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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.
381

Recyklované kamenivo do asfaltových směsí pozemních komunikací / Recycled aggregates to asphalt mixtures of the flexible pavements

Kropáč, Pavel January 2013 (has links)
This thesis deals with the theoretical part of the creation, distribution and recycling of construction and demolition waste. Subsequently covers made from these recycled construction and demolition waste and its potential application in structural layers of the pavement. In the practical part of the thesis deals with monitoring the overall properties of nine asphalt mixtures with different proportion of recycled concrete aggregate and asphalt binder, which are designed and intended for bed asphalt pavement. The recycled concrete aggregate and asphalt are performed various laboratory tests, the results are subjected to a comparison with the relevant standards and TP 210. The conclusion is made price comparisons of asphalt mixtures.
382

Water contents and lithium isotope compositions of the Mesozoic-Cenozoic lithospheric mantle of eastern North China Craton : constraints from peridotite xenoliths / Teneur en eau et composition isotopique du Lithium du manteau lithosphérique mésozoïque à cénozoïque du craton Nord Est Chinois : contraintes apportées par les xénolites de péridotite

Li, Pei 22 November 2012 (has links)
Pour mieux comprendre le processus géodynamique qui a permis la destruction du craton Nord Chinois (NCC), le rôle des fluides mantelliques a été examiné. Pour cela, les distributions des teneurs en eau et des compositions isotopiques du Lithium dans le manteau lithosphérique NCC ont été déterminées à partir des xénolites de péridotite entrainés par les basaltes mésozoïques et cénozoïques. Une variation temporelle des teneurs en eau est observée. Le manteau lithosphérique cénozoïque est appauvri en eau, sans doute suite à l'amincissement crustal et au réchauffement du manteau résiduel par un flux ascendant asthénosphérique. Le manteau lithosphérique mésozoïque montre des teneurs en eau intermédiaire entre les teneurs élevées du Crétacé et les teneurs basses cénozoïques, indiquant une déshydratation du manteau commençant dès le début de sa destruction. Cette déshydratation, facilitée par la destruction du manteau lithosphérique profond, permet de renforcer la rigidité de la lithosphère et lui permet de résister à la convection mantellique. Les distributions élémentaire et isotopique du Li montrent une grande hétérogénéité, aux échelles intra et inter-cristallines. Par simulation numérique, nous démontrons que deux enrichissements successifs ont affecté le manteau, un enrichissement limité (<5ppm) avec une signature pauvre en 7Li ([delta]7Li ~ -20 [pour mille]), suivi d'un enrichissement important (> 100 ppm) avec une signature riche ([delta]7Li ~ +20 [pour mille]), précédent de peu l'exhumation des xénolites. La formation des liquides métasomatiques responsables de ces enrichissements nécessite une distribution hétérogène dans le manteau NCC d'éléments recyclés lors de la subduction à l'est du NCC / In order to investigate the geodynamic cause for destruction of the North China Craton (NCC), the role of mantle fluids is examined. The aim of the PHD work is to clarify H2O contents and lithium isotopic compositions of the NCC lithospheric mantle by studying peridotite xenoliths hosted by Mesozoic-Cenozoic basalts across eastern NCC. A temporal variation of H2O content has been revealed, and it has deep implications for processes of craton destruction. The Cenozoic lithospheric mantle was featured by low H2O content, interpreted to be the relict mantle that survived the lithospheric thinning and has been dewatered by reheating from upwelling asthenospheric flow. The late-Mesozoic lithospheric mantle showed relatively high H2O content, a hydrous status intermediate between the Cretaceous hydration and the Cenozoic dryness, indicating the dehydration of the NCC mantle with time during NCC destruction. The dehydration, facilitated by thinning of weak mantle pieces at bottom, is one way by which the lithosphere strengthens itself to survive in the convecting mantle. Extreme Li and isotopic disequilibria were observed intra- and inter-mineral in the peridotites. With numerical simulations, we demonstrate two superimposed Li enrichment events occurring at the mantle: a limited Li enrichment (< 5 ppm) and large delta7Li depletion (-20~-10[per 1000]) of the mantle domain, followed by a recent and transient infiltration of high Li and delta7Li (up to +20 [per 1000]) melts/fluids. The anomalous Li isotopic compositions of mantle metasomatic agents call upon the same of their mantle sources, and we assume recycled components, both Li isotopically heavy and light, in the mantle beneath the eastern NCC
383

