A durabilidade dos edifícios em concreto armado só pode ser alcançada se for atendido um conjunto de requisitos e critérios nas etapas de projeto, execução e manutenção, nas quais os materiais envolvidos precisam ser adequadamente especificados, produzidos e empregados, de acordo com as respectivas rotinas dessas etapas. Assim, o requisito genérico de proteção das armaduras de aço carbono, para a durabilidade de estruturas, é contemplado por vários critérios, desde a etapa de projeto. Esta dissertação trata dos critérios pertinentes à qualidade do concreto e visou contribuir para a evolução de procedimentos para o controle tecnológico de concretos estruturais de cimento Portland, em atmosferas marítimas e urbanas, em clima tropical, com vistas à proteção de armaduras de aço carbono. O programa experimental estudou três lotes diferentes de concretos estruturais, semelhantes quanto a especificações básicas de abatimento: 10 ± 2 cm, de fck 30 MPa e para ambiente classe III da NBR 6118 (2003). O objetivo foi caracterizar e analisar a influência de propriedades físicas do estado fresco sobre o estado endurecido de concretos, dentro da faixa de consistência citada, com ênfase nas propriedades relacionadas ao teor de ar das misturas e suas respectivas resistências à carbonatação e ao ingresso de íons cloreto. A amostragem, os ensaios no estado fresco e a moldagem dos corpos-de-prova foram realizados durante três concretagens conduzidas em duas obras de edifícios de múltiplos andares, na cidade de João Pessoa/PB. As composições e a produção dos lotes ficaram a cargo da central dosadora e fornecedora do concreto em cada obra. O lote inicial serviu para o treinamento da equipe, em campo e laboratório, com amostragem de seis caminhões. Os outros dois lotes, identificados como 1 e 2, foram caracterizados em condições bastante semelhantes, sempre pela mesma equipe, e representados pela amostragem de cinco e seis caminhões, respectivamente. As propriedades medidas no estado fresco foram: abatimento do tronco de cone pela ABNT NBR NM 67 (1998); teor de ar por método pressométrico da ABNT NBR 47 (2002); massa específica pela ABNT NBR 9833 (2008); relação água/materiais secos por analogia à ABNT NBR 9605 (1992); e compactabilidade dos concretos adensado e não adensado, por adaptação da BS EN 12350-4 (2008). Para o estudo das propriedades no estado endurecido, os corpos-de-prova eram cilíndricos, com 10 cm de diâmetro e 20 cm de altura, e foram maturados por dois métodos adaptados do Tipo A da ASTM C 684 (1999). Certas propriedades foram ainda caracterizadas para condições normais de cura da ABNT NBR 5738 (2003). As propriedades estudadas no estado endurecido foram: resistência à compressão pela ABNT NBR 5739 (2007); resistência à tração por compressão diametral pela ABNT NBR 7222 (1994); absorção de água por capilaridade pela ABNT NBR 9779 (1995); absorção de água total e índice de vazios pela ABNT NBR 9778 (2005); resistência à carbonatação em câmara com CO2 (5%; UR 65 + 10 %; 23 + 3 °C); e resistência à penetração de cloretos e CO2, por três ciclos de um dia de molhagem e 27 dias de secagem, entre sete e 91 dias. De modo complementar, foram moldados corpos-de-prova específicos de aço e concreto, para medidas de potencial de circuito aberto, com vistas à continuidade de pesquisas sobre envelhecimento acelerado. A maioria das propriedades foram medidas por duas repetições, constando os resultados individuais em apêndices. A análise inicial dos resultados dos três lotes foi descritiva e resumiu em tabelas o valor médio, desvio padrão, valor máximo, valor mínimo, a amplitude e o coeficiente de variação de cada lote. As propriedades de cada lote também foram comparadas por análise de variância e, ao final, foram correlacionadas de modo conjunto, independentemente do lote de origem. Nesse caso, foram destacadas as melhores correlações entre propriedades, independentemente dos materiais constituintes de cada concreto. Entre as propriedades do estado fresco, destacaram-se as seguintes: a) o abatimento do tronco de cone apresentou correlação forte e inversa (r² = -0,802, para lotes 1 e 2) com resistência à compressão após um dia de cura acelerada em temperatura moderada, em método similar ao Tipo A da ASTM C 684 (1999); b) o teor de ar pelo método pressométrico apresentou correlações de razoáveis a fortes com a resistência à compressão a 28 dias (r² = -0,698, para lotes 1 e 2), com a resistência à tração por compressão diametral por cura acelerada a sete dias (r² = -0,818, para lotes 1 e 2), com a profundidade de carbonatação em câmara de CO2 (r² = 0,699, para lotes 1 e 2) e