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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.
111

Structural performance of construction and demolition waste-based geopolymer concrete columns under combined axial and lateral cyclic loading

Akduman, S., Aktepe, R., Aldemir, A., Ozcelikci, E., Yildirim, Gurkan, Sahmaran, M., Ashour, Ashraf 09 October 2023 (has links)
Yes / Construction and demolition waste (CDW) has reached severe environmental and economic dimensions due to its large volume among all solid waste, highlighting the importance of local actions to manage, recycle, and reuse CDW. Ductile demountable connections are necessary to disassemble and reuse the concrete structural members and fast assembly of precast structures in seismic regions without generating waste. In this study, the seismic performance of CDW-based reinforced geopolymer concrete columns has been investigated. Six ½ scaled columns (half of which were demountable and the other half monolithic) were experimentally tested under reversed cyclic lateral displacement excursions, considering three different levels of constant axial loading to determine failure mechanisms, load–displacement responses, ductilities, energy dissipation capacities, stiffness degradation relations, and curvature distributions. The obtained test results were used to determine the performance of CDWbased geopolymer concrete columns and compare the performances of the demountable connection with the monolithic connection. The test results showed that the novel demountable connection for precast concrete frames exhibited better seismic performance in terms of maximum lateral load capacity, initial stiffness, energy dissipation capacity, and maximum curvature than their monolithic counterparts. Besides, increasing the axial compression ratio on the columns caused an increase in lateral load capacity, energy dissipation capacity, energy dissipation ratio, and initial curvature stiffness; however, it decreased the ductility. Finally, the capacity predictions of current codes, i.e., TS500 and ACI318, were conservative when compared with experimental results. / This publication is a part of doctoral dissertation work by the first author in the Academic Program of Civil Engineering, Institute of Science, Hacettepe University. The authors gratefully acknowledge the financial assistance of the European Union’s Horizon 2020 research and innovation program under grant agreement No: 869336, ICEBERG (Innovative Circular Economy Based solutions demonstrating the Efficient recovery of valuable material Resources from the Generation of representative End-of-Life building material). This work was also supported by Newton Prize 2020. The fifth and seventh authors acknowledge the financial support received from the European Union’s Horizon 2020 research and innovation program under the Marie SkłodowskaCurie grant agreement No 894100. / The full-text of this article will be released for public view at the end of the publisher embargo on 4th Oct 2024.
112

An Investigation into Durability Aspects of Geopolymer Concretes Based Fully on Construction and Demolition Waste

Ozcelikci, E., Yildirim, Gurkan, Alhawat, Musab M., Ashour, Ashraf, Sahmaran, M. 30 March 2023 (has links)
Yes / The focus of the construction industry has shifted towards the development of al-ternative, eco-friendly and green construction materials due to the energy-inefficient and carbon-intensive nature of Portland cement (PC) production and aggregate quarrying. Meanwhile, increased number of repetitive re-pair/renovation/maintenance activities and demolition operations for the end-of-life buildings generate significant amounts of construction and demolition waste (CDW). For the purposes of sustainability and upcycling wastes into high-value-added materials with improved greenness, components from CDW streams can be used in producing geopolymer concretes without using PC and natural aggre-gates, given the rich aluminosiliceous nature of CDW components. The focus of current work is therefore on the analysis of durability of aspects (i.e., drying shrinkage and resistance against sulfate attack, cyclic freezing-thawing, and chlo-ride penetration) of geopolymer concretes made entirely of CDW. Different types of bricks, tile, concrete, and glass were used in mixed form as precursors for ge-opolymerization while different-size grains of waste concrete were used as recy-cled aggregates. As alkali activators, sodium hydroxide, calcium hydroxide and sodium silicate were used. In a companion mixture, CDW-based precursors were replaced with slag and class-F fly ash. Results showed that sulfate and cyclic freeze-thaw exposure did not cause any noticeable weight and compressive strength loss in CDW-based geopolymer concretes, while chloride penetration was found comparable to PC-based concrete. While drying shrinkage was found high in entirely CDW-based geopolymer concrete and resulted in surface mi-crocracks, it was possible to lower the drying shrinkage substantially via substi-tution of CDW-based precursors with fly ash and slag. / The authors also wish to thank the support of Scientific and Technical Research Council (TUBITAK) of Turkey provided under projects: 218M102 and 117M447. / This paper is from the fib Symposium 2023, Building for the future: Durable, Sustainable, Resilient. 5-7 Jun, Istanbul, Turkey.
113

