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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.
1

Acceptable Vibrations on Green Concrete

Watkins, Mitchell Lewis 14 December 2013 (has links)
This thesis contains the results of various green concrete samples subjected to different vibration intensities to determine how green concrete withstands against these vibration intensities. The green concrete was exposed to these vibrations at times before, during, and after the concrete had set. The concrete was also exposed to different timed durations while being subjected to the different vibration levels. Every batch of concrete mixed included a controlled (un-vibrated) set of cylinders and a vibrated set of cylinders. The compressive strength and the resistivity of these concrete cylinders were measured and compared to determine if there was any significant difference between the two sets. It was found that the vibrations subjected to the cylinders did not create a significant effect; given the vibrations levels and timed durations stay within the limits of this study.
2

Hur mogen är marknaden för klimatsmart betong och dess aktörer?

Awn, Rim Fares, Corona, Jaqueline January 2020 (has links)
Carbon dioxide emissions have long proven to be one of the greenhouse gases that affect our planet's climate and environment. With the upcoming EU targets and Sweden's own net zero targets, the construction and real estate sector is required to work with climate-smart materials to construct the buildings of the future. The net zero target for year 2045 requires a joint pool of power from all companies to find innovative solutions to reduce carbon dioxide emissions. The purpose of this study was to investigate how conscious and active the construction and real estate sector is for climate-smart concrete through a survey and comparison of different typ of concretes EPDs. The work aims to investigate how far the development has taken place and to investigate how the market has adopted the new products that are available. The purpose was also to investigate which alternative additives are most common and the advantages and disadvantages of the climate-smart concrete. Climate smart is a term for concrete that contains a lower percentage of Portland cement clinker than the traditional concrete. A questionnaire was created to answer the purpose of the study. The survey sent out involved questions about how companies view the new environmental target for year 2045. As well as investigating how the construction and real estate sector works together to achieve the goal of reducing carbon dioxide emissions by 85% less than in year 1990. A comparison was made between three different EPDs of climate-smart concrete and two reference concrete with ordinary Portland cement clinker. Reference concrete one is a standard value derived from previous studies made and reference concrete two is an EPD value. This was done to investigate the amount of carbon dioxide they emit at the production stage. A reference building was used to calculate the amount of concrete. The result shows that the comparison between reference concrete one with the standard value and the three climate-smart concrete from Svensk Betong, Betongindustrin and Swerock gives a carbon dioxide reduction of 29.3%. And the comparison with reference concrete two with the associated EPD value received a percent climate reduction of only 2.8%. The future will require the construction and real estate industry to invest time and training to work with climate-smart concrete. More in-depth work could be explored and mapped as to which are the major obstacles in construction projects. How companies can work to get the entire value chain to work together for a climate-smart thinking and primarily to get the developer to invest in improved concrete with less climate impact.
3

A Statistical Modeling Approach to Studying the Effects of Alternative and Waste Materials on Green Concrete Properties

Jin, Ruoyu 30 August 2013 (has links)
No description available.
4

Förekomsten av tungmetaller i Grön betong : En studie om tungmetaller i grön betong jämfört med Naturvårdsverketsriktlinjer. / A study on heavy metals in green concrete compared to the Swedish Environmental Protection Agency's guidelines.

