En Europe, suite à la fermeture de nombreux sites sidérurgiques, une utilisation croissante de laitiers de haut-fourneau d’origine et d’âge variés voit le jour depuis plusieurs années. Cette évolution conduit à une diversification de la composition chimique et minéralogique des laitiers. Connaître l’influence de ces caractéristiques sur la réactivité des laitiers utilisés en substitution du clinker dans les ciments de haut-fourneau (CEM III) devient, dès lors, primordial pour assurer les performances de tels ciments. Dans ce contexte, le présent travail a pour but d’investiguer l’influence de la composition chimique et de l’âge des laitiers sur leur réactivité tant par des essais physico-mécaniques que par une caractérisation physico-chimique et minéralogique de CEM III/B à différentes échéances d’hydratation. L’effet néfaste du vieillissement des laitiers est clairement mis en exergue et son impact diffère selon la composition chimique de départ du laitier. Les ions aluminium engendrent une accélération de l’hydratation et une amélioration des résistances physico-mécaniques à jeune âge mais, à long terme, ils conduisent à une perte de ces dernières. Concernant l’influence des ions titane dans les laitiers, la tendance générale observée est une diminution des performances physico-mécaniques. Sur base de ces résultats, une évaluation de la représentativité de moyens accélérés d’estimation de la réactivité des laitiers est effectuée. Il est mis en évidence que seules les mesures de résistances physico-mécaniques classiques permettent d’évaluer correctement la réactivité des différents laitiers. Une évaluation de la détermination de la teneur en constituants de CEM III/B par la méthode Rietveld est menée par comparaison avec la méthode de dissolution sélective de la norme EN 196-4 et le dosage des constituants par pesée. Moyennant une utilisation adaptée de cette méthode, les résultats obtenus à l’aide de celle-ci sont très encourageants. In Europe, following the closure of many steel plants, an increased use of blast furnace slag (BFS) of various age and origin was born for several years. This evolution leads to a diversification of the chemical and mineralogical composition of the BFS. Knowing the influence of these characteristics on the reactivity of slag used in substitution of clinker in blast-furnace cement (CEM III) becomes, therefore, crucial to ensure the performance of such cements. In this context, this work aims to investigate the influence of chemical composition and age of BFS on their reactivity by both physico-mechanical and physico-chemical and mineralogical characterization of CEM III/B at different times of hydration. The adverse effect of ageing of BFS is clearly highlighted and its impact varies depending on the chemical composition of the BFS. Aluminum ions generate an acceleration of the hydration and improve mechanical strength at early age, but at long term, they lead to a loss of the strength. Regarding the influence of titanium ions in the BFS, the general trend is a decrease of the physical and mechanical performance. Based on these results, an assessment of the representativeness of accelerated means of estimating, the BFS reactivity is done. It is emphasized that only measures of physical and conventional mechanical strength can accurately assess the reactivity of different BFS. An evaluation of the determination of the amount of CEM III/B components by the Rietveld method is based upon comparison with the selective dissolution method from the EN 196-4 norm and components determination by weight. Through appropriate use of this method, the results obtained are very encouraging.