Challenges and Opportunities of Reusing Materials in Construction (Sweden) : A PEST-SWOT Analysis

Inanloo, Peyman January 2024 (has links)
This thesis explores the challenges and opportunities of reusing construction and demolition waste within Sweden's construction sector, employing a PEST-SWOT analytical framework. The focus is on three primary materials prevalent in residential single-family houses: brick, concrete, and timber. The study identifies key political, economic, social, and technological factors that influence material reuse practices. The analysis highlights substantial barriers including regulatory complexities, lack of incentives, and the tendency to often prioritize new over reused materials due to perceived risks and higher costs associated with reuse. Despite these challenges, the research identifies significant opportunities for advancing material reuse. These include the potential for implementation of technological advancements in material processing, and growing public and governmental support for sustainable construction practices. The thesis goes forward by proposing strategic recommendations aimed at enhancing the adoption of reuse practices, thereby contributing to a more sustainable and resource-efficient construction sector in Sweden. / Demand trust for circular building materials
114

Estudo do sistema de gerenciamento integrado de resíduos de construção e demolição do município de São Carlos - SP / Study of the integrated management of construction and demolition wastes from São Carlos - SP

Córdoba, Rodrigo Eduardo 21 May 2010 (has links)
Com a intensificação da geração de resíduos sólidos urbanos, as autoridades, pesquisadores e sociedade têm voltado seus esforços para enfrentar as dificuldades de manejo e disposição final adequada desses resíduos. Neste sentido, é coerente afirmar que os resíduos de construção e demolição (RCD) fazem parte dessa problemática, pois geralmente representam a maioria dos resíduos sólidos gerados no meio urbano. A ausência de políticas públicas em relação à gestão e gerenciamento desses resíduos tem provocado diversos impactos como, por exemplo, o surgimento de vários depósitos clandestinos nas áreas mais afastadas do perímetro urbano e gastos por parte da administração pública com modelos de gestão corretiva. Entretanto, esse modelo corretivo tem se demonstrado obsoleto e ineficaz para minimizar os impactos negativos gerados pela deposição irregular de RCD. Diante desses fatos, foi criada a Resolução CONAMA nº 307/2002, que instituiu que os municípios devem prover políticas públicas voltadas a evitar o descarte dos RCD em locais irregulares e que contemplem a minimização dos impactos causados ao meio ambiente e saúde humana. Assim, com intuito de contribuir nesta área de conhecimento a presente pesquisa teve por finalidade estudar a situação do sistema de gerenciamento integrado de RCD do município de São Carlos-SP, após a regulamentação da Resolução CONAMA nº 307/2002. Para tanto, foi realizado um levantamento da situação atual do gerenciamento dos RCD no município, por meio de quatro etapas de estudo - contextualização dos indicadores básicos locais; caracterização quantitativa; caracterização qualitativa e por fim análise das áreas de descarte clandestino e áreas de implantação de pontos de captação para pequenos