Estudo sobre a aplicação de agregado reciclado de concreto em construção de pavimentos / Study on application of recycled concrete aggregate in pavement construction

Sousa, Wallace Fioravanti de 21 September 2011 (has links)
A exploração dos recursos naturais e a degradação do meio ambiente têm sido fonte de preocupação no âmbito mundial. A busca por soluções alternativas que não causem ou que diminuam os impactos ambientais tornou-se comum na sociedade. Nesse contexto, a pavimentação vem contribuindo significativamente com soluções alternativas para destinação final de diversos tipos de resíduos, principalmente os oriundos da indústria da construção civil que sempre foi uma das maiores geradoras. Os resíduos da construção e demolição (RCD) podem ser transformados em agregados reciclados de ótima qualidade e podem ser aplicados em diversos serviços de engenharia. Os agregados reciclados, segundo a NBR 15116 (ABNT, 2004), são separados em misto e de concreto (ARC). No Brasil existem poucas pesquisas com o ARC, no entanto, as que existem e as pesquisas internacionais relatam que uma característica marcante do ARC é a cimentação própria. Portanto, o objetivo desta pesquisa é estudar o comportamento mecânico, ao longo do tempo de cura, do agregado reciclado de concreto proveniente da Usina de Reciclagem de São Carlos e de sua mistura com um solo laterítico, a fim de utilizá-los na construção de pavimentos. O estudo envolveu a análise dos resultados de resistência à compressão simples, módulo tangente, módulo de resiliência, deformação permanente e índice de suporte Califórnia (CBR) de corpos-de-prova de ARC e da sua mistura com solo laterítico, moldados em diferentes energias de compactação e ensaiados com tempos de cura variados. Ao final, concluiu-se que o agregado reciclado de concreto (ARC) é uma alternativa para construção de bases de pavimentos, podendo também substituir o agregado natural da mistura solo arenoso laterítico - brita descontínua, muito utilizada nas rodovias do interior de São Paulo. / Natural resources exploitation and the environmental degradation are a worldly problem nowadays. Searching for alternative solutions is something usual in most countries. Pavement systems are now contributing significantly with these alternative solutions by using the waste of construction demolition. This specific kind of waste can turn into mixed recycled aggregate or recycled concrete aggregate. There are just few researches in Brazil about the use of recycled concrete aggregate (RCA), however international researches have shown that this aggregate has a very characteristic and positive mark: self cementation. This research has got the objective of studying the mechanic behavior of the recycled concrete aggregate and its mix with lateritic soil on the construction of base pavements with different analytic basis. The study involved the analysis of the laboratorial tests results of the unconfined compressive strength, tangent modulus, resilient modulus, permanent deformation and California Bearing Ration (CBR) of RCA specimens and its mix with lateritic soil, molded in different compaction energy and tested in different curing times. In conclusion, this kind of recycled aggregate has proved to be a sustainable alternative for the natural aggregate in the construction of many roads in small cities of the State of São Paulo - Brazil.
384

An?lise da viabilidade de aplica??o de res?duos da constru??o civil da Regi?o Metropolitana de Campinas em argamassas de uso geral por m?todo multicrit?rios / Analysis of the feasibility of applying construction waste from the Metropolitan Region of Campinas to mortars of general use by multi-criteria method