Made available in DSpace on 2014-07-29T15:18:25Z (GMT). No. of bitstreams: 1 dissertacao marcus vinicius mendes.pdf: 2369089 bytes, checksum: 841841ae88caf7c6c9adb67b65e533c5 (MD5) Previous issue date: 2009-10-06 / The durability of reinforced concrete structures is damaged by the degrading action of the penetration of substances in the form of gases, vapors and liquids through the pores and cracks. It is known that water both in its pure form or containing dissolved ions such as chloride, sulphate, carbon dioxide or oxygen ions, can compromise the durability of concrete structures. In reinforced concrete structures at the marine environment, for example, the towers of wind power plants, this degradation can be more intense and accelerated. Thus, in the present study were analyzed concretes with different mineral additions (silica fume, blast furnace slag) and water / binder ratios (0.35, 0.45 and 0.55), with the objective to verify if the inside and cover thickness of concrete have some effect on the mechanisms of transport and also the effect of carbonation (only for concrete with w/b equal to 0.55) in the surface layer of concrete is important enough to make dificult the entry of aggressive agents in concrete. For this, the following tests to evaluate the mass transport in concrete were performed: capillary water absorption (NBR 9779:1995), water penetration under pressure (NBR 10787:1994), air permeability (method Figg), penetrability of chloride ion (ASTM C 1202: 2009), non-steadystate migration test (NT BUILD 492:1999). As a result, it was found that the mineral addition used generally provided an improvement in front of the concrete mechanisms of mass transport. In one of the properties, namely the diffusion coefficient (non-steady-state migration) of concrete with the use of silica fume and blast furnace slag, this has been reduced dramatically, around 11 times for the concrete with w/b equal to 0.55, when it is compared with concrete without mineral addition. It was observed that the inner region of concrete behaved better, in an unexpected way, than concrete cover region for some properties (capillary absorption, water penetration under pressure, penetration of chloride ions). From this conclusion, it can be said that the inner part of concrete is composed of transition zones (aggregated interface / mortar) exposed to facilitate the entry of fluids, gases and ions. About the effect of carbonation, this affected the capillary absorption and air permeability. The results led to explain that the clogging of the pores resulting from the product of carbonation (CaCO3), promoted the refinement of the pores, thus increasing capillary force and, consequently, increasing the capillary absorption. However, for air permeability this effect has damaged the passage of air through the surface layer. Finally, it is important noting that significant correlations were found among tests that evaluated the mechanisms of mass transport, namely, penetration of chloride ions and capillary absorption, diffusion coefficient (non-steady-state migration) and capillary absorption, permeability air and water penetration under pressure, penetration of chloride ions and the diffusion coefficient. / A durabilidade das estruturas de concreto armado é prejudicada pela ação deteriorante da penetração de substâncias na forma de gases, vapores e líquidos através de poros e fissuras. Sabe-se que a água, tanto no seu estado puro ou com íons dissolvidos, como os cloretos, sulfato, dióxido de carbono ou oxigênio, pode comprometer a durabilidade das estruturas de concreto. Em estruturas de concreto armado localizadas em ambiente marítimo como, por exemplo, as torres de energia eólica, essa deterioração pode ser mais intensa e acelerada. Diante disso, no presente trabalho foram analisados concretos com diferentes adições minerais (sílica ativa e escória de alto-forno) e relações água/aglomerante (0,35; 0,45 e 0,55), tendo como objetivo principal verificar se a parte interna e o cobrimento do concreto exercem algum efeito nos mecanismos de transporte e, se o efeito da carbonatação (somente para concretos de relação a/g igual a 0,55) na camada superficial do concreto é relevante a ponto de dificultar a entrada de agentes agressivos no concreto. Para isso, foram realizados os seguintes ensaios para avaliar o transporte de massa no concreto: absorção de água por capilaridade (NBR 9779:1995), penetração de água sob pressão (NBR 10787:1994), permeabilidade ao ar (método de Figg), penetrabilidade de cloretos (ASTM C 1202: 2009), ensaio de migração em regime não estacionário (NT BUILD 492:1999). Como resultado constatou-se que as adições minerais empregadas propiciaram de maneira geral uma melhoria dos concretos frente aos mecanismos de transporte de massa. Em uma das propriedades avaliadas, a saber, o coeficiente de difusão (migração regime não estacionário) dos concretos com o emprego de sílica ativa e escória de alto-forno, esse foi reduzido drasticamente, em torno de 11 vezes para os concretos com relação a/ag igual a 0,55, quando comparado com os concretos sem adição mineral. Quanto à região do concreto, notou-se para algumas propriedades (absorção capilar, penetração de água sob pressão, penetrabilidade de cloretos) que a região interna comportou-se melhor, de maneira inesperada, que a região do cobrimento. Diante dessa conclusão, criou-se uma hipótese para tal comportamento que consistiu em afirmar que a parte interna é composta por zonas de transição (interface agregado/pasta) expostas que facilitam a entrada de fluidos, gases e íons. Já com relação ao efeito da carbonatação, esta afetou a absorção capilar e a permeabilidade ao ar. Os resultados levaram a explicar que a colmatação dos poros, advindos do produto (CaCO3) da carbonatação promoveu o refinamento dos poros, aumentando, assim, a força capilar e, conseqüentemente, o aumento da absorção capilar. No entanto, para permeabilidade ao ar esse efeito dificultou a passagem de ar através da camada superficial. Por último, cabe destacar, que correlações importantes foram obtidas entre os ensaios que avaliaram os mecanismos de transporte de massa, a saber, penetrabilidade de cloretos e absorção capilar, coeficiente de difusão (migração regime não estacionário) e absorção capilar, permeabilidade ao ar e penetração de água sob pressão, penetrabilidade de cloreto e coeficiente de difusão.