volumes de RCD. Com base nos resultados obtidos neste estudo, foi possível verificar que o município de São Carlos possui um Plano Integrado de Gerenciamento de RCD, em consonância com a Resolução CONAMA nº 307/2002. Porém pode-se constatar que o respectivo município não possui implantada uma rede de captação que contemple os pequenos volumes, assim este sofre com o aumento de áreas de descarte clandestino, as quais causam diversos impactos ao meio ambiente e saúde pública local. Entretanto, medidas adotadas neste novo sistema também demonstraram fatores positivos como a redução de descartes em aterros e geração de emprego e renda. Por fim, esta pesquisa implementou uma metodologia de caracterização dos RCD por análise de imagens, a qual se demonstrou eficiente na caracterização de amostras que apresentavam peças com grandes volumes como, por exemplo, vigas, pilares e placas de concreto. / With the increased generation of urban solid wastes, the authorities, researchers and society have turned their efforts to tackle the difficulties of handling and final disposal of such wastes. In this sense, it is consistent to say that the construction and demolition wastes (C&D) are part of this problem, because they generally represent the majority of solid waste generated in urban areas. The absence of public politics regarding the management of such waste have caused many impacts, for example, illegal discharges dumping sites in areas furthest from the urban perimeter and spending by the government with corrective models. However, this corrective model has proven obsolete and ineffective to minimize the negative impacts caused by the irregular disposal of C&D wastes. Given these facts, the resolution nº 307/2002 of the National Environmental Council (CONAMA) for the C&D wastes was created, which established that municipalities must provide public politics that aim at preventing the disposal of C&D wastes at irregular areas and reduce impacts to the environment and human health. Therefore, to contribute to this area of knowledge this research studied the situation of the integrated management system of C&D wastes from São Carlos-SP, after the implementation of resolution nº 307. For this, a survey was done of the current situation of management of C&D wastes in the city through four stages - local contextualization of basic indicators, quantitative characterization, qualitative characterization and finally analysis of areas of irregular discharge and areas of implantation of points for small volumes of C&D wastes. Based on the results of this study, we observed that the municipality of São Carlos has an Integrated Waste Management of C&D wastes, according to resolution nº 307. However, it was found that the municipality has not established a system of small volumes, so it suffers with increasing areas of irregular disposal, which causes many impacts to the environment and local public health. However, measures taken in this new system also demonstrated positive factors such as the reduction of discards in landfills and the generation of employment and income. Finally, this study implemented a methodology to characterize the C&D by image analysis, which has demonstrated effectiveness in the characterization of samples with high volume parts such as beams, pillars and slabs of concrete.
115