com a profundidade de penetração de cloretos por três ciclos de imersão e secagem (r² = 0,625, para lotes 1 e 2); c) as medidas de compactabilidade do concreto adensado, ainda que realizadas em condições de campo, apresentaram várias correlações moderadas com outras propriedades do estado fresco e endurecido. No estado endurecido, destacaram-se as seguintes correlações: a) r² da ordem de -0,75 para a resistência à compressão a um dia dos concretos dos lotes 1 e 2, com cura acelerada de 0/24 horas em temperatura moderada, e a profundidade de carbonatação em câmara de CO2 (5%) e a de penetração de cloretos por três ciclos de imersão e secagem, ambas analisadas a 91 dias, tendo os corpos-de-prova recebido cura inicial acelerada de 24/48 h, em temperatura moderada, seguida de imersão normal por até sete dias; b) r² de -0,682 entre a resistência à tração por compressão diametral, com cura acelerada de 24/48h em temperatura moderada seguida de cura normal por até sete dias, e a profundidade de ingresso de íons cloreto, para os três lotes submetidos aos ciclos citados; c) valores de r² entre 0,521 e - 0,561 para as correlações entre a absorção de água por capilaridade, em corpos-de-prova submetidos à cura inicial acelerada em temperatura moderada por 24/48 h e em temperatura normal por até sete dias, e a resistência à carbonatação para os lotes submetidos aos ciclos citados. Assim, esta pesquisa conclui e propõe que, além do teor de ar no estado fresco, as resistências à compressão e à tração por compressão diametral entre um e sete dias, por cura acelerada do Tipo A da ASTM C 684 (1999) ou por duração adaptada da mesma, sejam propriedades que passem a ser avaliadas em concretos, com vistas a melhorar e controlar a sua resistência a agentes agressivos. Nesta pesquisa, a microestrutura nas primeiras idades do concreto mostrou ser mais determinante da rede de conexão de poros e do transporte de agentes agressivos do que a microestrutura em idades mais avançadas de hidratação; e trabalhos futuros devem confirmar esta interpretação. Espera-se que estes resultados possam estimular novas práticas de qualificação de concretos em estudos de dosagem ou no ato do recebimento de concretos pré-misturados, especialmente em ambientes mais agressivos às armaduras, com vistas à futura evolução de procedimentos da ABNT NBR 12655 (2006). / Durability of reinforced concrete buildings can only be achieved if a set of requirements and criteria is met in the design, execution and maintenance phases, in which the materials must be properly specified, manufactured and employed, according to the respective procedures of these phases. Therefore, the general requirement of protection of carbon steel reinforcements, for structural durability, is contemplated by several criteria as early as the design phase. This thesis addresses the relevant criteria concerning concrete quality and its objective was to contribute to the evolution of technological control procedures for Portland cement structural concretes, in urban and maritime atmospheres in tropical climate, aiming at the protection of carbon steel reinforcements. The experimental program studied three different batches of structural concrete that were similar in terms of slump test basic specifications: 10 ± 2 cm, fck = 30 MPa and class III of ABNT NBR 6118 (2003) environmental classification. The goal was to characterize and analyze the influence of physical properties of fresh concrete on hardened concrete, within the previously mentioned consistency range, with emphasis on those properties related to air content of the mixtures and their respective carbonation and chloride ion penetration resistances. Sampling, fresh concrete tests and specimen molding were conducted during three cast-in-place concretes in two construction sites of multi-storey buildings in the city of João Pessoa, state of Paraíba, in Brazil. The batch plant supplying the concrete for each construction site was responsible for batch composition and production. The initial batch was used to train the team, in the field and laboratory, with a sample of six trucks. The other two batches, identified as 1 and 2, were characterized under very similar conditions, always by the same team, and the samples consisted of five and six trucks, respectively. The properties measured in fresh concrete were: slump test according to Brazilian norm ABNT NBR NM 67 (1998); air content by the pressure method of ABNT NBR 47 (2002); bulk density according to ABNT NBR 9833 (2008); water/dry material ratio by analogy with ABNT NBR 9605 (1992); and compactability of compacted and non-compacted