En Europe, suite à la fermeture de nombreux sites sidérurgiques, une utilisation croissante de laitiers de haut-fourneau d’origine et d’âge variés voit le jour depuis plusieurs années. Cette évolution conduit à une diversification de la composition chimique et minéralogique des laitiers. Connaître l’influence de ces caractéristiques sur la réactivité des laitiers utilisés en substitution du clinker dans les ciments de haut-fourneau (CEM III) devient, dès lors, primordial pour assurer les performances de tels ciments.<p><p>Dans ce contexte, le présent travail a pour but d’investiguer l’influence de la composition chimique et de l’âge des laitiers sur leur réactivité tant par des essais physico-mécaniques que par une caractérisation physico-chimique et minéralogique de CEM III/B à différentes échéances d’hydratation. L’effet néfaste du vieillissement des laitiers est clairement mis en exergue et son impact diffère selon la composition chimique de départ du laitier. Les ions aluminium engendrent une accélération de l’hydratation et une amélioration des résistances physico-mécaniques à jeune âge mais, à long terme, ils conduisent à une perte de ces dernières. Concernant l’influence des ions titane dans les laitiers, la tendance générale observée est une diminution des performances physico-mécaniques.<p><p>Sur base de ces résultats, une évaluation de la représentativité de moyens accélérés d’estimation de la réactivité des laitiers est effectuée. Il est mis en évidence que seules les mesures de résistances physico-mécaniques classiques permettent d’évaluer correctement la réactivité des différents laitiers.<p><p>Une évaluation de la détermination de la teneur en constituants de CEM III/B par la méthode Rietveld est menée par comparaison avec la méthode de dissolution sélective de la norme EN 196-4 et le dosage des constituants par pesée. Moyennant une utilisation adaptée de cette méthode, les résultats obtenus à l’aide de celle-ci sont très encourageants.<p><p><p>In Europe, following the closure of many steel plants, an increased use of blast furnace slag (BFS) of various age and origin was born for several years. This evolution leads to a diversification of the chemical and mineralogical composition of the BFS. Knowing the influence of these characteristics on the reactivity of slag used in substitution of clinker in blast-furnace cement (CEM III) becomes, therefore, crucial to ensure the performance of such cements. <p><p>In this context, this work aims to investigate the influence of chemical composition and age of BFS on their reactivity by both physico-mechanical and physico-chemical and mineralogical characterization of CEM III/B at different times of hydration. The adverse effect of ageing of BFS is clearly highlighted and its impact varies depending on the chemical composition of the BFS. Aluminum ions generate an acceleration of the hydration and improve mechanical strength at early age, but at long term, they lead to a loss of the strength. Regarding the influence of titanium ions in the BFS, the general trend is a decrease of the physical and mechanical performance.<p><p>Based on these results, an assessment of the representativeness of accelerated means of estimating, the BFS reactivity is done. It is emphasized that only measures of physical and conventional mechanical strength can accurately assess the reactivity of different BFS. <p><p>An evaluation of the determination of the amount of CEM III/B components by the Rietveld method is based upon comparison with the selective dissolution method from the EN 196-4 norm and components determination by weight. Through appropriate use of this method, the results obtained are very encouraging.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

The topic of this work is the monitoring of the effect of zinc on the hydration process in Portland mixed cement (specifically with the addition of finely ground granulated blast-furnace slag, high temperature fly ash and fluidized bed combustion filter ash). How much zinc and at what time it remains in the pore solution during hydration. Activation energy of a mixture of cement with zinc in the form of soluble salts (Zn(NO3)2.6H2O and ZnCl2) and insoluble oxide (ZnO) by isothermal calorimetry was also investigated. The XRF method has shown composition during hydration. The zinc retardation effect was investigated by isothermal calorimetry and activation energy was calculated using this method. The XRF and ICP-OES methods were used to measure the zinc content of the pore solution. And the amount of portlandite was monitored by the DTA and XRF method.

