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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.
51

Självkompakterande betong : Ytjämnhet utan efterbehandling / Self-Compacting Concrete : Flat surface without after-treatment

Elofsson, Andreas, Hallin, Mikael January 2006 (has links)
Betonggjutning är ett tungt moment inom byggproduktion och entreprenörer har länge använt betong med flyttillsats för att få en mer lättarbetad betong. Ändå har det krävts långa arbetspass och många tungarbetade moment. Efter lasernivellering, vibrering, slodning och glättning har man kunnat uppnå en yta som nästan är helt jämn. Dock ej så jämn att avjämningsmassa kunnat elimineras för att inte få sviktande parkett eller buktande plastmattor. Självkompakterande betong (SKB), eller vibreringsfri betong som man först kallade den, forskades fram på 80-talet i Japan och dök upp i Sverige i slutet på 90-talet. Det är en betong som innehåller en flyttillsats och en så kallad filler vars gemensamma egenskaper ger en betong som har bibehållen homogenitet samtidigt som den fyller ut formen och omsluter armering endast genom gravitationskraften. SKB är ca 10-15 % dyrare än traditionell betong men har motiverats med framförallt minskad produktionstid, färre betongarbetare och bättre arbetsmiljö. Eftersom SKB mer eller mindre är flytande så blir jämnheten mycket god. Erfarenhetsmässigt har ytorna blivit i det närmaste perfekta efter lasernivellering, slodning och torrslipning. Trots stora konstaterade arbetsmiljövinster och vetskapen om den goda ytjämnheten har AB Färdig Betong i Karlstad endast levererat SKB till 8 projekt sedan 1997. Examensarbetets syfte är att fastställa om SKB kan motiveras baserat på den goda ytjämnhet som kan uppnås redan efter gjutning jämfört med normalpresterande betong (NPB). Examensarbetet har utförts i samarbete med Skanska Sverige AB i Karlstad, som under våren 2006 genomförde två projekt med SKB. Mätningar av ytor med SKB gjordes på Färjstad i Karlstad och mätningar av referensytor med NPB gjordes i Karlstad med omnejd. Mätningarna kompletteras med intervjuer i form av erfarenhetsåterföring från dem som tillverkat, levererat, mottagit, gjutit och efterbehandlat betongtypen. De krav på ytjämnhet av platsgjuten betong som generellt tillämpas återfinns i Hus AMA 98 och definieras som buktighet, lutning och nivåskillnad. Resultaten från mätningarna bedömdes i enlighet med Hus AMA 98, därefter har betongtypernas mätvärden analyserats och jämförts. Utifrån resultaten har bland annat följande slutsatser kunnat konstateras: Självkompakterande betong kan vid rätt handhavande ge en yta som uppfyller kraven enligt Hus AMA’s krav för undergolv i klass B utan varken vibrering, slipning eller efterbehandling. Användandet av SKB i större bostadsprojekt skapar stora förutsättningar för lägre totalekonomi jämfört med användandet av NPB. Detta baseras huvudsakligen på minskat behov av arbetskraft vid gjutning och efterbehandling av den gjutna ytan. De bekräftade möjligheterna för förbättrad ytkvalitet redan efter gjutning kommer i framtiden innebära att fler entreprenörer väljer SKB. / Concrete moulding is a heavy moment in the building process and for a long time contractors have used an admixture to create a concrete that is easier to handle. However many hours of work and heavy moments has been required. After laser levelling, vibrating, screeding and troweling a surface that is almost flat has been obtained. Yet not flat enough to eliminate floor levelling and thereby avoiding bending parquet flooring or curved plastic flooring. Self-compacting concrete (SCC), or vibrating free concrete as it was named in the beginning, was developed in the eighties in Japan and showed up in Sweden in the late nineties. It is a concrete that contains an admixture and filler that together makes the concrete flow under its own weight, completely filling the formwork and achieving full compaction, even in the presence of congested reinforcement. SCC is approximately 10-15 % more expensive than traditional concrete but is motivated with faster construction times, fewer workers and an improved work environment. Since SCC just about flows the resulting surface becomes almost perfect. Experience shows that surfaces are nearly perfect after laser levelling, screeding and dry smoothing. Despite the advantages of the flat surfaces and the established improvement on the work environment, AB Färdig Betong in Karlstad, Sweden has only delivered SCC to eight projects since 1997. The aim of this degree thesis is to determine if SCC can be motivated based on the flat surfaces that can be obtained after moulding compared to traditional concrete. The degree thesis has been performed in cooperation with Skanska Sverige AB in Karlstad, Sweden at their two projects with SCC in spring 2006. The measurement of SCC surfaces was made in Färjestad, Karlstad and reference measurements of traditional concrete was made in Karlstad and surroundings. The measurement have been complemented with interviews that present experience of producing, delivering, receiving, moulding and after treating SCC. The requirements for on site moulding concrete surfaces that are to be followed are found in Hus AMA 98 and is defined as curve, rake and level variance. The result from the measurements are judged on the basis of the requirements. Conclusions Correctly performed SCC can create a surface that fulfils the requirements in Hus AMA 98 for a class B floor. The use of SCC in larger housing constructions makes conditions for a lower total cost. This is based principally on fewer workers, faster construction times and less after treatment of the moulded surfaces. The confirmed possibilities of improved surfaces after moulding should mean that more contractors will use SCC in the future.
52

