938 resultados para Construction and demolition waste


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The purpose of this research is to identify and assess the opportunities and challenges of implementing a Site Waste Management Plan (SWMP) on projects irrespective of size. In the UK, construction and demolition waste accounts for a third of all UK waste. There are a number of factors that influence the implementation of SWMPs. In order to identify and analyse these factors, 4 unstructured interviews were carried out and a sample of 56 participants completed a questionnaire survey. The scope of the study was limited to UK
construction industry professionals. The analysis revealed that more needs to be done if the industry is to meet government targets of reduction in construction related waste going to landfill. In addition, although SWMP may not yet be legally required on all construction projects, clients and contractors need to realise
the benefits to cut costs and implement best practice by adopting a SWMP. The benefits of implementing a SWMP will not only help to achieve this but also gain significant cost savings on projects and is also extremely beneficial to the environment. This study presents evidence that contractors need to do more to reduce waste and draws a clear link between waste reduction and the implementation of SWMPs. The findings are useful in the ongoing efforts to encourage the industry to find smarter, more efficient and less
damaging ways to operate

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The purpose of this work is to find a methodology in order to make possible the recycling of fines (0 - 4 mm) in the Construction and Demolition Waste (CDW) process. At the moment this fraction is a not desired by-product: it has high contaminant content, it has to be separated from the coarse fraction, because of its high water absorption which can affect the properties of the concrete. In fact, in some countries the use of fines recycled aggregates is highly restricted or even banned. This work is placed inside the European project C2CA (from Concrete to Cement and Clean Aggregates) and it has been held in the Faculty of Civil Engineering and Geosciences of the Technical University of Delft, in particular, in the laboratory of Resources And Recycling. This research proposes some procedures in order to close the loop of the entire recycling process. After the classification done by ADR (Advanced Dry Recovery) the two fractions "airknife" and "rotor" (that together constitute the fraction 0 - 4 mm) are inserted in a new machine that works at high temperatures. The temperatures analysed in this research are 600 °C and 750 °C, cause at that temperature it is supposed that the cement bounds become very weak. The final goal is "to clean" the coarse fraction (0,250 - 4 mm) from the cement still attached to the sand and try to concentrate the cement paste in the fraction 0 - 0,250 mm. This new set-up is able to dry the material in very few seconds, divide it into two fractions (the coarse one and the fine one) thanks to the air and increase the amount of fines (0 - 0,250 mm) promoting the attrition between the particles through a vibration device. The coarse fraction is then processed in a ball mill in order to improve the result and reach the final goal. Thanks to the high temperature it is possible to markedly reduce the milling time. The sand 0 - 2 mm, after being heated and milled is used to replace 100% of norm sand in mortar production. The results are very promising: the mortar made with recycled sand reaches an early strength, in fact the increment with respect to the mortar made with norm sand is 20% after three days and 7% after seven days. With this research it has been demonstrated that once the temperature is increased it is possible to obtain a clean coarse fraction (0,250 - 4 mm), free from cement paste that is concentrated in the fine fraction 0 - 0,250 mm. The milling time and the drying time can be largely reduced. The recycled sand shows better performance in terms of mechanical properties with respect to the natural one.

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On a global level the population growth and increase of the middle class lead to a growing demand on material resources. The built environment has an enormous impact on this scarcity. In addition, a surplus of construction and demolition waste is a common problem. The construction industry claims to recycle 95% of this waste but this is in fact mainly downcycling. Towards the circular economy, the quality of reuse becomes of increasing importance. Buildings are material warehouses that can contribute to this high quality reuse. However, several aspects to achieve this are unknown and a need for more insight into the potential for high quality reuse of building materials exists. Therefore an instrument has been developed that determines the circularity of construction waste in order to maximise high quality reuse. The instrument is based on three principles: ‘product and material flows in the end of life phase’, ‘future value of secondary materials and products’ and ‘the success of repetition in a new life cycle’. These principles are further divided into a number of criteria to which values and weighting factors are assigned. A degree of circularity can then be determined as a percentage. A case study for a typical 70s building is carried out. For concrete, the circularity is increased from 25% to 50% by mapping out the potential for high quality reuse. During the development of the instrument it was clarified that some criteria are difficult to measure. Accurate and reliable data are limited and assumptions had to be made. To increase the reliability of the instrument, experts have reviewed the instrument several times. In the long-term, the instrument can be used as a tool for quantitative research to reduce the amount of construction and demolition waste and contribute to the reduction of raw material scarcity.

