou 79% de aderência e o Aterro Metropolitano que apresentou 63% de aderência. Os resultados demonstram desvios no tratamento de RCD em relação ao que está disposto na legislação, especialmente para com os resíduos classe D, que são considerados perigosos, além de outros pontos que podem e devem ser melhorados.
45

Recycling in the demolition industry - a case study of Destroy AB

Fredriksson, Peter, Tafreshi, Simon January 2016 (has links)
Landfill and mixed wastes are more expensive to dispose of than sorted wastes, and also decrease the possibilities for recycling of wastes. This thesis aimed towards determining what the potential benefits could be with leasing a sorting site and whether or not Destroy RC AB should introduce a sorting site to their business from a primarily economic perspective. The materials included in landfill and mixed wastes were determined and were prioritized differently depending on the economic and environmental benefit from sorting and recycling each material. If a sorting site was introduced to Destroy’s network of processes, unsorted waste types would be sent to the sorting site from demolition sites instead of to landfill and recycling sites. Scenarios with different variations of amounts of wastes at the sorting site, compositions of wastes, truck types used for transports, and sorting speeds were studied and used for total cost analyses
46

Deconstructing Elevated Expressways: An Evaluation of the Proposal to Remove the Interstate 10 Claiborne Avenue Expressway in New Orleans, Louisiana

Henry, Kim Tucker 20 December 2009 (has links)
With the passage of the Federal Aid Highway Act of 1956, the interstate system included an elevated segment of Interstate 10 constructed over Claiborne Avenue in New Orleans, Louisiana. The I-10 Claiborne Expressway provided access to downtown by destroying a tree-lined boulevard and contributing to the decline of an African American neighborhood. In 2005, after hurricane Katrina, several community-based plans proposed that the elevated I-10 Claiborne Expressway be removed. This thesis compares the removal proposals to the decision making processes of five case cities that have removed expressways. Necessary conditions were applied to all expressway removal cases. Currently, the I-10 Claiborne Expressway decision making process lacks defined structural integrity and safety concerns, a reduction in the value of freeways by power brokers, documented support of the business community and “selling” of idea by a public agency. These conditions were necessary to the decision to remove expressways in all case cities.
47

Twice Displaced: Katrina and the Redevelopment of the Magnolia

Garza, Gabriella A 18 December 2015 (has links)
Where and how to house the urban poor remains a controversial issue. Public housing residents are particularly vulnerable. Issues of race, class and gender intersect in their lives. Public-private partnerships in urban redevelopment projects and a focus on issues that arise from concentrated poverty gave rise to HOPE VI policy aimed at deconcentrating poverty via public housing demolition and redevelopment. In New Orleans, the effects of Hurricane Katrina further complicate this contested process. The purpose of this case study is to understand how residents experienced and framed the process of displacement brought on by disaster and the redevelopment of the Magnolia projects, comparing those who returned to the revitalized project to those who did not. The data I collected are 4 semi-structured interviews and one focus group with residents, 56 newspaper articles, and 60 photos. Doing so uncovered nuanced resident narratives often left out of public housing redevelopment decisions.
48

Metodologia de avaliação do potencial de reciclagem de resíduos / Methodology to evaluate the recycling potential of waste products

Zordan, Sérgio Eduardo 30 September 2003 (has links)
Esta pesquisa propõe uma metodologia para avaliar o potencial de reciclagem de resíduos e indicar as aplicações mais sustentáveis, considerando aspectos econômicos, de mercado, ambientais e de risco à saúde humana. A idéia central é avaliar o uso do resíduo baseado em suas características e propriedades físico-químicas e, a partir disso, identificar áreas potenciais que possam absorvê-lo da forma mais sustentável possível. A avaliação da aplicabilidade foi realizada com base em requisitos identificados por especialistas de diversas áreas. A metodologia foi testada para avaliar o potencial de reciclagem dos resíduos de tratamento de esgoto e dos resíduos de construção e demolição (RCD). / This research suggests a methodology to evaluate the recycling potential of waste products and to indicate the most sustainable applications regarding economical, market, environmental and hazard to human health aspects. The main idea is to evaluate the use of the waste based on its physico-chemical characteristics and properties, and then, to identify potential areas to absorb them, through sustainable processes. The evaluation of the applicability has been based on requirements identified by specialists from several areas. The methodology has been applied to evaluate the recycling potential of sewage sludge wastes and construction and demolition wastes (CDW).
49