Heidari, Ali masih, Hashemi, Ehsan January 2023 (has links)
Examensarbetet som omfattar 22,5 högskolepoäng har utförs som den slutliga delen avhögskoleingenjörsprogrammet i byggteknik, inriktning husbyggnad vid KarlstadsUniversitet.  Hållbarhet är ett viktigt ämne som berör företag av alla slag. Ingen bransch kan undvika attfundera över hur de kan främja hållbarhet. Frågan om hur varje bransch kan göra detta äralltid viktig. Genom regeringens förslag och överenskommelser står det klart attkoldioxidutsläppen ska halveras till 2030. Det är dock inte klart hur koldioxidutsläppen skahalveras.  Grön betong är en typ av miljövänlig betong där en del av cementen ersätts av masugnsslaggeller flygaska som har tagits fram av Cementa och Swecem. De två vanligaste typerna avcement som används i grön betong är Merit och Anläggningscement FA. Merit kommer frånSwecem medan Anläggningscement AF kommer från Cementa. Målet med denna typ avbetong är att minska byggbranschens koldioxidutsläpp. Rapporten syftar till att ge läsarna en överblick över de olika typer av cement som användsvid tillverkning av grön betong och dess miljökonsekvenser. Rapporten bygger på en mängdlitteraturforskning och dialog med experter från Swecem och Cementa för att få en bättreförståelse för fenomenet grön betong. Den tar också hänsyn till hur deras produkt bidrar tillhållbarhet. En labundersökning gjordes för att jämföra halterna av tungmetaller i olika typerav cement, speciellt grön betong kontra konventionell betong. S1 titan detektorn används föratt mäta och samla in data, detektorn använder röntgenfluorescens (XRF) som mätmetod. Studien fann att både produkterna Merit och Anläggningscement AF innehöll lägretungmetaller än Naturvårdsverkets gränsvärde. Grön restbetong kan återvinnas på sammasätt som en vanlig betong till ballast eller vägfyllnadsmaterial. Grön restbetong innehållerendast tungmetaller som finns i själva cementen. Grön rivningsbetong som innehåller avfallsåsom brandskydd, värmeisolering, skumplast, elinstallationer, fogmassor och rör kanpotentiellt innehålla högre halter av tungmetaller och kan leda till potentiell lakning avfarliga ämnen till naturen. / The degree project, which includes 22.5 higher education credits, has been carried out as the final part of the higher education engineering program in construction technology, majoring in building construction at Karlstad University. Sustainability is an important topic that affects companies of all kinds. No industry can avoid thinking about how they can promote sustainability. The question of how each industry can do this is always important. Through the government's proposals and agreements, it is clear that carbon dioxide emissions are to be halved by 2030. However, it is not clear how carbon dioxide emissions are to be halved. Green concrete is a type of environmentally friendly concrete where part of the cement is replaced by blast furnace slag or fly ash that has been produced by Cementa and Swecem. The two most common types of cement used in green concrete are Merit and Anläggningscement FA. Merit comes from Swecem, while Construction cement AF comes from Cementa. The goal of this type of concrete is to reduce the construction industry's carbon dioxide emissions. The report aims to give readers an overview of the different types of cement used in the production of green concrete and its environmental consequences. The report is based on a lot of literature research and dialogue with experts from Swecem and Cement to gain a better understanding of the phenomenon of green concrete. It also takes into account how its product contributes to sustainability. A lab study compared the levels of heavy metals in different types of cement, especially green concrete versus conventional concrete. The S1 titanium detector is used to measure and collect data, the detector uses X-ray fluorescence(XRF) as the measurement method. The study found that both the products Merit and Anläggningscement AF contained lower heavy metals than the Environmental Protection Agency's limit value. Residual green concrete can be recycled in the same way as ordinary concrete for aggregate or road-filling material. Residual green concrete only contains heavy metals found in the cement itself. Green demolition concrete that contains waste such as fire protection, thermal insulation, foam plastic, electrical installations, grouts, and pipes can potentially contain higher levels of heavy metals and can lead to the potential leaching of hazardous substances into nature.
5

Anwendungsorientierte Mischungsentwicklung und Ökobilanz eines zementreduzierten Ökobetons