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This research project aims to improve economic, social and environmental sustainability of the pre-cast concrete and construction and demolition waste supply chains through the development, trial and evaluation of an innovative supply chain management strategy. The long-term goals are to improve competitive behaviour and market sector performance and improve business process efficiency and effectiveness of public sector program delivery by influencing policy development, changing organisational behaviour and implementation development to achieve more economic, social and environmental sustainable markets.

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O gerenciamento dos resíduos de construção civil configura-se ferramenta sistêmica, no qual se verifica a possibilidade do uso de um modelo de Sistema de Gerenciamento com a utilização de indicadores. O referencial teórico abordado, com conceitos e entendimentos sobre a responsabilidade socioambiental das organizações na disposição correta de seus resíduos, particularmente aqueles oriundos de construção civil como indutores e indicadores de responsabilidade social e ambiental, posicionamento estratégico e a responsabilidade socioambiental, delimitam a esfera financeira como um ativo intangível da empresa. Assim, o Balanced Scorecard, apresentado em suas quatro perspectivas: a financeira, a do cliente, a dos processos internos e a do aprendizado e crescimento, relacionam-se com a responsabilidade na gestão dos seus resíduos. Para avaliar a adequação dos indicadores e respectivas métricas, torna-se plausível a aplicação dos dez testes do Performance Prism. A gestão por indicadores é assim analisada na ótica das diferentes, porém integradas, perspectivas do Balanced Scorecard. A principal característica do modelo em estudo é a inserção da responsabilidade pelos resíduos às estratégias empresariais, conduzindo linearmente tais ações aos princípios da empresa. Os resultados apresentados após sua implementação em uma empresa de engenharia civil proporcionaram um reaproveitamento do entulho gerado da ordem de aproximados 52% como matéria-prima para agregados, comprovando a viabilidade de uso dos indicadores, integrando as ações de gerenciamento de resíduos às demais questões críticas e estratégicas da empresa.

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Num passado relativamente recente, o processo de demolição tem experimentado várias mudanças, que incidem principalmente na forma como o edifício ou estrutura vai ser demolido. Mais recentemente, o surgimento das preocupações ambientais levam hoje a falar de "desconstrução", em função do prejuízo das demolições. O termo desconstrução é usado para descrever o processo de desmantelamento e remoção seletiva de materiais de construção em vez da demolição tradicional. O sucesso da desconstrução vem em função do planeamento antecipado, da aplicação contínua das regras de segurança e da formação e informação para todos os trabalhadores. A triagem de materiais de demolição é de certa forma imposta pela preocupação das empresas que contribuem para a economia de recursos naturais. Esta metodologia é uma melhoria contínua, porém muito mais diversificados os materiais obtidos e a sua heterogeneidade. A correta gestão do fluxo de resíduos de construção e demolição é importante e o seu interesse na reciclagem de resíduos tem aumentado constantemente. Esse interesse é dirigido pelo grande volume desses materiais, os custos associados e uma maior consciência das oportunidades de reciclar. Auxiliando também no desenvolvimento dos mercados locais para os resíduos, tanto para os materiais que são diretamente reutilizados, como os que são reciclados, sendo novamente aplicados na construção civil. Esta dissertação aborda os métodos comummente utilizados na demolição de edifícios que dão mais atenção ao planeamento e execução dos trabalhos de demolição, garantindo a segurança no local de trabalho.