concretes, by adaptation of BS EN 12350-4 (2008). In order to study the properties of hardened concrete, the specimens were cylindrical, measuring 10 cm in diameter and 20 cm in height, and were matured by using two methods adapted from Type A of ASTM C 684 (1999). Some properties were also characterized for normal curing conditions according to ABNT NBR 5738 (2003). The properties studied in hardened concrete were: compressive strength according to ABNT NBR 5739 (2007); splitting tensile strength as per ABNT NBR 7222 (1994); capillary water absorption according to ABNT NBR 9779 (1995); water absorption by immersion and void ratio following ABNT NBR 9778 (2005); carbonation resistance in CO2 chamber (5%; 65 + 10 % RH; 23 + 3 °C); and chloride and CO2 penetration resistance, using three one-day wet and 27-day dry cycles, between seven and 91 days. As a complement, specific steel and concrete specimens were molded to measure open circuit potential, aiming at the continuity of researches on accelerated ageing. Most properties were measured twice and the individual results are presented in appendices. Preliminary analysis of results from the three batches was descriptive and summarized in tables the mean value, standard deviation, maximum value, minimum value, amplitude and coefficient of variation for each batch. The properties of each batch were also compared using analysis of variance and, at the end, were correlated as a whole, regardless of the batch of origin. In this case, the best correlations among properties were highlighted, regardless of the materials used in each concrete. Among the properties of fresh concrete, the following are noteworthy: a) the slump test presented strong and inverse correlation (r² = -0.802, for batches 1 and 2) with compressive strength after one day of accelerated curing at moderate temperature, using a method similar to Type A of ASTM C 684 (1999); b) air content in the pressure method presented reasonable to strong correlations with compressive strength at 28 days (r² = -0.698, for batches 1 and 2), with splitting tensile strength with accelerated curing at seven days (r² = - 0.818, for batches 1 and 2), with carbonation depth in CO2 chamber (r² = 0.699, for batches 1 and 2) and with chloride penetration depth after three immersion-drying cycles (r² = 0.625, for batches 1 and 2); c) compactability measurements of compacted concrete, despite being taken in field conditions, presented several moderate correlations with other properties of fresh and hardened concrete. In hardened concrete, the following correlations should be highlighted: a) r² was -0.75 for compressive strength at one day of the concretes from batches 1 and 2, with 0/24- hour accelerated curing at moderate temperature, and carbonation depth in CO2 chamber (5%) and chloride penetration depth after three immersion-drying cycles, both analyzed at 91 days, after the specimens underwent 24/48-hour initial accelerated curing at moderate temperature, followed by normal immersion for up to seven days; b) r² was -0.682 between splitting tensile strength, with 24/48-hour accelerated curing at moderate temperature followed by normal curing for up to seven days, and chloride ion penetration depth, for the three batches submitted to the aforementioned cycles; c) r² values between 0.521 and - 0.561 for the correlations between capillary water absorption, in specimens submitted to initial accelerated curing at moderate temperature for 24/48h and at normal temperature for up to seven days, and carbonation resistance for the batches submitted to the aforementioned cycles. Therefore, this research concludes and proposes that, besides air content in fresh concrete, compressive strength and splitting tensile strength between one and seven days, using accelerated curing of Type A of ASTM C 684 (1999) or for a duration adapted from that norm, are properties that should be evaluated in concrete, with the purpose of improving and controlling resistance to aggressive agents. In this research, the microstructure of the early ages of concrete proved to be more determinant of the pore structure connection and of the transport of aggressive agents than the microstructure at later ages of hydration; and future studies should confirm this interpretation. It is expected that these results will encourage new practices for the qualification of concrete in mixture proportion studies or when ready mixed concrete is received at construction sites, especially in environments that are more aggressive to reinforcements, with a view to developing future procedures of ABNT NBR 12655 (2006).