Petitto, R?gia Mara 21 June 2017 (has links)
Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-08-07T13:10:24Z No. of bitstreams: 1 R?GIA MARIA PETITTO.pdf: 3577833 bytes, checksum: 125f036f5ae5942ebbd9906d675670d3 (MD5) / Made available in DSpace on 2017-08-07T13:10:24Z (GMT). No. of bitstreams: 1 R?GIA MARIA PETITTO.pdf: 3577833 bytes, checksum: 125f036f5ae5942ebbd9906d675670d3 (MD5) Previous issue date: 2017-06-21 / The objective of this work was to characterize the recycled aggregates generated in the metropolitan region of Campinas and to test its application in the production of mortars for general use. From a qualitative approach, with an exploratory objective, the surveys of the current legislation and legal requirements imposed to solid waste management and the panorama of this management in the metropolitan region of Campinas were carried out. The six recycling plants for the disposal of construction waste (RCC) generated in the implanted municipalities were identified and, based on the data collected, a map with the geographic location of these plants was elaborated. After the sample collection, with a quantitative approach of applied nature and exploratory objective, analyzes of the physical characteristics were made (grain size composition, 75 ?m sieve material, water absorption, clay cladding content and friable materials, Specific mass and organic impurity) and chemical (soluble salts and organic matter content by fire loss) of these materials. All the analyzed aggregates presented satisfactory results in the granulometric composition and water absorption tests. Regarding the content of fine material (less than 75 ?m), clay content and friable materials and organic impurities, few samples could be accepted for use recommended by the Brazilian Association of Technical Standards (ABNT). The analysis of the soluble salts content would also make it impossible to accept the aggregate of some suppliers. With the replacement of natural aggregate by the recycled aggregates, mortars with a 1: 3 dash (cement: aggregate) were prepared, and 20 and 40% of the natural aggregate were replaced. The characteristics of the mortars in the fresh state (water retention, incorporated air content, mass density) and hardened (water absorption by capillarity, capillary coefficient, compressive strength, flexural tensile strength and apparent specific mass in the Hardened state). From the results obtained, the analytical Hierarchy Process (AHP) methodology showed the content of incorporation of the recycled aggregate in the production of general purpose mortars composed of cement and sand. For the application of this method, weights were assigned to punctuated criteria related to the physical and mechanical performance of mortars and environmental criteria related to the exhaustion of natural resources and transport distance. The best result was found in mortar with a 20% substitute content of mixed recycled aggregate by municipal unit from Campinas, but it is not possible to observe a tendency to obtain better results in mortars with lower substitution content, nor exclusively by mortars with mixed recycled aggregates. / O presente trabalho teve por objetivo caracterizar os agregados reciclados gerados na regi?o metropolitana de Campinas e testar sua aplica??o na produ??o de argamassas para uso geral. A partir de uma abordagem qualitativa, com objetivo explorat?rio, foram realizados os levantamentos da legisla??o vigente e exig?ncias legais impostas ? gest?o dos res?duos s?lidos e do panorama desta gest?o na regi?o metropolitana de Campinas. As seis usinas recicladoras para destina??o dos res?duos de constru??o civil (RCC) gerados nos munic?pios implantadas foram identificadas e, a partir dos dados coletados, elaborou-se um mapa com a localiza??o geogr?fica destas usinas. Ap?s a coleta de amostras, com abordagem quantitativa de natureza aplicada e objetivo explorat?rio, foram realizadas an?lises das caracter?sticas f?sicas (composi??o granulom?trica, teor de material passante na peneira de 75 ?m, absor??o de ?gua, teor de torr?es de argila e materiais fri?veis, massa espec?fica e impureza org?nica) e qu?micas (sais sol?veis e teor de mat?ria org?nica por perda ao fogo) destes materiais. Todos os agregados analisados apresentaram resultados satisfat?rios nos ensaios de composi??o granulom?trica e absor??o de ?gua. J? quanto ao teor de material fino (menor que 75 ?m), teor de torr?es de argila e materiais fri?veis e impurezas org?nicas, foram poucas as amostras que poderiam ser aceitas para o emprego recomendado pela Associa??o Brasileira de Normas T?cnicas (ABNT). A an?lise do teor de sais sol?veis tamb?m inviabilizaria a aceita??o do agregado de alguns fornecedores. Com a substitui??o de agregado natural pelos agregados reciclados foram preparadas argamassas com tra?o de 1:3 (cimento:agregado), e substitui??o de 20 e 40% do agregado natural. Foram determinadas as caracter?sticas das argamassas no estado fresco (reten??o de ?gua, teor de ar incorporado, densidade de massa) e endurecido (absor??o de ?gua por capilaridade, coeficiente de capilaridade, resist?ncia ? compress?o, resist?ncia ? tra??o na flex?o e massa especifica aparente no estado endurecido). A partir dos resultados obtidos verificou-se, por aplica??o do m?todo de avalia??o multicrit?rios, com a metodologia Analytic Hierarchy Process (AHP), o teor de incorpora??o do agregado reciclado na produ??o de argamassas de uso geral compostas por cimento e areia. Para a aplica??o deste m?todo foram atribu?dos pesos a crit?rios pontuados ligados ao desempenho f?sico e mec?nico das argamassas e crit?rios ambientais ligados ao esgotamento dos recursos naturais e dist?ncia de transporte. O melhor resultado foi encontrado na argamassa com teor de substitui??o de 20% de agregado reciclado misto da unidade municipal de Campinas, mas n?o ? poss?vel observar tend?ncia de obter melhores resultados em argamassas com menor teor de substitui??o, nem t?o pouco exclusivamente por argamassas com agregados reciclados mistos.
385