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The construction industry is responsible for generating a lot of waste because of their activities. Consequently, it is noticeable the occurrence of environmental problems in terms of its disposal in inappropriate places. Faced with this problem, some studies have been conducted with the aim of developing technologies and alternatives for recycling construction and demolition waste (CDW), motivated by the scarcity of natural resources and reduction of environmental problems generated. The research aims to characterize the recycled aggregates derived from construction and demolition waste (CDW) produced in the Greater Natal-RN and analyze the performance of mortar coating produced with recycled aggregates. The study includes the chemical , physical and microstructural characterization of recycled aggregates , as well as conducting microscopic analysis and laboratory tests in the fresh state (consistency index , water retention , bulk density and content of entrained air ) and in the hardened state ( compressive strength , tensile strength in bending , water absorption by immersion and capillary , mass density and void ratio ) for mortars produced from different levels of substitution of aggregates ( 0, 20 %, 40 %, 60 %, 80 % and 100 %). The results were satisfactory, providing mortars produced with recycled aggregates, smaller mass density and dynamic modulus values as well as an increase in the rates of absorption and porosity. The tensile strength in bending and compression for TP1 (1:2:8) trait were lower for mortars produced with recycled aggregates and the best result was 20% for replacement. For the TP2 (1:8) mapping, there was an increase in resistance to traction and compression and the best result was for 100% replacement of natural aggregates by recycled. The experiments led to the conclusion that the technical and economic point of view that the mortars produced with recycled aggregates can be used in construction, only if there is an effective control in production processes of recycled aggregate and at the dosage of mortars

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Surveys carried out in many Brazilian cities have shown that the CDW Construction and Demolition Waste, in some cases, represent more than 50% of the mass of urban solid residue. Municipalities have struggled to manage in an effective way huge quantities of CDW generated every day and solve the problem of the illegal dumping in an inadequate area, which compromise the quality of life of the population as a whole, thus causing serious problems concerning social-environmental and sanitary. This paperwork was meant it carry out environmental diagnosis of the management and the final destination of the CDW in the city of Parnamirim/RN. The methodology used in this work constituted in the bibliographical research, conducted to give support and fundaments to the subject in question, identification of the main places of legal and illegal dumping, identification of the environmental impacts caused by the irregular deposition of the CDW, valuation of quantity and quality of the CDW and perception according to the Environmental Legislation. The necessary data for the elaboration of this study were carried out through the appliance of questionnaires with open and closed questions, applied to 14 (fourteen) Real Estate developer companies associated with SINDUSCON/RN and 05 companies that deal with the transportation and collection of CDW, formal and informal interviews, exploitational visits and photographical records. The collected data went through a statistic treatment being organized into tables and graphs. The main results obtained from this research show that the interviewees hold a medium knowledge of the specific Environmental Legislation; do not have an effective model of environmental management, resorting to only reusing CDW; that the reusing of CDW is not substantial, as much as the possibility of recycling has a minimal consideration. It was also verified that a considerable percentage of interviewees affirmed to send CDW to illegal and inadequate locations. It is expected that such study can be used as an important tool to subsidize the public administration in the pursuit of solutions which could bring benefits to society and the environment

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An evaluation of the composition of soil cement bricks with construction and demolition waste. Sustainable development requires the existence of a production network that includes the reuse of construction waste for new materials. Current analysis investigates an optimal soil-cement composition made up of construction and demolition waste for the manufacture of pressed bricks. Soil-cement bricks were manufactured from construction and demolition wastes (CDW), A-4 classified fine sandy soil and cement CP II Z 32. Laboratory tests, comprising test compaction, optimum water content and maximum dry specific weight, consistency limits, grain size distribution and linear shrinkage, were made to characterize the materials researched. Compressive strength and absorption tests were also undertaken in different combinations of composition. Results showed that the application of CDW improved soil-cement qualities and reduced shrinkage of the material used.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)