Le phénomène de carbonatation des matériaux cimentaires est l'une des causes majeures de la corrosion des armatures de structures en béton armé. Ce phénomène est étudié depuis de nombreuses années sur les ciments Portland ordinaires CEM I, et les mécanismes sont relativement bien identifiés. Néanmoins, on remarque que si l'on substitue une partie du ciment par des ajouts tels que des cendres volantes, la réaction pouzzolanique ou les réactions d'hydratation qui s'en suivront amèneront à un contenu molaire plus faible en CHet aboutiront à la création d'une plus grande quantité d'hydrates de type C-S-H. Le pouvoir tampon qu'exerce la portlandite sur le pH de la solution interstitielle sera affaibli et le matériau cimentaire sera potentiellement plus sensible à la présence de CO2 au travers d'une carbonatation des C-S-H qui sera plus marquée. D'un point de vue physique, les évolutions microstructurales induites par un niveau élevé de carbonatation des C-S-H deviennent complexes et peuvent accélérer la diffusion du CO2. Cette thèse a ainsi pour but de caractériser le comportement vis-à-vis de la carbonatation des ciments contenant de forts dosages en cendres volantes et de développer une modélisation des systèmes cimentaires correspondants. Des pâtes de ciment et mortiers ont été formulés avec des rapports E/C variables et différents taux volumiques de substitution en cendre volante. Après une longue cure endogène, des essais de carbonatation accélérée ont été réalisés (10% de CO2, 25°C et 63% HR). À diverses échéances, des essais destructifs (analyse thermique, porosimétrie au mercure et projection de phénolphtaléine) et non-destructifs (gammadensimétrie) ont permis de quantifier le dioxyde de carbone fixé dans chaque type d'hydrate (CH et C-S-H), les changements de microstructure induits (porosité, distribution poreuse), ainsi que l'eau de structure libérée par carbonatation. On a ainsi pu relier les changements de microstructure et la libération d'eau avec les niveaux de carbonatation de la portlandite et des C-S-H.Dans un second temps, la plateforme de modélisation, Bil (sous licence GPL), développée à l'Ifsttar a été utilisée comme support pour le développement d'un modèle aux volumes finis. Il permet de décrire simultanément des réactions chimiques couplées à un transport de matière. Les lois de comportement chimiques - microstructurales (évolution du volume molaire des C-S-H en fonction de leur état de décalcification) et hydriques (eau relarguée par la carbonatation) mises en évidence par la campagne expérimentale ont pu être ainsi introduites dans le modèle. La cinétique de dissolution de la portlandite est paramétrée par une réduction d'accessibilité des amas de cristaux de CH qui, au cours du temps, se recouvrent d'une gangue de calcite de moins en moins perméable. La contribution des C-S-H est prise en compte. Une approche thermodynamique originale permet de décrire leur état de décalcification à l'équilibre au cours de la carbonatation. Au final, de nombreuses espèces chimiques, ainsi que leur spéciation, sont introduites dans le modèle, notamment les alcalins qui ont un effet marqué sur le pH / Reaction of gaseous atmospheric CO2 with calcium-bearing phases in concrete infrastructure components is known to cause a lowering of alkalinity, leading to depassivation and corrosion of rebars. Carbonation mechanism is quite well understood from a physico-chemical point of view, especially in the case of materials made of OPC. Nonetheless the impact of supplementary cementitious materials (SCM), such as fly-ash, on carbonation is still an active research field. The pozzolanic reaction between CH and fly ash implies a lower portlandite content and a higher C-S-H content. Whilst CH is buffering the pH, its lower content in these materials may lead to a lower resistance to carbonation and to a higher contribution of C-S-H in terms of microstructural changes. Thus, this PhD thesis aims at understanding the effect of cement substitution by high contents of fly ash and develop a numerical model describing the carbonation of these cementitious materials. Accelerated carbonation tests (10% CO2, 25°C and 63% RH) were performed on various cement pastes containing fly ash (0%, 30% and 60% of volumic substitution and water-to-cement ratio before substitution of 0.45 and 0.6). Carbonation profiles were assessed by destructive and non-destructive methods such as thermogravimetric analysis and mercury intrusion porosimetry (destructive), as well as gamma-ray attenuation (non-destructive). Carbonation penetration was studied at different ages of CO2 exposure. By correlating microstructure changes with the degree of carbonation of each hydration product related to the formation of calcium carbonate, we are able to propose analytical relationships linking the decrease in porosity and the amount of released water to the carbonation level of CH and C-S-H.The modeling platform Bil (GPL) developed at Ifsttar was used to develop a reactive transport modeling of atmospheric carbonation, using a finite volume method. We introduced in the model the constitutive equations we highlighted using the experimental data. Microstructure evolution was quantified, taking into account the effect of the progressive decalcification of C-S-H linked to their molar volume, as well as the quantity of water released by carbonation. Combined with a kinetic formulation of CH dissolution, C-S-H decalcification was described by an original thermodynamic approach. In the end, many chemical species were introduced in the model, such as alkalis which strongly affect pH

La carbonatation est une pathologie du béton armé qui peut engendrer la corrosion des armatures et à terme de la fissuration. Dans le cadre de la gestion des déchets radioactifs, les structures et les conteneurs seraient soumis simultanément à un échauffement (exothermie des déchets), au CO2 atmosphérique, ainsi qu'à un séchage important. Afin de rendre compte de leur évolution à l'échelle séculaire, les données actuelles relatives à la carbonatation à température ambiante doivent être complétées, d'une part par une description de la phénoménologie en température, et d'autre part, par la prise en compte de l'impact des transferts hydriques en température (séchage) sur la carbonatation en insaturé. Le travail présenté se focalise sur l’étude de la durabilité de quatre pâtes de ciment différentes dont deux sont directement dérivées des formulations de référence sélectionnées par l’Andra (CEM I et CEM V) et un mélange baspH. Le premier volet est dédié à l'étude des transferts hydriques reposant sur la conduite