Estudo do sistema de gerenciamento integrado de resíduos de construção e demolição do município de São Carlos - SP / Study of the integrated management of construction and demolition wastes from São Carlos - SP

Rodrigo Eduardo Córdoba 21 May 2010 (has links)
Com a intensificação da geração de resíduos sólidos urbanos, as autoridades, pesquisadores e sociedade têm voltado seus esforços para enfrentar as dificuldades de manejo e disposição final adequada desses resíduos. Neste sentido, é coerente afirmar que os resíduos de construção e demolição (RCD) fazem parte dessa problemática, pois geralmente representam a maioria dos resíduos sólidos gerados no meio urbano. A ausência de políticas públicas em relação à gestão e gerenciamento desses resíduos tem provocado diversos impactos como, por exemplo, o surgimento de vários depósitos clandestinos nas áreas mais afastadas do perímetro urbano e gastos por parte da administração pública com modelos de gestão corretiva. Entretanto, esse modelo corretivo tem se demonstrado obsoleto e ineficaz para minimizar os impactos negativos gerados pela deposição irregular de RCD. Diante desses fatos, foi criada a Resolução CONAMA nº 307/2002, que instituiu que os municípios devem prover políticas públicas voltadas a evitar o descarte dos RCD em locais irregulares e que contemplem a minimização dos impactos causados ao meio ambiente e saúde humana. Assim, com intuito de contribuir nesta área de conhecimento a presente pesquisa teve por finalidade estudar a situação do sistema de gerenciamento integrado de RCD do município de São Carlos-SP, após a regulamentação da Resolução CONAMA nº 307/2002. Para tanto, foi realizado um levantamento da situação atual do gerenciamento dos RCD no município, por meio de quatro etapas de estudo - contextualização dos indicadores básicos locais; caracterização quantitativa; caracterização qualitativa e por fim análise das áreas de descarte clandestino e áreas de implantação de pontos de captação para pequenos volumes de RCD. Com base nos resultados obtidos neste estudo, foi possível verificar que o município de São Carlos possui um Plano Integrado de Gerenciamento de RCD, em consonância com a Resolução CONAMA nº 307/2002. Porém pode-se constatar que o respectivo município não possui implantada uma rede de captação que contemple os pequenos volumes, assim este sofre com o aumento de áreas de descarte clandestino, as quais causam diversos impactos ao meio ambiente e saúde pública local. Entretanto, medidas adotadas neste novo sistema também demonstraram fatores positivos como a redução de descartes em aterros e geração de emprego e renda. Por fim, esta pesquisa implementou uma metodologia de caracterização dos RCD por análise de imagens, a qual se demonstrou eficiente na caracterização de amostras que apresentavam peças com grandes volumes como, por exemplo, vigas, pilares e placas de concreto. / With the increased generation of urban solid wastes, the authorities, researchers and society have turned their efforts to tackle the difficulties of handling and final disposal of such wastes. In this sense, it is consistent to say that the construction and demolition wastes (C&D) are part of this problem, because they generally represent the majority of solid waste generated in urban areas. The absence of public politics regarding the management of such waste have caused many impacts, for example, illegal discharges dumping sites in areas furthest from the urban perimeter and spending by the government with corrective models. However, this corrective model has proven obsolete and ineffective to minimize the negative impacts caused by the irregular disposal of C&D wastes. Given these facts, the resolution nº 307/2002 of the National Environmental Council (CONAMA) for the C&D wastes was created, which established that municipalities must provide public politics that aim at preventing the disposal of C&D wastes at irregular areas and reduce impacts to the environment and human health. Therefore, to contribute to this area of knowledge this research studied the situation of the integrated management system of C&D wastes from São Carlos-SP, after the implementation of resolution nº 307. For this, a survey was done of the current situation of management of C&D wastes in the city through four stages - local contextualization of basic indicators, quantitative characterization, qualitative characterization and finally analysis of areas of irregular discharge and areas of implantation of points for small volumes of C&D wastes. Based on the results of this study, we observed that the municipality of São Carlos has an Integrated Waste Management of C&D wastes, according to resolution nº 307. However, it was found that the municipality has not established a system of small volumes, so it suffers with increasing areas of irregular disposal, which causes many impacts to the environment and local public health. However, measures taken in this new system also demonstrated positive factors such as the reduction of discards in landfills and the generation of employment and income. Finally, this study implemented a methodology to characterize the C&D by image analysis, which has demonstrated effectiveness in the characterization of samples with high volume parts such as beams, pillars and slabs of concrete.
116