Viabilidade do uso de RCD proveniente da geração dos concretos convencional e de alta resistência através da utilização do jigue como agente do beneficiamento

Cunha, Michel Gustavo Cardoso January 2017 (has links)
O presente trabalho avaliou a viabilidade do uso de Resíduos de Construção e Demolição (RCD) provenientes da geração de dois traços de concretos distintos. Um Concreto Convencional-CC (traço em massa:1:2,94:3,56; a/c:0,61) utilizando cimento CP IV 32 e outro concreto de Alta Resistência-CAR (traço em massa:1:1,11:2; a/c: 0,22; com adição, aditivo e pó xadrez vermelho) utilizando cimento CP V-ARI. Após 28 dias de cura, 3 corpos de prova de cada traço foram submetidos ao ensaio de resistência a compressão axial apresentando em média para CC 21,02 MPa e para CAR 95,09 MPa. Os materiais de ambos os traços foram cominuídos através de um britador de mandíbula ajustado para granulometria menor que 19,1 mm e retido em 4,75 mm. Com isso, foram realizados ensaios de granulometria de cada traço, e misturados em volumes iguais para o beneficiamento do material. Os primeiros ensaios foram realizados no jigue a ar, porém os resultados apresentados foram insatisfatórios. Para o jigue à água ocorreu uma separação visível de 3 estágios (Topo, Meio e Fundo) Utilizando somente as camadas de topo e fundo, os agregados reciclados de concreto (ARC) foram utilizados para confecção de novos concretos. Os resultados apontaram que a aplicação do jigue à água possibilitou um beneficiamento do material para uso como agregado graúdo. Os ensaios de resistência à compressão, os concretos produzidos com a camada de fundo do agregado reciclado superaram os produzidos com agregado natural. Nos ensaios de módulo de elasticidade, os concretos com o agregado natural exibiram resultados melhores do que os reciclados do topo, porém para os concretos produzidos com os agregados do fundo, os módulos se igualaram aos dos concretos com agregado natural. No ensaio de absorção, o concreto reciclado mostrou uma absorção maior que o concreto natural. Para a carbonatação os concretos com agregados reciclados tiveram melhores resultados. As avaliações dos efeitos foram concludentes para o uso do jigue no beneficiamento do agregado reciclado de concreto (ARC). / The present work evaluates the feasibility of using Construction and Demolition Waste (CDW) generated by two different concrete mixes, one being aconventional concrete-CC (mix:mass: 1:2, 94:3, 56, w/c: 0,61) using CP IV 32, and another being a high strength concrete - CAR (mix:mass: 1:1, 11:2, w/c: 0.22), with the addition of additive and red pigment) using cement CP V-ARI. After 28 days of curing, three test specimens of each concrete were submitted to the resistance test, presenting 21.02 MPa on average for CC and 95.09 Mpa for CAR. The materials of both mixes were comminuted by jaw crusher, and sieved to a particle size range of -19.1 mm + 4.75 mm. With this, granulometry, tests of each concrete were performed and the concretes were mixed in equal volumes for the application of the material processing. The first tests were performed by air jig, but the results were found to be unsatisfactory A visible separation of 3 stages (Top, Middle and Bottom) was achieved by use of water jig. Using only the top and bottom layers, Recycled Concrete Aggregates (RCA) was added for the creation of new concrete. The results indicate that the application of the water jig made it possible to improve the material for use as a large aggregate. For the compressive strength tests, the concretes produced with the bottom layer of the recycled aggregate surpassed those produced with natural aggregate. In the modulus of elasticity tests, concretes with the natural aggregate presented better results than those recycled from the top. For the concretes produced with the bottom aggregates, the modules matched that of the concrete with natural aggregate. In the absorption test the recycled concrete showed a higher absorption than the natural concrete. For carbonation the recycled had better results. An evaluation of the results concludes in favor of the use of water jig for the recycling of concrete aggregates (RCA).
386