d'essais de désorption. Il a notamment permis la caractérisation des isothermes de désorption en température (20, 50et 80°C). L'impact thermique modifie les isothermes : la teneur en eau à l’équilibre chute avec la température et le point d'amorçage de la condensation capillaire est déplacé. Une phase de modélisation a conjointement été conduite en support aux expérimentations. L'utilisation de l'équation de Clausius-Clapeyron a permis de décrire l'effet de la température sur les isothermes (par la détermination de la chaleur isostérique d’adsorption de chacun des matériaux). Bien que l'impact de la température sur la microstructure des pâtes de ciment soit avéré, la prise en compte du déplacement des équilibres thermodynamiques suffit à restituer cet effet thermique sur les isothermes. La détermination des perméabilités intrinsèques par exploitation des cinétiques de désorption (par analyse inverse) a montré la thermoactivation du transport d'eau. La contribution de l'évolution de la microstructure en température ne peut-être négligée sur la perméabilité des matériaux.Le deuxième volet exploratoire, est consacré à l'étude de la carbonatation en température. Il repose sur la mise en place d'un dispositif de carbonatation spécifique (fonctionnement en température) et la conduite d'essais de carbonatation à HR et température contrôlées. La campagne de caractérisation (DRX et ATG)a conduit à l'obtention de profils de carbonatation caractéristiques de chaque couple (HR, Température).Les évolutions minéralogiques (décomposition des hydrates, distribution polymorphique du carbonate de calcium précipité) mises en évidence en température se rapprochent de celles identifiées à température ambiante. En revanche, il ressort que les conditions environnementales influencent significativement les proportions polymorphiques : plus l'HR est faible, plus les teneurs en phases métastables (vatérite,aragonite) sont élevées. Les réactions de dissolution-précipitation mises en jeu dans la transformation polymorphique (des états métastables vers la calcite) sont inhibées à faible HR, par manque de milieu réactionnel. La cinétique de carbonatation, également impactée par les conditions environnementales, est régie par la concurrence de l'effet thermique sur les transferts hydriques et sur la solubilité rétrograde des réactifs. Les profondeurs carbonatées sont maximales aux points d'amorçage de la condensation capillaire propres aux différents matériaux et à chaque température. Les profondeurs carbonatées augmentent avec la température jusqu'à une température limite, caractéristique de la formulation, au-delà de laquelle la solubilité rétrograde des réactifs deviendrait le facteur limitant.Cette phase de compréhension des mécanismes mis en jeu dans la carbonatation en température et de leur niveau de couplage effectuée, les modèles prédictifs de carbonatation en insaturé pourront être étendus à l'application en température. Les résultats de ce travail fournissent les données d'entrées et de validation nécessaires à la validation des simulations numériques. / Carbonation is the major cause of degradation of reinforced concrete structures. It leads to rebar corrosion and cracking of the concrete cover. In the framework of radioactive waste management, cement-based materials used as building material for structures or containers would be simultaneously submitted to heating (due to the waste thermal output), subsequent drying and atmospheric carbon dioxide. Such environmental conditions are expected to modify the carbonation mechanisms (with respect to temperature). In order to describe their long-term evolution of material, a double approach was developed, combining the description of carbonation and drying for temperatures up to 80°C to complement available data at ambient temperature. The present work focuses on the durability study off our hardened cement pastes; two of them are derived from the reference formulations selected by Andra(CEM I and CEM V) and a low-pH mix. The first experimental campaign focuses on moisture transfer. The effect of temperature on drying is investigated through water vapour desorption experiments. The first desorption isotherms of four hardened cement pastes was characterized at 20, 50 and 80°C. The results show a significant influence of the temperature. For a given relative humidity (RH) the water content equilibrium is always reduced temperature is increased and the starting point of capillary condensation is shifted towards higher RHs. The experimental campaign is complemented through modelling activities. The impact of temperature on the first desorption isotherms is effectively described using the Clausius-Clapeyron equation(characterization of the isosteric heat of adsorption). The intrinsic permeability to water is evaluated through inverse analysis by reprocessing the experimental weight loss of initially saturated samples submitted to constant environmental conditions. The intrinsic permeability appears to increase with temperature in relation to the observed microstructure evolution (porosity coarsening).The environmental conditions impact is studied using preconditioned samples (12 different RHs and 20,50 and 80°C) and accelerated carbonation tests. The latter are performed in a new device allowing accurate control of the environmental conditions as well as the carbon dioxide concentration. The carbonated depths and the mineralogical modifications induced by carbonation are assessed using XRDand TGA for each temperature and RH. Most of the mineralogical modifications notified in temperature(hydrates consumption and nature of crystallographic phase of calcium carbonate) are similar with these identified at ambient temperature. Yet the results show a significant influence of the environmental conditions on calcium carbonate polymorphic abundance: the lower the RH, the more abundant the metastable phases (vaterite and aragonite).The rate of the polymorphic transformation (from the metastable states into calcite by dissolution precipitation)is believed to decrease with RH because of lack of liquid water. A significant influence of the environmental conditions on the carbonation rate is also observed. It depends of the competition between the temperature effect on moisture transfer and retrograde solubility of reactants. Carbonation depths appear to be maximal at the RH-starting point of capillary condensation of each material and temperature. Carbonation depths increase with temperature until a limit of temperature characteristic of the material. Above this temperature, reactants solubility might control the main process.