Uso de finos de resíduos de construção e demolição em concreto autoadensável

Santos, Iago Lopes dos January 2018 (has links)
O concreto autoadensável (CAA) é um concreto especial com a capacidade de fluir e preencher completamente todos os espaços das fôrmas pela ação de seu peso próprio, sem que haja ocorrência de bloqueio e segregação da mistura. Contudo, para alcançar essas características, normalmente esse concreto é dosado com um maior teor de materiais finos e/ou com aditivo modificador de viscosidade. Os agregados provenientes de Resíduos de Construção e Demolição (RCD) já estão sendo utilizados na produção de concretos, porém o uso dos materiais finos de agregados reciclados não é recomendado para a produção de concretos convencionais. Entretanto, acredita-se que em CAA esses materiais finos podem ser uma oportunidade interessante, tanto para a questão da reutilização desses resíduos, conseguindo uma destinação nobre para esses materiais com baixa demanda no mercado, como na manutenção das propriedades deste concreto, sendo os principais agentes do controle de segregação. Desta forma, o presente trabalho consistiu em estudar a influência da utilização de finos de RCD (concretos, argamassas e tijolos cerâmicos), separadamente, em substituição parcial ao agregado miúdo natural, nas principais propriedades do concreto autoadensável no estado fresco (fluidez, habilidade passante e resistência à segregação) e no estado endurecido (resistência à compressão e módulo de elasticidade), bem como avaliar seu desempenho quanto à durabilidade (absorção de água e penetração de íons cloretos). Os resultados demostraram perda de fluidez e boa coesão nos concretos autoadensáveis que empregaram agregados reciclados. No entanto, ainda conferem boas características de autoadensabilidade, atendendo as condições normativas para uso em estruturas correntes de engenharia. No que tange às propriedades mecânicas, foi observado aumento de resistência à compressão e decréscimo do módulo de resistência para concretos com finos de RCD. No quesito de durabilidade, os concretos com agregados reciclados apresentaram valores mais elevados para absorção de água por capilaridade e penetração de íons cloretos em comparação aos concretos de referência. / Self-compacting concrete (SCC) is a special concrete with the ability to flow into and completely fill all spaces within the formworks only by the action of their own weight, without blocking and segregation of the mixture. However, to achieve these characteristics, normally this concrete needs to be mixed with more content of fine materials and/or viscosity modifiers additives. The aggregates from Construction and Demolition Wastes (CDW) are used for concrete production, but the use of fine recycled aggregate is not recommended for the production of conventional concrete. Although, it is believed that in SCC these fine aggregates can be an interesting opportunity for the reuse of these wastes, achieving a noble destination for these materials with low demand in the market, as for the maintenance of the properties of this concrete, being the main agents of segregation control. So, the present research consisted in studying the influence of the use of CDW fines aggregates (concretes, mortars and ceramic bricks, separately) to replace the natural sand in the main properties of the self-compacting concrete in the fresh state (flowability, passing ability and segregation resistance) and in the hardened state (compressive strength and modulus of elasticity), as well as to evaluate its performance in terms of durability (water absorption and chloride penetration). The study results showed loss of flowability and increased cohesion in the self-compacting concretes that used recycled aggregates. However, they still confer good characteristics for self-compacting concrete, taking into account the normative conditions for using current engineering structures. With respect to the mechanical properties, it was observed an increase of compressive strength and decrease of the modulus of elasticity for concrete with CDW fines aggregates. In terms of durability, concretes with recycled aggregates presented higher values for capillarity water absorption and penetration of chloride ions compared to the references concretes.
50

Caracterização tecnológica de resíduos de construção e demolição. / Technological characterization of construction and demolition waste.