Hållbarhetsfrågor vid produktion av An old friend / Corporal Social Responsibility when producing the line An old friend

Lantz, Elin January 2012 (has links)
Jag har under detta arbete undersökt hur företaget MAD ELF ART kan arbeta med miljö och sociala aspekter i produktionen. Min uppgift har varit att lokalisera en materialleverantör och producent som kan arbeta med detta på bästa sätt.Under arbetets gång har jag kontaktat flera materialleverantörer och producenter och undersökt hur de jobbar med dessa aspekter. Samtidigt har jag även fördjupat mig i hur man kan ta hänsyn till miljö och sociala aspekter i produktionen, för att undersöka hur vi bäst kan arbeta med det.Vad jag kommit fram till är att materialvalet är det viktigaste och det som skiljer en produkt från att vara en miljöbov och en fara för människor till miljövänlig. Därför har jag i bilagan presenterat en leverantör och producent av materialet 100% silke som är ekologiskt färgad och handvävd. Silke lämnar inget energi-fotavtryck och går att återvinna. Jag tror och hoppas att framtiden kommer handla om att producera alltmer ekologiskt och samtidigt ta vara på det vi har istället för att producera nytt, detta genom ett återvinningssystem för textilier. Utvecklingen hos stora företag pekar även på att det i framtiden kommer att vara en självklarhet att ha uppförandekoder på fabriker och jobba med CSR. Därför är även det viktigt för MAD ELF ART.I have looked into how MAD ELF ART can work with environmental and social aspects during production. My assignment has been to find a materialsupplier and manufacturer who can work with this in the best way possible.During this work I have contacted several materialsuppliers and manufacturers and examined how they work with these aspects. At the same time I have also looked into how we can deal with social and environmental aspects to find the best way for us to work with this.I have come to the conclusion that the choice of material is the most important and what differs a product from being a danger for the environment and human beings to a environmental friend. Because of that I will present a materialsupplier and manufacturer who can provide the material 100% silk wich is organically dyed and handwoven. Silk leaves no energy-footprint and is recycable. I believe that the future will have more focus on the environment and that we will work with more ecologic materials and instead of producing new products, we will recycle what we have through a recyclingsystem for textiles. The development of big companies also points in the direcetion that it will be natural for all companies to have a Code of conduct and work with Corporal Social Responsility. / Program: Textil produktutveckling med entreprenörs- och affärsinriktning
387