Straßennetzanalyse in ländlichen Räumen mit Bevölkerungsrückgang

Hein, Ines 22 June 2016 (has links) (PDF)
Die Straßenunterhaltung stellt in Deutschland Bund, Länder, Landkreise und Gemeinden vor eine finanzielle Herausforderung, die es zu lösen gilt. Die vorliegende Arbeit bietet dazu Landkreisen und Gemeinden eine Methode, Straßenunterhaltungskosten langfristig zu senken. Die Methode ist dabei auf einen Straßenkomplettrückbau ausgelegt. Zur Identifizierung rückbaugeeigneter Straßen werden quantitative und qualitative Kriterien vorgestellt. Zu den quantitativen Kriterien zählen die Ver-gleichsgrößen: Mehraufwandsleistung und der Mehraufwand X-Wert. Als Mehraufwand wird die zusätzliche Reisezeit bezeichnet, die ohne die Straße bewältigt werden müsste. Die Mehraufwands-leistung gibt die Mehraufwände aller Nutzer einer Straße pro Tag wieder. Je höher die Verkehrsmenge einer Straße, desto höher ist die Mehraufwandsleistung. Der Mehraufwand X-Wert beschreibt den Mehraufwand pro Person eines Ortes. Zur Bestimmung der Wichtigkeit einer Straße werden beide Größen gewichtet zusammengefasst. Zur Berechnung der Vergleichsgrößen wurden im Vorfeld Ent-scheidungen getroffen, so besteht der Mehraufwand nur aus der Fahrzeit. Die Fahrzeit wird für lokal begrenzte Verbindungen wie dem täglichen Einkauf, Erledigungen, Bildung, innerwöchentliche Frei-zeitaktivitäten und Begleitwegen ermittelt, die ungefähr innerhalb eines 30-km-Radius erreichbar sind, sowie für Arbeitswege mit Fahrzeiten bis 1:45 Stunden. Wirtschaftsverkehr wird nicht berechnet. Die Routen der betrachteten Verbindungen werden für den motorisierten Verkehr, den nichtmotorisierten Verkehr und den öffentlichen Personennahverkehr berechnet. Zur Routenermittlung werden Quelle-Ziel-Beziehungen genutzt, deren Routen über Straßen verlaufen, die für das jeweilige Verkehrsmittel zugelassen sind und die Verkehrsmenge aufnehmen können. Eine flexible Zielwahl wird berücksichtigt. Für Straßen mit geringer Wichtigkeit wird anhand der qualitativen Kriterien geprüft, ob die Straßen wirklich rückbaugeeignet sind. Dazu werden die Themen: Rettungsdienst, Nahversorgung, ganzjährige Erreichbarkeit, öffentlicher Verkehr, Dienstleister, Lärm, Sicherheit und weitere Kriterien bedacht. Nur für rückbaugeeignete Straßen wird das Einsparpotential kalkuliert. Dazu nennt die Arbeit entsprechende Kostensätze. Ziel der Arbeit war es, diese Methode zu entwickeln und deren Anwendbarkeit zu prüfen. Die Methode ist umsetzbar. Die benötigten Daten sind beschaffbar. Die Objektivität der Methode ist durch die Anpassbarkeit an die Ziele des Untersuchungsgebiets vor bewusst herbeigeführter Scheinobjektivität nicht geschützt. Weiterer Forschungsbedarf besteht zur Implementierung eines öffentlichen Verkehrs-Verbindung-Tools, welches die Fahrtmöglichkeiten pro Tag ausgibt, und zu einer vergleichenden Bewertungsmethode von Aufwandserhöhungen verschiedener Routen mit Bezug zum gegenwärtigen Aufwand kommt.
117