Hilgenfeld, Jonathan 02 February 2021 (has links)
Die vorliegende Thesis befasst sich mit der Mischungsentwicklung eines zementreduzierten Ökobetons für die Verwendung in einem ökologisch verbesserten Deckensystem. Dafür wurden mithilfe eines in Microsoft Excel aufgestellten physikalischen Analysemodells – dem Compaction-Interaction Packing Model nach FENNIS – Rezepturen entwickelt, die durch eine optimierte Packungsdichte einen geringeren Zementleimbedarf aufweisen. Dabei gelang es, Zement teilweise durch feine Kalksteinmehle zu ersetzen und eine CO2-sparende Mischung mit einem reduzierten Zementgehalt von 150 kg je Kubikmeter Beton herzustellen, welche die an sie gestellten Anforderungen erfüllt – u. a. bezogen auf Festigkeit (Festigkeitsklasse C 20/25), Verarbeitbarkeit (Konsistenzklasse C3) und Alkalität (pH-Wert > 10). Diese Eigenschaften wurden experimentell geprüft. Zwar wurden bei der auf empirischen Daten beruhenden Prognose von Festigkeit und Konsistenz im Modell nur teilweise realitätsnahe Werte ermittelt, das Modell stellte sich insgesamt jedoch als zielführendes Instrument bei der Mischungsentwicklung von Ökobetonen heraus.:1 Einleitung 2 Verringerung der Umwelteinwirkungen bei der Betonherstellung 3 Methodik der Mischungsentwicklung zementreduzierter Ökobetone 4 Packungsdichteberechnung mit dem Compaction-Interaction Packing Model nach FENNIS 5 Mischungsentwicklung eines Ökobetons im Rahmen des Forschungsvorhabens GRO-COCE 6 Herstellung der Auswahlmischungen und experimentelle Ermittlung von Betoneigenschaften 7 Eingrenzung einer Zielmischung 8 Diskussion der Ergebnisse 9 Zusammenfassung und Ausblick / The present thesis deals with the mix development of a cement-reduced eco-concrete for the use in an ecologically improved ceiling system. For this purpose, a physical analysis model built in Microsoft Excel – the Compaction-Interaction Packing Model according to FENNIS – was used to develop recipes which, due to an optimised packing density, have a low cement paste requirement. It was possible to partially replace cement with fine limestone powders and to produce a CO2-saving mixture with a reduced cement content of 150 kg per cubic metre of concrete, which meets the requirements placed on it – among other things with regard to strength (strength class C 20/25), workability (consistency class C3) and alkalinity (pH-value > 10). These properties were tested experimentally. Although only partially realistic values were determined in the model for the prediction of strength and consistency based on empirical data, the model turned out to be a suitable instrument for mix developments of eco-concretes.:1 Einleitung 2 Verringerung der Umwelteinwirkungen bei der Betonherstellung 3 Methodik der Mischungsentwicklung zementreduzierter Ökobetone 4 Packungsdichteberechnung mit dem Compaction-Interaction Packing Model nach FENNIS 5 Mischungsentwicklung eines Ökobetons im Rahmen des Forschungsvorhabens GRO-COCE 6 Herstellung der Auswahlmischungen und experimentelle Ermittlung von Betoneigenschaften 7 Eingrenzung einer Zielmischung 8 Diskussion der Ergebnisse 9 Zusammenfassung und Ausblick
6

Συστηματική μελέτη αυτοσυμπυκνούμενου κισσηροδέματος / Pumice aggregate self compacting concrete (PASCC)