L’encrassement biologique des revêtements de façade constitue un problème esthétique et économique. Parmi les microorganismes impliqués, les algues sont les plus répandues. Ce travail avait pour but d’étudier expérimentalement l’influence des paramètres intrinsèques (porosité, rugosité et carbonatation) de mortiers à base de ciment sur leur bioréceptivité et de modéliser le développement du biofilm d’algues.Pour étudier l’effet de ces paramètres sur la biodétérioration des mortiers, un essai accéléré de laboratoire a été développé. Les travaux ont été réalisés avec l’algue verte Klebsormidium flaccidum fréquemment identifiée dans les prélèvements réalisés sur des façades colonisées. Les résultats montrent qu’une augmentation de rugosité et une diminution du pH de surface par carbonatation favorisent l’encrassement des mortiers par les algues.Un modèle inspiré de la loi d’Avrami a permis de modéliser le phénomène de colonisation par les algues. Deux processus interviennent dans le mécanisme de colonisation : l’accrochage (ou « germination ») et la croissance des algues. Les paramètres cinétiques représentant ces processus ont été déterminés et révèlent l’importance de la rugosité et de la carbonatation sur la constante de vitesse de « germination ».L’exposition d’échantillons en extérieur a été également réalisée. Les résultats obtenus permettent de retrouver partiellement le comportement des matériaux en laboratoire même si le démarrage de la colonisation semble être affecté par les conditions climatiques. / Biofouling of wall coatings is an aesthetic and economic problem. Among microorganisms involved, the algae are the most involved. This work aimed to study experimentally the influence of intrinsic parameters (porosity, roughness and carbonation) of a cement-based mortar on its bioreceptivity and to model the development of algae.To study the algal biodegradation, an accelerated laboratory test was developed. This work was carried out with the green alga Klebsormidium flaccidum frequently identified in samples taken on colonized facades. The results show that an increase in roughness and a decrease in surface pH by carbonation of mortars promote fouling by algae.A model based on Avrami's law was used to simulate the algal colonization. Two processes involved in the mechanism of colonization: the attachment (or "germination") and the growth of algae. The kinetic parameters representing these processes have been determined and reveal the importance of the roughness and the carbonation on the constant rate of "germination".Exposure of samples in nature was also carried out. The results obtained allow recovering partially the behavior of materials in the laboratory test even if the start of colonization seems to be affected by weather conditions.

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The main objective of this research is to develop a simple and cost effective separation method that captures carbon dioxide from power plant flue gas, as a pure stream that can be stored using regenerable dolomite (calcium magnesium carbonate) as the sorbent. The developed dolomite sorbent was evaluated for carbon dioxide capture capacity using muti-cycle tests of cyclical carbonation/calcination experiments in the thermogravimetric analyzer (TGA) model SDT 600. The variables controlled in the experiment were weight of calcium oxide and sintering time of the sample. The dolomite materials investigated were from two sources Alfa Aesar and Specialty Minerals. The prepared sorbent, after conditioning, is in the oxide form and can adsorb CO2 to form the carbonate and be regenerated back to the oxide. The results showed that the dolomite sorbent developed can be used for reversible CO2 capture. The data from 8 multi-cycle TGA experiments show that the reversible capacity reduced in the first few cycles; however it stabilized to an average value of 34 percent after an average of 10 cycles and an average conditioning time of 15 hours. Data from two multi-cycle TGA experiments show that the dolomite sorbent is capable of an average stabilized conversion of 65% in an average of 13 cycles at a conditioning time of 87 hours.