Sulfatna otpornost betona na bazi recikliranog agregata / Sulfate resistance of concrete with recycled aggregate concrete

Bulatović Vesna 24 October 2017 (has links)
<p>U disertaciji su prikazani rezultati sopstvenog eksperimentalnog<br />istraživanja sulfatne otpornosti betona sa recikliranim agregatom.<br />Istraživanje je zasnovano na komparativnoj analizi dve grupe betona koje<br />se razlikuju u krupnom agregatu, a u okviru kojih su varirani dve vrste<br />cementa i dva vodocementna faktora. Sulfatna otpornost je proveravana<br />nakon 3 i 6 meseci boravka u 5% Na2SO4 i u 5% MgSO4. Na očvrslom betonu<br />ispitivani su kapilarno upijanje vode, promena dužine uzoraka, čvrstoća<br />pri pritisku i urađene su mikrostrukturne analize: MIP, SEM, BSE/EDS,<br />XRD i FTIR. Istaknuto je da se primenom krupnog agregata od recikliranog<br />betona i veziva odgovarajućeg mineraloškog sastava mogu dobiti<br />konstrukcijski betoni, odnosno betoni sa zadovoljavajućim mehaničkim<br />karakteristikama, ali i sa zadovoljavajućom trajnošću sa aspekta<br />sulfatne korozije.</p> / <p>This paper presents the experimental research results of the sulphate resistance of<br />concrete with recycled aggregate. The research is based on a comparative analysis of<br />two groups of concrete that differ in coarse aggregate types. Within these two concrete<br />groups, two types of cement of the same class and two water/cement ratios have been<br />varied. Sulphate resistance was examined after 3 and 6 months of immersion in 5%<br />Na2SO4 and 5% MgSO4. Capillary water absorption, sample length change and<br />compressive strength were studied in hardened concrete and the following<br />microstructural analyzes were performed: MIP, SEM, BSE/EDS, XRD and FTIR. It has<br />been found that structural concrete with apppropriate mechanical properties as well as<br />with satisfactory durability from the aspect of sulphate corrosion can be obtained by<br />combination of a coarse recycled concrete aggregate and a binder of an appropriate<br />mineralogical composition.</p>
388

Анализа примене отпадних и рециклираних материјала за израду порозног бетонског коловоза / Analiza primene otpadnih i recikliranih materijala za izradu poroznog betonskog kolovoza / Analysis of the application of waste and recycled materials for the production of pervious concrete pavements