This work is devoted to study the influence of the composition on mechanical properties of high performance concret based on portland cement. 29 samples of high performance concrete (HPC) warying in composition were prepared. The constituents used for HPC preparation were: cement Aalborg White, silica fume, finelly ground blast furnace slag, finelly ground silica, calcinated bauxite and polycarboxylate based superplasticizer. The mechanical parameters (flexural and compressive strength) of the samples were observed after 7 and 28 days of moist curing. Compressive strength values after 28 days were in the range of 92 to 194 MPa and the flexural strength values were in the range of 7 to 23 MPa (without using of fiber reinforcement). The graphs showing mechanical parameters depending on the mixture composition were constructed and consequently evaluated.

Civil engineering development is connected with the application of new construction methods and the development of new building materials. Concrete, as one of the basic building materials, is part of this development. A major turning point in the development of concrete and its properties occurred with the use of new, more efficient plasticizing additives. This allowed to produce concrete with lower water cement ratio, while increasing the strength of concrete. Gradually, the compressive strength of concrete boundary has moved by several levels, when there are currently commonly used concrete with strength of about 100 N/mm2 and with the special methods of concrete production strength range from 250 to 300 N/mm2. A negative aspect of the development of (ultra) high-strength concrete is their energy and economic demands. A characteristic feature of high-strength concrete is a high content of cement and very fine admixtures, especially silica fume. One way to improve the economics of these types of concrete is the application of cheaper admixture based on industrial waste. The content of this work is the observation and description of the properties of high-strength concrete and reactive powder concrete, in which the admixtures were based on industrial waste were applied. Part of this work is the comparison of economic parameters for individual types of concrete.

The theme of this work is to monitor the effect of zinc on the properties of blended Portland cements. Zinc was tested in the form of two-soluble salts: Zn(NO3)22 H2O and ZnCl2 and a very slightly soluble compound ZnO. Blended cements were prepared by partial replacement with finely ground granulated blast furnace slag, high-temperature and fluidized bed combustion filter fly ash. Flow properties were studied on the prepared pastes. Impact on hydration reactions was examined by using of isothermal and isoperibolic calorimetry. Flexural and compressive strength were measured as mechanical properties of the prepared test specimens. The phase composition of the prepared composites and incorporation of zinc ions in the cement matrix via leaching tests and FTIR analyzes were also studied. Microstructure development of cement samples was tested by SEM analysis with EDS. Influence on ecotoxicity was also measured.