Ulsen, Carina 22 August 2006 (has links)
Os resíduos de construção e demolição (RCD) representam cerca de 50% de todo o resíduo sólido gerado, sendo que cerca de 90% deste é de origem mineral e pode ser reciclado através de processos de beneficiamento mineral. Para se atingir a reciclagem massiva torna-se imperativo o desenvolvimento de novos mercados e melhorias de usina capazes de tornar o resíduo uma matéria prima de qualidade adequada. Dessa forma a caracterização tecnológica é imprescindível para obtenção de informações fundamentais sobre o processo de beneficiamento e as especificações para os produtos. O programa experimental foi desenvolvido em três amostras de RCD britados de duas usinas de reciclagem do Estado de São Paulo, Itaquera cinza (IT-C), Itaquera vermelho (IT-V), Vinhedo vermelho (VI-V). As atividades desenvolvidas foram: amostragem, cominuição, determinação das composições químicas e mineralógicas por faixa granulométrica, determinação de propriedades físicas relevantes para reciclagem de RCD como agregados para uso em concreto, determinação das curvas de separabilidade por densidade e análise de sua composição química e mineralógica e estudos microscópicos para avaliação do teor de aglomerantes por faixa densitária. Os resultados de análises químicas mostram que as composições químicas das três amostras são semelhantes; os teores variam com a granulometria, com marcantes diferenças na fração mais fina. A composição mineralógica predominante é de silicatos, provenientes de agregados e rochas naturais, cerâmicas e aglomerantes, com menores teores de alumina e óxido de cálcio; a perda ao fogo está diretamente relacionada ao teor de aglomerantes, uma vez que representa a água combinada e o gás carbônico presente. A separação do RCD em classes de densidade permitiu identificar que os produtos obtidos apresentam composições diferentes e pode ser empregada para se obter agregados de melhor qualidade e, portanto, para aplicações mais nobres, uma vez que se verifica que cerca de 80% em massa dos resíduos possuem densidades superiores a 2,2 g/cm3 com qualidades físicas adequadas para uso em concreto estrutural. Adicionalmente, a massa específica aparente e absorção de água estão diretamente relacionadas com os intervalos de densidade. O teor de aglomerantes aumenta significativamente para os produtos de menor densidade, sendo que as partículas cerâmicas estão isentas de pasta de cimento endurecida e cal. / Construction and demolition waste (CDW) represents around 50% of the total solid waste and are essentially constituted by mineral fraction (>90%); therefore it?s possible to recycle it through mineral processing techniques. The development of different uses and the improvement of the typical technologies applied to CDW recycling are essential to achieve a satisfactory level of recycling. Applied mineralogy tools are fundamental to characterize the studied raw material and support the mineral processing in order to obtain products according to its specifications. This research was carried out in three crushed samples from two different plants close to Sao Paulo; they were named according to its classification: grey Itaquera (IT-C), red Itaquera (IT-V) and red Vinhedo (VI-V). The method involved basically sampling, crushing, characterization of the relevant physical properties for a concrete recycled aggregate approach, evaluation of the specific gravity separability curves and chemical and mineralogical analyses for each grain size fraction and gravity classes, and so microscope analyses to verify the binder contents. The results show that the chemical composition of the three samples is very similar, the grades change according to the grain size fractions, specially for the finest fraction. The mineral composition is also quite akin, it is mostly represented by silicates (mainly aggregates and natural rocks), ceramics and binder; minor amounts of Al2O3 and CaO were also detected. The loss of ignition is directly related to the binder and clay minerals (basically OH and CO2). Specific gravity classes are very different regarding their chemical, mineralogical and physical properties, despite their similarity among the samples. Thus the specific gravity separation is more effective to classify the recycled CD debris than its color and could be applied to obtain high quality recycled aggregates, while a significant amount (80%) is recovered above 2.2 g/cm3 and may be used as high strength concrete aggregates. In addition, the physical properties, like specific gravity and water absorption are strictly related to the specific gravity classes.

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