Today global warming mitigation, natural resource conservation and energy saving are some of the significant concerns of different industries, such as cement and concrete industries. For that reason, a streamlined life cycle assessment (LCA) model of one ton of a Portland cement, CEM I produced in Cementa AB’s Degerhamn plant, has been developed by using the LCA software KCL-ECO. LCA is a tool that identifies in which stages of a product’s life cycle the most environmental burdens occur. The environmental analysis was limited to identify total energy consumption and total carbon dioxide (CO2) emissions per ton of Portland cement. Results show that the most significant energy consumption and CO2 emissions are related to clinker kiln, due to the process of calcination of limestone and fuel combustion in the kiln. Of total CO2 emissions, 52 % and 46 % result from the calcination process and fuel combustion respectively.  One of the applications of CEM I is in construction of concrete bridges. Therefore an LCA model of a concrete bridge located north of Stockholm was developed in KCL-ECO. Environmental indicators calculated are: total CO2 emissions and energy consumption through the entire life cycle of the bridge. CO2 uptake or carbonation of the concrete during the service life of the product and end of life treatment is one of the advantages of concrete products. During the carbonation process, some of the total CO2 released from calcination will be absorbed into the concrete. Results indicate that production of raw materials and transports during the life cycle of the concrete bridge, are main contributors to total CO2 emissions. Among raw materials, cement production has the highest CO2 emissions. Energy consumption is mainly related to concrete and concrete products production. CO2 uptake during the use phase of the bridge is small compared to total CO2 emissions from calcination. Furthermore, the results show that different waste handling practises result in different CO2 uptake behaviours. The total CO2 uptake from crushing and storing of the demolished concrete (scenario 1) and landfilling of the demolished concrete (scenario 2) is 10 % and 5 % of the total CO2 emissions from calcination respectively.  Since comparison of different construction materials from an environmental point of view is always desirable, the LCA tool was used to compare the total energy consumption and the CO2 emissions from a concrete bridge and a wooden bridge. The functional unit was defined as 1 square meter of bridge surface area, since the bridges were of different sizes and shapes. In this comparison the total emissions and energy consumption were much higher for the concrete bridge than for the wooden bridge.  In order to show how different assumptions could affect the results, a virtual concrete bridge with the same shape and size as the wooden bridge was designed and compared with the wooden bridge. The functional unit selected for this case was one bridge. In this case the virtual concrete bridge requires less energy, while the wooden bridge emits less CO2 to the atmosphere. For the wooden bridge, CO2 in growing forests was included, which could be debated. Overall, a comparison of the environmental performance of the wooden bridge and the concrete bridges was more complex than initially expected and great care is recommended in choosing material and application. With concrete, the design (and quantity of material used) seems to be a very sensitive parameter and may result in much larger energy used and CO2 emissions than a wooden bridge. On the other hand, the virtual bridge comparison showed that concrete advantages such as higher durability and lower maintenance may be theoretically combined with a comparable energy and climate performance as a wooden alternative.

Modern landfills produce landfill gas, LFG, on a smaller scale and with limited content of degradable organic materials in the waste. The waste deposit in the Sofielund landfill began in 2005 and the final coverage is not yet commenced. The landfill waste must contain up to 10% decomposable organic materials at most. In a previous experiment on Sofielund landfill in summer 2011, the measurements from four sample wells showed the landfill gas consisted of up to 45% Methane and about 17000 ppm of Hydrogen sulfide, and the rest was only carbon dioxide. During the earlier experiment in 2011 and during 2012 the smell of H2S got offensive periodically and apart from that, concentrations above 1000 ppm are toxic. Previous research, Bottom ash for biogas upgrading, BABIU, shows that bottom ash from municipal solid waste incinerator (MSWI) can effectively reduce CO­­2 and H2S contents of landfill gas. Bottom ash from MSWI can be utilized in upgrading landfill gas and reduce odor problems of landfills with high H2S production. In this study, an area of 15m x 12m was covered with weathered slag from bottom ash with thickness of about 30cm, to examine how this layer can reduce the concentrations of H2S and CO2. Gas samples were taken from depths of 10cm and 15cm below the surface of bottom ash. There were also samples taken from around the slag-covered area. The surface was laid out 5 days before the first measurement was performed. The experiment was carried out for 20 days, 5, 7, 11, 13, 18 and 20 days after establishment of the surface with bottom ash. The intensity of emissions in different parts of the landfill varied from time to time, due to compacting and changing the permeability of the surface, and it shows that LFG flow in the Sofielund is near the lowest limit of it. Considering the results from the tests in 2011 in deep wells, the recent measurements done in this study showed low contents of LFGs. The highest contents of LFGs in the measurements belong to a pipe, which was found in the waste area of the landfill. Those highest contents of LFG were 15.1% methane, 12.1% carbon dioxide, 0.4% oxygen and the hydrogen sulfide did not exceed 2 ppm. This shows that in deeper depths concentrations of LFG is higher than that of the surface and 10cm below the surface. In the slag covered area CO2 content increased day by day from the first day of the measurement to the last day due to carbonation of the slag and its role in CO2 sequestration.  According to the recent measurement, it can be suggested to cover the landfill with a layer of slag as a construction material, to minimize the LFG emissions and the bad smell from H2S. Therefore it can eliminate direct emissions of LFG to the atmosphere by diffusion through the slag layer. This diffusion allows adsorption of CO2 and oxidation of H2S.