A method of producing steel that is not used in Sweden today is direct reduction using natural gas, a method which could has enormous potential in the future of steelmaking. Historically, steelmaking prioritized productivity and profitability. However, other aspects such as safety, sustainability, and environmentally friendliness have become increasingly important to Swedish steelmakers. This study evaluates the usage of natural gas to  directly reduce iron ore into the porous form known as iron sponge, then finally processing that sponge into crude steel. The technology available today is assessed through a literature review, then two calculative data-based model: using DRI sponge in a traditional integrated steelmaking line or replacing steel scrap with it in an electric arc furnace. While this technology is used in many regions where natural gas is plentiful, it has not yet been used in Sweden. Now, when the Swedish natural gas network is expanding and the vehicular transportation of liquid natural gas is becoming more and more viable, it is a prime situation to evaluate direct reduction in Sweden. While models require assumptions and estimations, they suggest that DRI will absolutely be a viable option in the years to come. Integrated plant operators can reduce their immense carbon emissions for a reasonable price, while DRI sponge melting in an electrical arc furnace can either help steelmakers escape the volatile scrap market or be used to replace the blast furnace as a whole in the future. / En metod för att producera stål som inte används i Sverige idag är direkt reduktion med hjälp av naturgas, en metod som har en enorm potential i framtida ståltillverkning. Historiskt har ståltillverkningen prioriterat produktivitet och vinst, men säkerhet, hållbarhet, och miljövänlighet har blivit områden mer och mer viktiga för svenska ståltillverkare. Den här studien utvärderar användningen av naturgas för att direkt reducera järnmalm till den porösa formen känd som järnsvamp, och sen bearbeta den till primärt stål. Teknologin som flnns idag utvärderas genom en litteraturstudie, vars data beräknas till två scenariomodeller: användningen av järnsvamp i ett traditionellt integrerat stålverk eller genom att ersätta stålskrot med järnsvamp i ljusbågsungen. Den här teknologin används redan idag i regioner där naturgas är lättillgängligt, men har hittills inte använts i Sverige. Men nu när Sveriges naturgasnät byggs ut och fordonstransporterad flytande naturgas blir mer och mer kostnadseffektiv så är det lämpligt att utvärdera direkt reduktion i Sverige. Modellerna kräver antaganden och uppskattningar, men de pekar på att direkt reducering av järnmalm kommer att vara en genomförbar metod för ståltillverkning i en nära framtid. Integrerade masugnslinjer kan minska sina enorma koldioxidutsläpp till ett rimligt pris, och järnsvampssmältning i ljusbågsugn kan hjälpa ståltillverkare att undanfly den instabila stålskrotsmarknaden eller användas för att helt ersätta masugnsproduktion i framtiden.

Tesis por compendio / [ES] Esta tesis englobada dentro del programa de doctorado en ingeniería de la construcción sigue la línea de investigación en sostenibilidad y gestión de la construcción. Las investigaciones se han centrado en el desarrollo de cementos de activación alcalina (CAA) obtenidos a partir de residuos con el fin de reducir tanto el coste económico como medioambiental. Este hecho implicaría la reducción en el uso tanto de materias primas, en el caso de los precursores, como de reactivos químicos en el caso de los activadores. La tesis doctoral que se presenta estudia el uso de diferentes mezclas de residuos como precursores: cerámica sanitaria, catalizador gastado de craqueo catalítico, escoria de alto horno y ceniza volante de central térmica en la preparación de morteros. Así mismo, utiliza también CAA, obtenidos a partir de residuos en la estabilización de suelos. En este último caso también se han usado residuos en la preparación de activadores como son las cenizas obtenidas en la combustión de biomasa. Los resultados obtenidos ponen de manifiesto la viabilidad en el uso de residuos para la preparación de CAA, y la posibilidad incluso de ser usados en contextos de subdesarrollo. / [CA] Aquesta tesi englobada dins del programa de doctorat en enginyeria de la construcció segueix la línia d'investigació en sostenibilitat i gestió de la construcció. Les investigacions s'han centrat en el desenvolupament de ciments d'activació alcalina (CAA) obtinguts a partir de residus amb la finalitat de reduir tant el cost econòmic com mediambiental. Aquest fet implicaria la reducció en l'ús tant de matèries primeres, en el cas dels precursors, com de reactius químics en el cas dels activadors. La tesi