Self-compacting Concrete With High Volumes Of Fly Ash

Sahmaran, Mustafa 01 January 2006 (has links) (PDF)
In this investigation, SCCs were prepared by keeping the total mass of cementitious materials (cement and fly ash) constant at 500 kg/m3, in which 30, 40, 50, 60, and 70% of cement, by weight, was replaced by the high-lime and low-lime fly ash. For comparison, a control SCC mixture without any fly ash was also produced. The fresh properties of the SCCs were observed through, slump flow time and diameter, V-funnel flow time, L-box height ratio, U-box height difference, segregation ratio and the rheological parameters (relative yield stress and relative plastic viscosity). Relations between workability and rheological parameters were sought. Setting times and temperature rise of the SCC were also determined. The hardened properties included the compressive strength, split tensile strength, drying shrinkage and permeation properties (absorption, sorptivity and rapid chloride permeability tests) up to 360 days. The results obtained indicated that it is possible to produce SCC with a 70% of cement replacement by both types of fly ash. The use of high volumes of fly ash in SCC not only improved the workability and permeability properties but also made it possible to produce concretes between 33-40 MPa compressive strength at 28 days.
53

A influência do patamar de cura térmica sobre a resistência dos concretos auto-adensáveis elaborados com diferentes tipos de cimento : avaliação pelo método da maturidade /

Santos, Liane Ferreira dos. January 2010 (has links)
Orientador: Mônica Pinto Barbosa / Banca: Cassio Roberto Macedo Maia / Banca: Oswaldo Cascudo Matos / Resumo: O concreto auto-adensável (CAA) é um material que representa um dos maiores avanços na tecnologia do concreto das últimas décadas. O desenvolvimento do CAA propiciou eficiência e melhora nas condições de trabalho em canteiro de obras e na indústria de pré-moldados. Do ponto de vista reológico, o CAA é uma mistura fluida que proporciona diferenças de comportamento quando comparado ao concreto convencional. Neste contexto, a proposta desta pesquisa foi estudar, num primeiro plano, as características reológicas nas fases de pasta, argamassa e concreto do CAA no estado fresco e seu comportamento no estado endurecido. Para isso, optouse por empregar a metodologia de Repette e Melo (2005), que considera a resistência à compressão como ponto de partida para a composição do traço do CAA e que estuda os aspectos reológicos envolvidos nas diferentes fases de sua dosagem. Os materiais empregados para estudo de dosagem foram o fíler basáltico como adição, areia média, brita 19 mm, aditivo superplastificante e dois tipos de cimento. Foram elaborados dois concretos, com cimentos distintos, ambos com mesma classe de resistência igual a 40 MPa. Num segundo plano, foi realizado um estudo da avaliação da resistência à compressão desses concretos quando submetidos à cura térmica a vapor, variando-se as temperaturas de cura (entre 65oC e 80oC), assim como o patamar isotérmico de cura em 4 h,6 h e 8 h para cada temperatura. A avaliação das propriedades mecânicas dos concretos foi realizada empregando o Método da Maturidade. No emprego da maturidade foram utilizados as funções de Nurse e Saul e a proposta por Freiesleben-Hansen e Pedersen (FHP). As análises comparativas foram realizadas em função do tipo de cimento empregado, temperatura de cura e tempo de patamar isotérmico / Abstract: The self-compacting concrete (SCC) is a material that represents one of the greatest advances in concrete technology in recent decades. The development of SCC has resulted in improved efficiency and working conditions at the construction site and the precast industry. Rheological point of view, the SCC is a fluid mix that provides behavior differences when compared to conventional concrete. In this context, the proposal of this research was to study, in the foreground, the rheological phases of paste, mortar and concrete of SCC in the fresh state and its behavior in the hardened state. For this, we chose to employ the methodology Repette e Melo (2005), which considers the compressive strength as a starting point for the composition of the trace of SCC and studying the rheological aspects involved in the different stages of their dosage. The materials used to study the dosage was basalt fillers such as addition, medium sand, gravel 19 mm, superplasticizer additive and two types of cement. We prepared two concretes with different cements, both with the same strength class of 40 MPa. In the background, a study assessing the compressive strength of concrete when subjected to steam curing, varying the curing temperatures (between 65oC and 80oC) as well as the level of isothermal cure at 4 h, 6 h and 8 h for each temperature. The evaluation of mechanical properties of concrete was carried out using the Maturity Method. Employment of maturity was used to Nurse e Saul function, as well as function proposed by Freiesleben-Hansen and Pedersen (FHP). Comparative analysis were performed according to the type of cement used, curing temperature and isothermal plateau / Mestre
54