Šešlija Miloš 24 September 2018 (has links)
<p>У дисертацији су анализиране мешавине за израду порозног бетонског коловоза. Пројектовано је укупно 12 различитих врста мешавина. За справљање бетонских мешавина коришћене су фракције природног и рециклираног агрегата. Електрофилтерски пепео, који је отпадни материјал из термоелектрана, коришћен је као минерални додатак, којим је замењен део цемента. Справљено је шест мешавина са рециклираним агрегатом и шест мешавина са природним агрегатом. Лабораторијска испитивања су обухватила испитивање чврстоће при притиску бетона након: 7, 28, 56 и 84 дана, чврстоће при савијању (након 28, 56 и 84 дана), модул еластичности (статички и динамички), отпорност према хабању, коефицијент водопропустљивости и порозност. Добијени резултати потврдили су постављене хипотезе да је са рециклираним агрегатом и електрофилтерским пепелом могуће пројектовати и извести порозни бетонски коловоз.</p> / <p>U disertaciji su analizirane mešavine za izradu poroznog betonskog kolovoza. Projektovano je ukupno 12 različitih vrsta mešavina. Za spravljanje betonskih mešavina korišćene su frakcije prirodnog i recikliranog agregata. Elektrofilterski pepeo, koji je otpadni materijal iz termoelektrana, korišćen je kao mineralni dodatak, kojim je zamenjen deo cementa. Spravljeno je šest mešavina sa recikliranim agregatom i šest mešavina sa prirodnim agregatom. Laboratorijska ispitivanja su obuhvatila ispitivanje čvrstoće pri pritisku betona nakon: 7, 28, 56 i 84 dana, čvrstoće pri savijanju (nakon 28, 56 i 84 dana), modul elastičnosti (statički i dinamički), otpornost prema habanju, koeficijent vodopropustljivosti i poroznost. Dobijeni rezultati potvrdili su postavljene hipoteze da je sa recikliranim agregatom i elektrofilterskim pepelom moguće projektovati i izvesti porozni betonski kolovoz.</p> / <p>In the dissertation, mixtures for the production of pervious concrete pavements are analyzed. The project has a total of 12 different types of mixtures. For the preparation of concrete mixtures, the fractions of natural and recycled aggregates were used. Fly ash, which is a waste material from thermal power plants, was used as a mineral supplement, which replaced a part of cement. Six mixtures with a recycled aggregate and six mixtures with a natural aggregate were collected. Laboratory tests included: compressive strength after 7, 28, 56 and 84 days, felxural strength (after 28, 56 and 84 days), modulus of elasticity (static and dynamic), abrasion, permeability and porosity. The obtained results confirmed the hypotheses that it is possible to design and execute a previous concrete pavement with a recycled aggregate and fly ash.</p>
389

Avaliação da influência da origem e do tratamento dos agregados reciclados de resíduos de construção e demolição no desempenho mecânico do concreto estrutural. / Evaluate the influence of origin and processing of recycled aggregates from construction and demolition waste on the mechanical performance of structural concrete.

Moreira, Lucia Hiromi Higa 05 November 2010 (has links)
A cadeia da construção civil é uma grande causadora de impactos ambientais, pois além do alto consumo de recursos naturais gera também grandes quantidades de resíduos. Isto traz elevados custos à sociedade pela necessidade de remoção e destinação dos resíduos, normalmente depositados em aterros. A reciclagem tem sido uma alternativa para redução do volume de resíduos finais. Estudos utilizando agregados reciclados de Resíduos de Construção e Demolição (RCD) para a produção de concreto têm sido realizados por vários pesquisadores indicando viabilidade técnica da sua aplicação. No entanto, há dúvidas que dificultam a implementação do uso de resíduos reciclados dada a grande variabilidade das suas propriedades devido à variação de sua constituição que é muito influenciada pela origem dos mesmos. Assim, alguns tratamentos são propostos com a intenção de otimizar o desempenho do concreto produzido com estes agregados reciclados. A presente dissertação tem como objetivo avaliar a influência dessas variabilidades dos agregados de RCD reciclados nas propriedades do concreto estrutural. Esses agregados foram provenientes das cidades de Macaé e São Paulo, ambos submetidos aos mesmos tipos de tratamento: (a) britagem e (b) britagem e separação densitária (jigue), atendendo a mesma faixa granulométrica de -19+4,8 mm. No programa experimental, foi utilizada a metodologia de dosagem convencional para a avaliação do comportamento mecânico do concreto reciclado. Neste estudo, os agregados foram utilizados sem pré-saturação, o que possibilitou o preenchimento de parte dos poros dos agregados pela pasta de cimento. Tal procedimento contribuiu para uma menor diferença relativa de desempenho do concreto convencional em relação ao produzido com agregados reciclados, principalmente para os concretos com maior relação água/cimento. Foram analisados os resultados de resistência à compressão, resistência à tração por compressão diametral, módulo de elasticidade, absorção de água, índice Binder Intensity e ensaio de ultra-som. Comprovou-se que a porosidade dos agregados é o fator principal de influência no comportamento do concreto. Já a origem dos agregados foi um fator secundário dado que os mesmos apresentavam diferentes porosidades em função da cidade onde foram obtidos. A separação densitária possibilitou a aproximação do comportamento dos agregados de diferentes origens por aproximar a porosidade dos mesmos. / The civil construction industry is a great producer of environment impacts. It also generates great amounts of residues, further the high consumption of natural resources. This fact brings high costs to society due to the need of residues removing and disposal, which typically occurs in landfills. Recycling has been an alternative to reduce the volume of residues. Studies using recycled aggregates from Construction and Demolition Waste (CDW) to produce concrete have been carried out by several researchers, indicating that is technically feasible in terms of application. However, there are questions that turns difficult the implementation of the use of recycled residues, due to the great variability of their properties as a result of the variation of their constitution, which is strongly influenced by their origin. Thus, a few treatments are proposed, aiming at optimizing the performance of these recycled aggregates to produce concrete. The present work aims at assessing the influence of the recycled CDW aggregates on the properties of structural concrete. These aggregates originated from the cities of Macaé and São Paulo, and both were submitted to the same type of treatment: (a) crushing and (b) crushing and density separation (jig), complying with the same granulometric range of -19+4.8 mm. The conventional mix design methodology was used in the experimental program to assess the concrete behavior and the influence of the recycled material. The aggregates were used in this study without being pre-saturated, which allowed filling up part the pores of the aggregates with cement paste. Such procedure contributed for a smaller relative difference on the performance of the conventional concrete and that one produced with recycled aggregates, especially the concrete with a higher water/cement ratio. The compressive strength, split tensile strength, elastic modulus, water absorption, Binder Intensity index and measuring of ultrasonic testing were analyzed. The porosity of the aggregate was proved to be a prevalent factor influencing the behavior of the concrete. The origin of the aggregates was a secondary factor because they had different porosities according to the city where they were obtained. The density separation allowed the reduction of the difference in behavior between the concretes produced with aggregates from different origins by approaching their porosity.
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Primena pepela nastalog sagorevanjem žetvenih ostataka kao mineralnog dodatka u cementnim kompozitima / Application of biomass ash, generated by combustion of harvest residues, as a mineral additive in cement composites