Straßennetzanalyse in ländlichen Räumen mit Bevölkerungsrückgang

Hein, Ines 07 June 2016 (has links)
Die Straßenunterhaltung stellt in Deutschland Bund, Länder, Landkreise und Gemeinden vor eine finanzielle Herausforderung, die es zu lösen gilt. Die vorliegende Arbeit bietet dazu Landkreisen und Gemeinden eine Methode, Straßenunterhaltungskosten langfristig zu senken. Die Methode ist dabei auf einen Straßenkomplettrückbau ausgelegt. Zur Identifizierung rückbaugeeigneter Straßen werden quantitative und qualitative Kriterien vorgestellt. Zu den quantitativen Kriterien zählen die Ver-gleichsgrößen: Mehraufwandsleistung und der Mehraufwand X-Wert. Als Mehraufwand wird die zusätzliche Reisezeit bezeichnet, die ohne die Straße bewältigt werden müsste. Die Mehraufwands-leistung gibt die Mehraufwände aller Nutzer einer Straße pro Tag wieder. Je höher die Verkehrsmenge einer Straße, desto höher ist die Mehraufwandsleistung. Der Mehraufwand X-Wert beschreibt den Mehraufwand pro Person eines Ortes. Zur Bestimmung der Wichtigkeit einer Straße werden beide Größen gewichtet zusammengefasst. Zur Berechnung der Vergleichsgrößen wurden im Vorfeld Ent-scheidungen getroffen, so besteht der Mehraufwand nur aus der Fahrzeit. Die Fahrzeit wird für lokal begrenzte Verbindungen wie dem täglichen Einkauf, Erledigungen, Bildung, innerwöchentliche Frei-zeitaktivitäten und Begleitwegen ermittelt, die ungefähr innerhalb eines 30-km-Radius erreichbar sind, sowie für Arbeitswege mit Fahrzeiten bis 1:45 Stunden. Wirtschaftsverkehr wird nicht berechnet. Die Routen der betrachteten Verbindungen werden für den motorisierten Verkehr, den nichtmotorisierten Verkehr und den öffentlichen Personennahverkehr berechnet. Zur Routenermittlung werden Quelle-Ziel-Beziehungen genutzt, deren Routen über Straßen verlaufen, die für das jeweilige Verkehrsmittel zugelassen sind und die Verkehrsmenge aufnehmen können. Eine flexible Zielwahl wird berücksichtigt. Für Straßen mit geringer Wichtigkeit wird anhand der qualitativen Kriterien geprüft, ob die Straßen wirklich rückbaugeeignet sind. Dazu werden die Themen: Rettungsdienst, Nahversorgung, ganzjährige Erreichbarkeit, öffentlicher Verkehr, Dienstleister, Lärm, Sicherheit und weitere Kriterien bedacht. Nur für rückbaugeeignete Straßen wird das Einsparpotential kalkuliert. Dazu nennt die Arbeit entsprechende Kostensätze. Ziel der Arbeit war es, diese Methode zu entwickeln und deren Anwendbarkeit zu prüfen. Die Methode ist umsetzbar. Die benötigten Daten sind beschaffbar. Die Objektivität der Methode ist durch die Anpassbarkeit an die Ziele des Untersuchungsgebiets vor bewusst herbeigeführter Scheinobjektivität nicht geschützt. Weiterer Forschungsbedarf besteht zur Implementierung eines öffentlichen Verkehrs-Verbindung-Tools, welches die Fahrtmöglichkeiten pro Tag ausgibt, und zu einer vergleichenden Bewertungsmethode von Aufwandserhöhungen verschiedener Routen mit Bezug zum gegenwärtigen Aufwand kommt.
118

Material characterisation and response modelling of recycled concrete and masonry in pavements