Behaviour of continuously supported self-compacting concrete deep beams

Khatab, Mahmoud A. T. January 2016 (has links)
The present research is conducted to investigate the structural behaviour of continuously supported deep beams made with SCC. A series of tests on eight reinforced two-span continuous deep beams made with SCC was performed. The main parameters investigated were the shear span-to-depth ratio, the amount and configuration of web reinforcement and the main longitudinal reinforcement ratio. All beams failed due to a major diagonal crack formed between the applied mid-span load and the intermediate support separating the beam into two blocks: the first one rotated around the end support leaving the rest of the beam fixed on the other two supports. The amount and configuration of web reinforcement had a major effect in controlling the shear capacity of SCC continuous deep beams. The shear provisions of the ACI 318M-11 reasonably predicted the load capacity of SCC continuous deep beams. The strut-and-tie model recommended by different design codes showed conservative results for all SCC continuous deep beams. The ACI Building Code (ACI 318M-11) predictions were more accurate than those of the EC2 and Canadian Code (CSA23.3-04). The proposed effectiveness factor equations for the strut-and-tie model showed accurate predictions compared to the experimental results. The different equations of the effectiveness factor used in upper-bound analysis can reasonably be applied to the prediction of the load capacity of continuously supported SCC deep beams although they were proposed for normal concrete (NC). The proposed three dimensional FE model accurately predicted the failure modes, the load capacity and the load-deflection response of the beams tested.
55

Obtenção do concreto autoadensável utilizando resíduo do beneficiamento do mármore e granito e estudo de propriedades mecânicas / Obtaining of the Self Compacting-Concrete using Residue of the Improvement of the Marble and Granite and Study of Mechanical Properties