Καφφετζάκης, Μιχαήλ 09 October 2014 (has links)
Το θέμα της παρούσης Διδακτορικής Διατριβής είναι η συστηματική μελέτη του Αυτοσυμπυκνούμενου Κισσηροδέματος (ΑΣΚ). Ο βασικός σκοπός της υπήρξε η παραγωγή μειγμάτων δομικού ΑΣΚ, προτείνοντας παράλληλα μία μεθοδολογία σύνθεσης, εφαρμόσιμη για κάθε είδος Αυτοσυμπυκνούμενου Σκυροδέματος (ΑΣΣ). Ακόμη, έγινε προσπάθεια να διερευνηθούν τομείς στους οποίους η γνώση για το Αυτοσυμπυκνούμενο Ελαφροσκυρόδεμα (ΑΣΕΣ) είναι ακόμη ελλιπής, όπως η συνάφεια χάλυβα-ΑΣΕΣ, η συμπεριφορά γραμμικών στοιχείων οπλισμένου ΑΣΕΣ έναντι κάμψης και διάτμησης, η κατανομή και οι μέγιστες τιμές των πιέσεων που ασκεί το νωπό ΑΣΕΣ σε ξυλοτύπους και τα χαρακτηριστικά ανθεκτικότητάς του. / In this study an extended investigation of PASCC properties is conducted. The main scope was to produce structural PASCC mixtures, by proposing a mix design methodology applicable for every type of Lightweight Aggregate Self-Compacting Concrete (SCC). Moreover, there has been an attempt to investigate fields where the available knowledge for LWASCC is limited, such as the steel-PASCC bond characteristics, the response of reinforced PASCC elements under reversed bending and shear actions, the formwork pressure development during and after PASCC casting and selected PASCC durability characteristics.
7

Kartläggning av vad som krävs för att svenska byggföretag ska övergå till miljöbetong : En enkätundersökning

Lindqvist, Moa, Lindqvist Berglund, Lisa January 2020 (has links)
Today Portland cement based concrete is used in great extent in building construction, which is an environmental problem as cement production stands for 5-8 % of total global greenhouse gases.  A need for a more environmentally friendly concrete is growing. In a literature study it’s established that there is extensive research in the field of more environmentally friendly concrete, where the results proves that the environmentally friendly concrete shows as good, or better, properties than the concrete with Portland cement. Concrete is one of the most important construction materials and there are high demands on its correct performance. Construction companies in Sweden have a rumor of being indisposed to change and inert to embrace new material and means of construction. This survey intended to map what properties the environmentally friendly concrete should meet to encourage Swedish construction companies to use it. The survey was designed with a statement and criteria derived from the literature study. The literature study consists of peer reviewed articles found via the databases Libris and Scopus through the search words  “concrete”, “green concrete”, “fly ash”, “sustainable” och “challenges”. The respondents were asked to rate the criteria from one to four on how well the statement agrees with the respondents values. The collected data is presented with a bar graph. The result shows that the highest rated criterion is its Long term properties and the lowest rated criterion is a Possible introduction of a company specific emission ceiling.
8

Expansion of Sickla treatment plant : A study about the replacement of standard concrete to green concrete / Utbyggnad av Sickla reningsverk : En studie om ersättning av standardbetong mot grön betong