doctoral que es presenta estudia l'ús de diferents mescles de residus com a precursors: ceràmica sanitària, catalitzador gastat de craqueig catalític, escòria d'alt forn i cendra volant de central tèrmica en la preparació de morters. Així mateix, utilitza també CAA, obtinguts a partir de residus en l'estabilització de sòls. En aquest últim cas també s'han usat residus en la preparació d'activadors com són les cendres obtingudes en la combustió de biomassa. Els resultats obtinguts posen de manifest la viabilitat en l'ús de residus per a la preparació de CAA, i la possibilitat de ser usats fins i tot en contextos de subdesenvolupament. / [EN] This doctoral thesis encompassed within the doctoral program in construction engineering follows the research line in sustainability and construction management. The research has focused on the development of alkaline activated cements (AAC) obtained from waste to reduce the economic and environmental cost. This fact would imply a reduction in the use of raw materials in the case of precursors, and chemical reagents in the case of activators. The doctoral thesis that is presented studies the use of different waste mixtures as precursors: sanitary ceramics, spent fluid cracking catalyst, blast furnace slag and fly ash from thermal power plants in the preparation of mortars. Likewise, also is used CAA obtained from residues in soil stabilization. In the latter case, residues have also been used in the activators preparation, such as the ashes obtained in the combustion of biomass. The results obtained show the viability in the use of residues for CAA preparation, and the possibility of being used even in underdeveloped contexts. / Agradecer al Ministerio de Ciencia e Innovación por el soporte a mi investigación, mediante los fondos del proyecto APLIGEO BIA2015-70107-R y los fondos FEDER. También a las empresas: Ideal Standard por suministrar residuos de cerámica sanitaria, Omya Clariana S.A. por suministrar catalizador gastado del craqueo catalítico, a Balalva S.L. por suministrar cenizas volantes, a Cementval por suministrar escorias de alto horno, a Heineken España S.A. por el suministro de residuo del filtrado de cerveza (tierras diatomeas), a DACSA GROUP por la ceniza de cáscara de arroz, y a PAVASAL por suministrar suelo de tipo dolomítico. Támbien al servicio de Microscopía electrónica y al Instituto de Ciencia y Técnología del Hormigón de la Universitat Politècnica de València. / Cosa Martínez, J. (2022). Utilización de mezclas de residuos para la obtención de cementos de activación alcalina: aplicación en morteros y suelos estabilizados [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/185221 / TESIS / Compendio

Steel production is today one of the most CO2-demanding activities and causes 8% of the global emissions of GHG. It is crucial for the industry to reduce its emissions radically in order to be in line with the goals of the Paris Agreement and the Science-Based Target initiative. Ovako AB, one of the leading producers of high-strength engineering steel, has been at the forefront when it comes to sustainability initiatives within the industry. Heavy investments are being made into sustainable steel production methods and technologies and to make this viable, the company has, from January 1st, 2022, started to put a price premium on their steel products of 30 € per tonne. This study aims to answer the question of how Ovako's customers, based on the three different industries of mining, automotive, and bearing, experience this price premium and how a green steel can justify this surcharge. Furthermore, this case study aims to understand the extent to which those customers require carbon neutrality when sourcing steel. Connected to the findings from the innovation theories and the literature, this study aims to answer the question of how sustainable innovations may influence future competitiveness regarding engineering steel. To answer these questions, interviews with key individuals from different customers of Ovako were conducted. Moreover, focus groups at Ovako with relevant employees have been held at the same time as a literature study has been conducted. Based on the answers obtained from the data collection, a thematic analysis has been performed where overarching themes have been identified. Additionally, a carbon impact calculator has been used to calculate the carbon reduction potential of using a carbon-neutral engineering steel in three different applications connected to the three industries investigated, namely a complete bearing, a drill bit, and a final drive unit. The results from the calculations as well as the answers obtained regarding the research questions will be presented in the conclusion chapter of the report.