Lisbôa, Edvaldo Monteiro 27 December 2004 (has links)
The Self-Compacting Concrete (SCC) it needs of the high amount of fine in yo ur composition to assist your properties in the fresh state. In the context of the fine materials if show the Residue of the Improvement of the Marble and Granite (RBMG), which was chosen to compose the dosagem of CAA in that research. This was a form of contributing with the technological progress and maintainable development of the concrete. Using Gomes' Methodology (2002) for obtaining of SCC, the study of the paste was developed through the rehearsals in the Cone of Marsh and in the Mini-slump and the study of the mortar using the rehearsals in the Cone of Marsh and in the cone log of the consistence table, all, in the sense of obtaining the percentile great of superplasticizer and an appropriate amount of RBMG in the composition of the mixture. Starting from parameters obtained in the study of the paste and mortar was given segment to a practical application of completion of premolded pieces, without the use of any type of mechanical vibration, with self-compacting mortar. Soon after, through the study of the composition of the granular skeleton it was obtained the great relationship among the small and great aggregate. The study of the concrete was developed using the rehearsals of Slump-flow, V Funnel, L Box and U Pipe, for the tests of your properties in the fresh state, such as: filling ability, passing ability and segregation resistance. In this study they were obtained two Self Compacting Concrete, a just using RBMG and other with 3% of sílica fume; in this it was verified some improvements in the viscosity and in the cohesion of the mixture. For both concretes they were moulded cylindrical specimens of 10cm x 20cm and 15cm x 30cm for study of the resistance to the compression to the 7 days and the 28 days; module of static deformation and resistance to the traction in the diametrical compression to the 28 days. The results of the accomplished rehearsals indicated for the technical viability of the use of RBMG in the production of SCC. / O Concreto Auto-Adensável (CAA) necessita de uma alta quantidade de finos em sua composição para atender suas propriedades no estado fresco. No contexto dos materiais finos se apresenta o Resíduo do Beneficiamento do Mármore e Granito (RBMG), o qual foi escolhido para compor a dosagem do CAA nessa pesquisa. Esta foi uma forma de contribuir com o avanço tecnológico e desenvolvimento sustentável do concreto. Utilizando a Metodologia de Gomes (2002) para obtenção do CAA, foi desenvolvido o estudo da pasta através dos ensaios no Cone de Marsh e no Mini-slump e o estudo da argamassa usando os ensaios no Cone de Marsh e no Tronco de cone da mesa de consistência, todos, no sentido de se obter o percentual ótimo de superplastificante e uma quantidade adequada do RBMG na composição da mistura. A partir de parâmetros obtidos no estudo da pasta e argamassa foi dado segmento a uma aplicação prática de preenchimento de peças pré-moldadas, sem a utilização de nenhum tipo de vibração mecânica, com argamassa auto-adensável. Em seguida, através do estudo da composição do esqueleto granular foi obtida a relação ótima entre o agregado miúdo e graúdo. O estudo do concreto foi desenvolvido utilizando os ensaios de Espalhamento, Funil V, Caixa L e Tubo em U, para os testes de suas propriedades no estado fresco, tais como: capacidade de preenchimento, capacidade de passagem por obstáculos e resistência à segregação. Neste estudo foram obtidos dois Concretos Auto- Adensáveis, um usando apenas o RBMG e outro com 3% de sílica ativa; neste foi verificado algumas melhoras na viscosidade e na coesão da mistura. Para ambos concretos foram moldados corpos-de-prova cilíndricos de 10cm x 20cm e 15cm x 30cm para estudo da resistência à compressão aos 7 dias e aos 28 dias; módulo de deformação estática e resistência à tração na compressão diametral aos 28 dias. Os resultados dos ensaios realizados indicaram pela viabilidade técnica da utilização do RBMG na produção de CAA.
56

Contribuição ao estudo de propriedades do concreto autoadensável visando sua aplicação em elementos estruturais

Cavalcanti, Diogo Jatobá de Holanda 02 June 2006 (has links)
The Self-compacting concrete (SCC) is already in use in several countries and represents one of the biggest advances in concrete technology in the last decades. Its name is related to the growth of productivity, the improvement on constructive environment and the contribution of sustainable concrete technology that is characterized as an environment-friendly material, obtained with high volumes of industrial waste. As its development is characterized mainly by its properties in its fresh stage, the studies of its mechanical properties, such as compressive strength (fc), diametral compressive strength or traction strength (ft), and the modulus of elasticity (Ec), as its evolution and relations between each other have been little developed. The c.p s molding procedures with SCC is only modified, since the self-compacting concrete doesn t need any vibration. Within that focus, a SCC added with marble and the filler RSMG is produced, and its mechanical properties are determined and compared with a conventional concrete of reference and others SCC. The c.p. molding is also analyzed in order to verify its compactibility.The study prove that the best way to fill the mold, is similar to the one used for the reference conventional concrete, except the process of vibration. Equations of the evolution of fc and relations between fc x ft e fc x Ec to SCC are also accomplished and compared with the ones presented for conventional concrete. The results proved that the equations used of conventional concrete are accepted for the SCC. / Fundação de Amparo a Pesquisa do Estado de Alagoas / O concreto auto-adensável (CAA) já é utilizado em vários países e representa um dos maiores avanços na tecnologia do concreto das últimas décadas. Seu nome está relacionado com o aumento na produtividade, melhora do ambiente construtivo e contribuição da tecnologia sustentável do concreto, sendo caracterizado como um material ambientalmente amigável, e podendo ser obtido com altos volumes de resíduos industriais. Como seu desempenho está mais associado às suas propriedades no estado fresco, estudos de propriedades mecânicas, como: resistências à compressão (fc) e à tração (ft) e o módulo de deformação longitudinal (Ec), assim como sua evolução e relações entre as mesmas, têm sido pouco desenvolvidos. Dos procedimentos que antecedem a determinação das propriedades mecânicas do concreto, a moldagem dos c.p. com CAA é a única modificada, pois, o adensamento do concreto não necessita de vibração. Dentro deste enfoque, um concreto auto-adensável com a adição mineral do resíduo de serragem de mármore e granito (RSMG) é produzido, e suas propriedades mecânicas são determinadas e comparadas com as de um concreto convencional e de outros CAA. Diferentes métodos de moldagem em c.p cilíndricos com o CAA também são analisados, a fim de verificar sua auto-adensabilidade. O estudo comprova que a melhor forma de preenchimento dos moldes com CAA é semelhante ao adotado para concretos convencionais, a menos do processo de vibração. Equações de evolução de fc e relações fc x ft e fc x Ec para CAA também são obtidas e comparadas com as apresentadas para concreto convencional. Os resultados comprovam que as relações usadas para concreto convencional são aceitas para o CAA.
57