Rasool, Sava Tnar, Sharif, Omar January 2020 (has links)
Stockholm Vatten has decided to close down the Bromma waste water treatment plantand manage the waste water from Bromma together with the waste water from the formerEolshällsverket to Henriksdal’s waste water treatment plant. Henriksdals wastewater treatment plant will be expanded for higher purification requirements and loads,estimated to be finished until 2040. This entails extensive renovations and additionsto the existing treatment plant in and on Henriksdalsberget, as well as a major expansionof the Sickla plant.The purpose of the study is to investigate an environmentally friendly alternative tothe standard concrete that will be used for the expansion of the Sickla plant. The largestenvironmental villain in concrete is the cement. The aim of this study has beento replace the cement with environmentally friendly additives in the largest possibleamount, thus reducing the negative impact of the cement on the environment.In the present study, a review was made of obtained data with exposure classes, then aliterature study was performed to gain knowledge in the area. With help from experts,two fictitious recipes for each exposure class have been calculated for the standardconcrete and the green concrete. In this way, a careful comparison between the concretetypes was made of the cement’s impact on global warming. Thereafter, a study wascarried out on existing EPDs, which were incorporated into the One Click LCA (2015)software. An LCA in the mentioned software was carried out, which enabled data to becompiled and a comparison of the climate impact between the four different fictitiousrecipes has been done.Compiled and compared data from LCA and analysis of EPDs show that 70% of thestructure with exposure class XD2 gets a 47% reduction in global warming when usinggreen concrete instead of standard concrete. Furthermore, the results show that theremaining 30% of the structure with exposure class XF3/XC4 gets a 20% reductionwhen using green concrete instead of standard concrete. The total reduction in globalwarming when using green concrete instead of standard concrete for the expansion ofSickla treatment plant was calculated to be 40%. / Stockholm Vatten har beslutat att lägga ned Bromma reningsverk och leda avloppsvattnetfrån Bromma tillsammans med avloppsvattnet från det forna Eolshällsverkettill Henriksdals reningsverk. Henriksdals reningsverk ska byggas ut för högre reningskravoch belastningar beräknade till år 2040. Detta medför omfattande om- och tillbyggnationeri det befintliga reningsverket i och på Henriksdalsberget samt en storutbyggnad av Sicklaanläggningen.Syftet med detta arbete är att undersöka ett miljövänligare alternativ till standardbetongensom ska användas vid utbyggnaden av Sicklaanläggningen. Då den främsta”miljöboven” i betongen är cementet har målet med denna studie varit att ersätta cementetmed miljövänliga tillsatsmaterial i största möjliga mängd, i syfte att minskacementets negativa inverkan på miljön.I föreliggande arbete har en genomgång utförts på erhållna data med exponeringsklasser,därefter påbörjades en litteraturstudie i syfte att inhämta kunskaper inomområdet. Med hjälp av experter har två fiktiva recept för respektive exponeringsklassräknats fram för standardbetongen och den gröna betongen. Med denna metod genomfördesen noggrann jämförelse mellan de olika recepten avseende cementets inverkanpå den globala uppvärmningen. Därefter undersöktes existerande EPD:er, vilka infogadesin i programvaran One Click LCA (2015). En LCA i den nämnda programvaranutfördes, vilket möjliggjorde att data kunde sammanställas och en jämförelse av klimatpåverkanmellan de fyra olika fiktiva recepten kunde genomföras.Sammanställd och jämförd data från LCA och analys av EPD:er visar att 70% av konstruktionenmed exponeringsklass XD2 får en reducering på 47% på den globala uppvärmningenvid användning av grön betong istället för standardbetong. Vidare visarresultatet att resterande 30% av konstruktionen med exponeringsklass XF3/XC4 fåren reduktion på 20% vid användning av grön betong istället för standardbetong. Dentotala reduktionen på den globala uppvärmningen vid användning av grön betongistället för standardbetong för utbyggnaden av Sickla reningsverk beräknades till 40%.
9

Utilização de descarte de resíduos têxtil (poliamida/poliester), como agregado, em concreto / Use of textile waste disposal (Poliamide/Poliester), such as aggregate in concrete

Petterson Borges Machado 23 March 2015 (has links)
Neste trabalho são apresentadas algumas características físicas, vantagens e viabilidade do uso do pó de tecido, proveniente do processamento de resíduos têxteis que são descartados em confecções em geral. A produção e utilização desse tipo de pó diminui o impacto ambiental e se mostra viável economicamente, pois é produzido facilmente a partir do processamento de resíduos, que seriam descartados na natureza. O presente trabalho mostra o estudo da produção do pó de tecido e a sua substituição parcial do agregado miúdo natural na produção de concretos de cimento Portland convencionais. Para comprovar a viabilidade técnica e econômica do uso do pó de tecido foram analisadas características do agregado como sua composição granulométrica, e seu comportamento nos ensaios de abatimento tronco de cone (Slump Test). Uma relação água-cimento também foi convencionada a um concreto usual com resistência esperada de 27MPa. Com estes dados foi definido um traço para o concreto utilizando 5% e 15% de agregado pó de tecido, substituindo a areia. A pesquisa apresenta os resultados de resistência à compressão simples dos corpos de prova cilíndricos de concreto aos 28 dias. Verificou-se que as amostras não apresentaram diferenças significativas de resistência entre si, tão pouco com relação às resistências de um concreto convencional produzido somente com agregado miúdo natural. Entretanto, houve uma melhora nos resultados dos ensaios à compressão, principalmente no concreto com 15% de pó de tecido. / On this work are present some physical characteristics, advantages and viability of the use of the fabric dust, proceeding from the processing of textile residues that are discarded in confections in general. The production and use of this type of dust diminish the ambient impact and if it shows economically viable, therefore it is produced easily from the processing of residues, which would be discarded in the nature. The present work shows to the study of the production of the dust of tissue its partial substitution of the natural small aggregate in the production of concrete of Portland cement conventional. To prove the viability economic technique and of the use of the fabric dust they had been analyzed characteristic of the aggregate as its grain sized composition, and its behavior in the discouragement assays cone trunk (Slump Test). A relation water-cement also was stipulated to the one usual concrete with resistance waited of 27 MPa. With these data a trace for concrete using 5% and 15% of added fabric dust, substituting was defined the sand. The research presents the results of simple compressive strength of the cylindrical bodies of test of concrete to the 28 days. It was verified so little that the samples had not presented significant differences of resistance between itself, with regard to the resistance of a conventional concrete only produced with natural small aggregate. However, the compression had an improvement in the results of the assays, mainly in the concrete with 15% of fabric dust.
10