Barisanga, Fabrice 04 1900 (has links)
Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The global quest for sustainability has intensified the requirement for waste recycling in a number of countries. Waste recycle includes Construction and Demolition Waste (CDW), which emanates from the demolition of buildings and other civil engineering structures. In Europe, the United States, China, and Australia, waste recycling has proven to be successful, both structurally and functionally. In particular, the consideration and /or use of CDW in pavement layers remain on the increase. However, in Southern Africa the use and/or application of CDW and its allied practice is limited; the abundant natural aggregates, the lack of knowledge and technical expertise besides the availability of suitable CDW remain the prominent reasons for its limited consideration. In this research, recycled material infers to Construction and Demolition Waste pertaining to Recycled Concrete and Masonry (RCM). The quality and the type of RCM vary from region to region and as a result, quality control measures aimed at limiting the inconsistency are usually required. Results revealed that secondary crushing influences the physical and mechanical behaviour of RCM aggregates; this information remains insightful in terms of material gradation, performance and viability. The compaction protocol followed and its findings revealed that the initial material grading lightly changed after compaction. However, the 10% FACT results showed that the RCM aggregates exhibit less degradation due to crushing when dry than when they are wet. It is eminent that compaction and/or densification are a cheaper method to improve the pavement layer structural capacity. However, this is reliant on material characteristics, quality, and type. With this cognisance, an experimental program in line with RCM aimed at assessing the mechanical behaviour was developed. The experimental variables include mix composition, mixing and compaction moisture as well as degree of compaction and/or compactive effort. In general, the laboratory evaluation and analysis of the results showed that the mix composition in addition to compaction moisture and the degree of compaction were influential to the obtained shear strength, resilient modulus and Poisson Ratio. Particularly, mix composition exhibited relatively higher influence on the resilient modulus while the compaction moisture effect on the Poisson Ratio dominated other investigated variables such as mix composition and the degree of compaction. Shear strength and resilient response results show that RCM exhibits significant shear strength due to its cohesion, and satisfactory resilient modulus. Pavement analysis and design using multi-layer linear-elastic model and transfer functions in pavement layers where RCM is used also revealed that this material could perform satisfactorily. It was deduced that RCM is a viable material type to consider in the construction of pavement layers that carry low to moderate levels of traffic. / AFRIKAANSE OPSOMMING: Die globale beweging na meer onderhoubare aktiwiteite het gelei tot die ʼn toename in vereistes met betrekking tot herwinning van rommel. Rommelherwinning sluit materiaal van bouwerke en ander siviele strukture in. In Europa, Amerika, China en Australië het die herwinning van afval materiaal tot groot sukses gelei. Spesifiek die gebruik van geselekteerde bourommel in padlae bleik om toe te neem. In Suid -Afrika word die materiaal net in enkele geïsoleerde gevalle gebruik as gevolg van die onderbreking van tegniese kennis met betrekking tot die toeganklikheid en bruikbaarheid van die materiaal. Ook, tans geniet die gebruik van gebreekte klip voorrang omdat die verbruiker glo dat daar nog baie van hierdie materiaal beskikbaar is. In hierdie navorsing verwys bourommel spesifiek na herwinde beton en boustene. Die “kwaliteit” van boustene in verskillende gebiede varieer en as ‘n gevolg moet kwaliteitskontroles toegepas word om hierdie te beperk. Resultate in diè navorsing het gewys dat sekondêre klipbreking/vergruising die fisiese en meganiese gedrag van “bourommel aggregaat” beïnvloed. Die 10% FACT (Fynstof Aggregaat Breekwaarde) resultate het ook gewys dat geselekteerde bourommel minder degradasie ondervind as dit droog is in vergelyking met nat materiaal. Goeie kompaksie van die tipe materiale word erken as een van die goedkoopste maniere om die gedrag daarvan in plaveisellae te verbeter. Dit is wel afhanklik van materiaal karakteristieke, kwaliteit en tipe materiaal. Hierdie faktore is ingesluit in die eksperimentele plan wat eienskappe soos mengsel komposisie, meng en kompaksie voginhoud sowel as graad van kompaksie insluit. Die resultate van die laboratorium analise het gewys dat die mengkomposisie, vog tydens kompaksie en graad van kompaksie ʼn invloed op die skuifsterkte, veerkragsmodulus en die Poisson verhouding het. Veral die mengkomposisie het ʼn merkwaardige invloed op die veerkragmodulus gehad, terwyl die voginhoud tydens kompaksie die grootste invloed op die Poissonverhouding gehad het. Die skuifsterkte (agv hoë kohesie) en veerkragsmodulus van geselekteerde bourommel dui aanvaarbare resultate vir die gebruik in paaie, spesifiek in padlae waar lae spanningsvlakke ondervind word,soos deur liniere elastiese berekeninge gewys is.
119

Impact of different construction methods for concrete buildings on waste management

Loong, Cheuk-yui, Michael., 龍焯銳. January 2004 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
120

Estudo do potencial de contaminação de lixiviados gerados em aterros de resíduos da construção civil por meio de simulações em colunas de lixiviação / Study of the pollution potential of leachate of construction and demolition wastes landfills in lysimeters