Caracterização e composição de agregados reciclados para obtenção de concreto autoadensável leve reciclado com fins estruturais / Characterization and composition of recycled aggregates to obtain recycled lightweight self-compacting concrete for structural purposes

Mendes, Everton Luiz da Silva 09 December 2016 (has links)
The use of recycled aggregate in the production of self-compactig concrete (SCC) is relatively recent. Few studies have been developed, but, there are numerous advantages in its application. The recycled lightweight self-compacting concrete (RLSCC) offers several advantages of SCC, due to the self-compacting properties, it absorbs construction residues, in the use as recycled aggregates, and the lightness due to the smaller specific mass of the recycled aggregates, it promotes the reduction of the loads due to the own weight . However, studies carried out in concrete with recycled aggregates (RA) have shown to be very complex due to the characteristics of these aggregates, such as: high porosity, high water absorption, irregular shape, rough surface, etc. These characteristics tend to lead to mixtures with less workable and lower mechanical strength. In this way, the study had as objective to obtaining the RLSCC, separate the process in two steps: aggregates and mortar. Where, the characterization of the RA is the way to understand its characteristics and the limitations that it will impose in the mixture of concrete. The study of mortars, to verify a composition with the best parameters of fluidity and rheological, since the difficulty faced by researchers in obtaining workable mixtures. Thus, it was verified that the standardized characterization methodologies, for natural aggregates, face some difficulties in their application in recycled aggregates, rendering them inefficient. The characteristics of the recycled aggregate could be attenuated with a composition study, reaching very workable mortars, with low yield stress and moderate viscosity. The SCC was obtained through a study of maximum content of recycled coarse aggregate, through concrete tests. The obtained concrete presented compression strength of 30 MPa and apparent specific mass of 2000 kg/m³, classifying it as concrete of structural application and light. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A utilização de agregado reciclado na produção de concreto autoadensável (CAA) é relativamente recente. Poucos estudos têm sido desenvolvidos, mas, observam-se inúmeras vantagens em sua aplicação. O concreto autoadensável leve reciclado (CAALR) oferece diversas vantagens do CAA, devido às propriedades de autoadensabilidade, absorve resíduos de construções, na utilização como agregados reciclados, e a leveza devido a menor massa específica dos agregados reciclados, promove a redução das cargas devido ao peso próprio. No entanto, estudos realizados em concreto com agregados reciclados (AGR), têm se mostrado muito complexos devido às características destes agregados, como: elevada porosidade, alto teor de absorção de água, forma irregular, superfície rugosa, etc. Características estas que tendem a conduzir a misturas pouco trabalháveis e de resistência mecânica inferior. Desta forma, o estudo teve como objetivo a obtenção CAALR, separando o processo em duas etapas: agregados e argamassa. Onde, a caracterização do AGR é o meio para o entendimento de suas características e das limitações que ele irá impor na mistura de concreto. Já o estudo de argamassa, o objetivo foi verificar uma composição com os melhores parâmetros de fluidez e reológicos, visto as dificuldades enfrentadas por pesquisadores em obter-se misturas trabalháveis. Assim, verificou-se que as metodologias de caracterização normatizadas, para agregados naturais, enfrentam algumas dificuldades na sua aplicação em agregados reciclados, tornando-as pouco eficientes. As características do agregado reciclado miúdo puderam ser atenuadas com um estudo de composição, chegando a argamassas muito trabalháveis, com baixa tensão de escoamento e viscosidade moderada. A obtenção do CAA foi possível, através de um estudo de teor máximo de agregado reciclado graúdo, através de ensaios em concreto. O concreto obtido apresentou resistência de 30 MPa e massa específica aparente de 2000 kg/m³, classificando-o como concreto de aplicação estrutural e leve.
58