Šupić Slobodan 11 October 2019 (has links)
<p>U disertaciji su prikazani rezultati sopstvenog eksperimentalnog istraživanja mogućnosti primjene biopepela, nastalog sagorjevanjem žetvenih ostataka, kao mineralnog dodatka u cementnim kompozitima: malterima i betonima. Istraživanje je zasnovano na komparativnoj analizi 27 vrsta maltera u kojima je varirana vrsta biopepela i vrsta sitnozrnog agregata i 12 vrsta betona koje se razlikuju u vrsti veziva i u krupnom agregatu. Na očvrslom malteru su ispitani: konzistencija, čvrstoća pri pritisku i kapilarno upijanje vode, a na očvrslom betonu ispitivani su kapilarno upijanje vode, skupljanje pri sušenju, čvrstoća pri pritisku, dinamički modul elastičnosti, otpornost na habanje, vodonepropustljivost i čvrstoća na savijanje. Istaknuto je da se primjenom biopepela kao zamjene dijela cementa mogu dobiti konstrukcijski malteri i betoni, odnosno betoni sa zadovoljavajućim fizičkim i mehaničkim karakteristikama.</p> / <p>The dissertation presents the results of an own experimental research on the possibility of using biomass ash as a mineral additive in cement composites: mortar and concrete. The research is based on a comparative analysis of 27 types of mortars in which the type of biomass ash and the type of fine-grained aggregate were varied, as well as 12 types of concrete that differ in the type of binder and coarse aggregate. Following properties were tested on hardened mortars: consistency, compressive strength and capillary water absorption, and on hardened concrete: capillary water absorption, drying shrinkage, compressive strength, dinamic modulus of elasticity, wear resistance, waterpermeability and flexural strength. It was pointed out that biomass ash can be used as a replacement of a part of cement, thereby obtaining satisfactory physical and mechanical characteristics.</p>

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