Utilização de descarte de resíduos têxtil (poliamida/poliester), como agregado, em concreto / Use of textile waste disposal (Poliamide/Poliester), such as aggregate in concrete

Petterson Borges Machado 23 March 2015 (has links)
Neste trabalho são apresentadas algumas características físicas, vantagens e viabilidade do uso do pó de tecido, proveniente do processamento de resíduos têxteis que são descartados em confecções em geral. A produção e utilização desse tipo de pó diminui o impacto ambiental e se mostra viável economicamente, pois é produzido facilmente a partir do processamento de resíduos, que seriam descartados na natureza. O presente trabalho mostra o estudo da produção do pó de tecido e a sua substituição parcial do agregado miúdo natural na produção de concretos de cimento Portland convencionais. Para comprovar a viabilidade técnica e econômica do uso do pó de tecido foram analisadas características do agregado como sua composição granulométrica, e seu comportamento nos ensaios de abatimento tronco de cone (Slump Test). Uma relação água-cimento também foi convencionada a um concreto usual com resistência esperada de 27MPa. Com estes dados foi definido um traço para o concreto utilizando 5% e 15% de agregado pó de tecido, substituindo a areia. A pesquisa apresenta os resultados de resistência à compressão simples dos corpos de prova cilíndricos de concreto aos 28 dias. Verificou-se que as amostras não apresentaram diferenças significativas de resistência entre si, tão pouco com relação às resistências de um concreto convencional produzido somente com agregado miúdo natural. Entretanto, houve uma melhora nos resultados dos ensaios à compressão, principalmente no concreto com 15% de pó de tecido. / On this work are present some physical characteristics, advantages and viability of the use of the fabric dust, proceeding from the processing of textile residues that are discarded in confections in general. The production and use of this type of dust diminish the ambient impact and if it shows economically viable, therefore it is produced easily from the processing of residues, which would be discarded in the nature. The present work shows to the study of the production of the dust of tissue its partial substitution of the natural small aggregate in the production of concrete of Portland cement conventional. To prove the viability economic technique and of the use of the fabric dust they had been analyzed characteristic of the aggregate as its grain sized composition, and its behavior in the discouragement assays cone trunk (Slump Test). A relation water-cement also was stipulated to the one usual concrete with resistance waited of 27 MPa. With these data a trace for concrete using 5% and 15% of added fabric dust, substituting was defined the sand. The research presents the results of simple compressive strength of the cylindrical bodies of test of concrete to the 28 days. It was verified so little that the samples had not presented significant differences of resistance between itself, with regard to the resistance of a conventional concrete only produced with natural small aggregate. However, the compression had an improvement in the results of the assays, mainly in the concrete with 15% of fabric dust.

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