Vers une utilisation rationnelle des métakaolins flash : application aux bétons / A rational use of the flash metakaolin : concrete applications

Bucher, Raphaël 10 June 2015 (has links)
L'objectif de ce travail est de contribuer à la valorisation du métakaolin en substitution du ciment dans les matrices cimentaires en levant certains verrous scientifiques. En effet l'utilisation d'additions minérales modifie les propriétés des bétons, que cela soit à l'état frais, à l'état durcissant ou à l'état durci. A l'état frais, la rhéologie a été étudiée avec l'adaptation et l'application d'une méthode de formulation pour béton auto-plaçant. Cette application a été développée jusqu'à l'échelle industrielle. A l'état durcissant, la phase d'hydratation a été étudiée en s'attardant particulièrement sur l'effet de la nature du ciment substitué sur la réactivité du métakaolin. Enfin à l'état durci deux caractéristiques de durabilité ont été explorées, à savoir l'effet du métakaolin sur la carbonatation dans une première partie, puis sur la diffusion des chlorures dans une deuxième partie. / The objective of the present thesis was to promote the use of metakaolin as substitute for cement in cementitious matrix by unlocking several scientific challenges. The use of mineral additions modifies the properties of concrete in the fresh state, the hardening state and the durability state. In the fresh state, rheology was studied by adapting a formulation method for self-compacting concretes. This application was then further developed to be used at an industrial scale. In the hardening state, the hydration phases were analysed with a focus on the effect of the cement nature on the metakaolin reactivity. Finally in the durability state, two particular features were studied:1) the metakaolin effect on the carbonation kinetic and 2) the effect of the metakaolin on the chloride diffusion.
59

Concreto auto-adensável utilizando resíduos de caulim

Diniz, Marcelo Andrade 30 September 2010 (has links)
Made available in DSpace on 2015-05-14T12:09:06Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2185418 bytes, checksum: 8edee78b6cc4067e1c81e1ad8e74a457 (MD5) Previous issue date: 2010-09-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Self-compacting concrete (SCC), considered one of the greatest advances in concrete technology, is characterized by its special capacity of filling ability, passing ability and resistance to segregation by the action of its own weight without the presence of other external forces. Taking into consideration the numerous cities and their industries that have caused a considerable increase in the production of solid waste, including industrial waste in SCC has brought about significant environmental benefits. This study aimed to develop a SCC with inclusion of waste from the manufacturing of kaolin, specifically from what is called birra and borra . The most common producers of SCC used limestone filler. In the production of SCC the mix-design method Tutikian (2007) and Gomes (2002) were used as a base, the Marsh funnel and miniature slump tests for paste composition and the compactability test of materials for the fabrication of granulometric skeletons. In order to evaluate the properties of SCC in fresh state tests, the slump flow test, slump flow test T50cm, V-funnel, V-funnel 5min, L-box, U-box and J-ring were used. The possibility of using waste from the kaolin beneficiation in a SCC was proven, where the borra was used as fine material and birra as a replacement for aggregates. In the hardened state, testing of compressive strength were carried out on the 7th and 28th days, resulting in resistance rate of approximately 20 to 40MPa. / O concreto auto-adensável (CAA), considerado como um dos maiores avanços na tecnologia do concreto, é caracterizado por suas capacidades especiais de preenchimento, habilidade de passagem e resistência à segregação pela ação do seu próprio peso sem que existam outras forças externas. Diante do panorama em que as cidades e suas indústrias têm provocado um considerável aumento na produção dos resíduos sólidos, incluir resíduos industriais ao CAA traz benefícios ambientais significativos. Assim, este trabalho teve por objetivo desenvolver um CAA com inserção de resíduos provenientes da fabricação de caulim, mais especificamente a birra e a borra. No CAA de referência foi utilizado o fíler calcário. Na confecção do CAA foram utilizados como base os métodos de dosagem Tutikian (2007) e Gomes (2002), sendo realizados os testes do Funil de Marsh e mini-cone para composição da pasta e os testes de compacidade dos materiais para confecção dos esqueletos granulométricos. Para avaliar as propriedades do CAA no estado fresco foram executados os testes do espalhamento, espalhamento T50cm, funil-V, funil V 5min, caixa-L, caixa-U e anel-J. Foi constatada a possibilidade de utilizar resíduos provenientes do beneficiamento de caulim em um CAA, a borra como material fino e a birra em substituição de parte dos agregados. No estado endurecido, foram executados testes de resistência à compressão aos 7 e 28 dias, obtendo resistências na faixa aproximada de 20 MPa a 40 MPa.
60