Córdoba, Rodrigo Eduardo 27 June 2014 (has links)
No Brasil, a Resolução CONAMA nº 307/2002 e a Resolução CONAMA nº 448/2012 definem que os resíduos da construção civil (RCC) classe A, caso não sejam reutilizados ou reciclados na forma de agregados, devem ser destinados para aterros de resíduos classe A de reservação de material para usos futuros. Porém, pequenas quantidades de resíduos de outras classes, e resíduos não inertes acabam dispostos neste tipo de aterro. Esse fato pode ser agravado devido esses aterros não possuírem impermeabilização de base e sistemas de drenagem de lixiviados, o que pode favorecer a migração desses lixiviados de RCC para reservas de água, e colocar em risco a saúde da população e o meio ambiente. Com intuito de contribuir nessa área de conhecimento o presente estudo teve por finalidade investigar o potencial de contaminação de lixiviados de aterros de resíduos da construção civil por meio de simulações em colunas de lixiviação. Para tanto, foi realizado um estudo por meio de duas etapas &#8211 simulação de lixiviação de amostras de RCC em colunas de lixiviação (saturadas e não saturadas), e coleta de água subterrânea do aterro de RCC classe A. Resultados da pesquisa apontaram que as amostras de agregados de RCC classe A foram classificadas, de acordo com a NBR 10.004 (ABNT, 2004), como sendo resíduos não perigosos e não inertes &#8211 Classe II A. A hipótese tema do estudo foi verificada, a qual apontou que existe potencial de contaminação dos lixiviados gerados em aterros de RCC Classe A, os quais podem vir a poluir ou contaminar o solo e as águas subterrâneas inviabilizando o uso dessas águas para consumo humano. As concentrações máximas dos lixiviados de RCC que excederam o valor máximo permitido para consumo humano nas simulações foram: sulfato (950 mg/L), dureza (11.280 mg/L), cor (124 uH), Pb (0,36 mg/L), Cd (0,075 mg/L), Ni (0,088 mg/L), Fe (0,658 mg/L), Ba (1,205 mg/L), Cr (0,125 mg/L), Mn (0,297 mg/L), e Al (3,44 mg/L). A pesquisa também contribuiu para melhoria de projetos, execução e controle de aterros de resíduos da construção civil, a fim de futuramente equacionar possíveis impactos negativos gerados por esse tipo de resíduo ao solo e recursos hídricos. / In Brazil, the resolutions nº 307/2002 and nº 448/2012 of the National Environmental Council (CONAMA) define that the construction and demolition (C&D) class A - reusable or recyclable wastes as aggregates, such as ceramic components, grout and concrete -, if not reused or recycled as aggregates, should be going to C&D wastes landfill. These wastes must be disposed in the soil for the reservation of segregated materials for future use or future use of the area. However, these landfills receive small quantities of wastes from other sources and non-inert wastes. This fact can be aggravated because the C&D wastes are disposed in these unlined landfills and without drains of leachate. In this context, the C&D wastes leachate may migrate to water supplies causing risks to both human health and the environment. In an attempt to contribute to this area of knowledge, this project aims to investigate the pollution potential of leachate of construction and demolition wastes landfills in lysimeters. A survey will be conducted in two stages &#8211 simulation of leachate samples of C&D wastes lysimeters (saturated and unsaturated), and study of the C&D wastes landfill of the city through the collection of groundwater. Results of the research classified, for metals, the samples of aggregates of C&D wastes class A &#8211 such as ceramic components (bricks, blocks), grout and concrete &#8211 as non-hazardous and non-inert. The pollution of leachate of C&D wastes landfills was observed. The presence of these contaminants could affect the use of this water for human consumption. The parameters that exceeded the maximum value for human consumption were: sulfate (950 mg/L), hardness (11,280 mg/L), color (124 uH), Pb (0.36 mg/L), Cd (0.075 mg/L), Ni (0.088 mg/L), Fe (0.658 mg/L), Ba (1,205 mg/L) Cr (0.125 mg/L) Mn (0,297 mg/L), and Al (3.44 mg/L ).The research identified requirements for improvement projects, execution and control of C&D wastes landfills to minimize future potential adverse impacts generated by these residues in water resources.

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