Análise experimental de pilares de concreto armado, com carga excêntrica, reforçados com chumbadores e concreto autoadensável (CAA) / Experimental analysis of reinforced concrete columns, under eccentric load, reinforced with wedge bolts and self compacting concrete (SCC)

Virgens, Jeovan Pereira das 16 October 2015 (has links)
Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-03-31T19:38:48Z No. of bitstreams: 2 Dissertação - Jeovan Pereira das Virgens - 2015.pdf: 10009095 bytes, checksum: a8f3d2a6914adbb0c7cdcf49732ffc57 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-04T11:45:04Z (GMT) No. of bitstreams: 2 Dissertação - Jeovan Pereira das Virgens - 2015.pdf: 10009095 bytes, checksum: a8f3d2a6914adbb0c7cdcf49732ffc57 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-04-04T11:45:04Z (GMT). No. of bitstreams: 2 Dissertação - Jeovan Pereira das Virgens - 2015.pdf: 10009095 bytes, checksum: a8f3d2a6914adbb0c7cdcf49732ffc57 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-10-16 / This paper presents the experimental study of reinforcement concrete columns reinforced with wedge bolts and a 35 mm self compacting concrete jacket at the most compressed face. Nine columns with a 2000 mm height subjected to flexure and bending with initial eccentricity of 60 mm, named as: original column (Po) with a cross section of 120 mm x 250 mm; reference column (Pref) with a cross section of 155 mm x 250 mm and seven columns with a initial cross section of 120 mm x 250 mm, and later reinforced by the addition of 35 mm reinforcing layer, and various configurations of wedge bolts at its most compressed face. Except for the original column (Po), the columns were submitted to a 42.5 mm load eccentricity due to the attached concrete layer at the compressed face. Although failure of the wedge bolts did not accour, it was not possible to prevent detachment of the reinforcing layer. The results indicate that it is possible to structural rehabilitate reinforce concrete columns with the use of the strengthening methodology used in this research, resulting in average load capacity gains of 3,71 times compared to original column load (Po). / O presente trabalho apresenta o estudo experimental de pilares de concreto armado reforçados com parafusos chumbadores e acréscimo de camada com 35 mm de concreto autoadensável na face comprimida. Nove pilares, com alturas de 2000 mm, foram submetidos à flexão composta reta com excentricidade inicial de 60 mm, assim discriminados: um pilar original (Po) com seção transversal de 120 mm x 250 mm; um pilar de referência (Pref) com seção transversal de 155 mm x 250 mm e sete pilares, inicialmente moldados com seção transversal de 120 mm x 250 mm, e após, reforçados através da adição de camada de reforço de 35 mm e diversas configurações de posições de parafusos chumbadores na face comprimida. Exceto o pilar original (Po), os pilares foram submetidos à excentricidade inicial de carga de 42,5 mm, devido ao acréscimo da camada de reforço na face comprimida. Apesar de não ocorrer ruptura dos parafusos chumbadores, não foi possível evitar o desplacamento da camada de reforço. Os resultados obtidos indicam que é possível a reabilitação estrutural de pilares de concreto armado com o uso da metodologia de reforço empregada, obtendo ganho de capacidade de carga média de 3,71 vezes em relação ao pilar original (Po).

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