Increasing global temperatures due to anthropogenic emissions of greenhouse gases is one of our times most dire and urgent challenges to overcome if we are to achieve a sustainable healthy planet. The primary way of accomplishing this is by reducing the amount of released greenhouse gases. However, a complementary measure that has been proposed by IPCC (UN, Intergovernmental Panel on Climate Change) to combat this challenge is the carbon dioxide removal technology bio-energy carbon capture and storage (BECCS). This study aims to investigate the suitability of areas located in the south-central part of Sweden for in-situ mineral carbonation, a relatively newly implemented method of permanently storing carbon dioxide in for instance Iceland. The project has been conducted in connection with the research project INSURANCE at Luleå University of Technology (LTU), which has as one of its main objectives to investigate the geological potential for land-based carbon dioxide storage in Sweden. Samples were taken from five different localities in the southern-central part of Sweden: Skutskär, Falun, Öje, Grums, and Åsensbruk. Fifteen representative field samples were then examined with optical microscopy, whole rock geochemistry analysis, scanning electron microscopy (SEM), and micro-XRF in order to characterize the area's bedrock with respect to their potential suitability for in-situ mineral carbonation. The investigations showed that the examined mafic rock units all contained various degrees of metamorphism and alteration, differing them from bedrock in which earlier in-situ mineral carbonation has been successfully tested (Carbfix, Iceland). However, the areas also generally contained considerable amounts of minerals with high Mg, Ca, and Fe ratios, indicating they have a potential for future in-situ mineral carbonation, however, further carbonation experiments are needed to better evaluate the potential.

Although Iron and steel industry is essential for the development of society, the industry is responsible for a large portion of CO2 emissions. The industry also produces by-products like metallurgical slag in orders of million tons. The slag is alkaline in nature and rich in Ca and Mg oxides. Upon use the oxide interact with atmospheric CO2 and form carbonates, making them unstable. Storing CO2 in the slag would make it more stable, enhances its life cycle and promotes further usage in various applications. CO2 sequestration can be done through carbonation of steel slag. Carbonation of slag can be achieved through direct and indirect carbonation. Direct carbonation is performed either in a gaseous or an aqueous state in a single step. Indirect carbonation involves multiple steps as it activates the Ca/Mg ions in the slag before they interact with CO2. For an industrial process the direct route would be more viable as it involves lesser steps, easier to scale up. Since there are no solvents to activate the Ca/ Mg the cost involved is also less. This thesis focuses on developing an industrial process to sequester CO2 in metallurgical slag. Sequestration through a combination of gaseous and aqueous has been attempted while studying the effect of carbonation time, carbonation temperature and shape of slag used. Carbonation of the slag is performed using CO2 and steam. The results show that carbonation yield increases with carbonation time and decreases with increase in temperature. The effect of the shape of slag used for carbonation was studied by performing carbonation test in a slag pellet. Diffusion plays a significant role in carbonation process. Powdered slag showed higher carbonation yield compared to the pellet. CO2 uptake as high as 53g of CO2/kg of slag at 200 oC for 6 hr has been achieved. The results indicate the possibility for an industrial carbonation process. / Även om järn- och stålindustrin är avgörande för samhällets utveckling, är industrin ansvarigför en stor del av koldioxidutsläppen. Industrin producerar också biprodukter som metallurgisk slagg i order på miljoner ton. Slaggen är alkalisk till sin natur och rik på Ca- och Mg-oxider. Vid användning interagerar oxiden med atmosfärisk CO2 och bildar karbonater, vilket gör dem instabila. Att lagra koldioxid i slaggen skulle göra den mer stabil, förbättra livscykeln och främja ytterligare användning i olika applikationer. CO2-bindning kan göras genom kolsyrning av stålslagg. Kolsyrning av slagg kan uppnås genom direkt och indirekt karbonatisering. Direkt karbonatisering utförs antingen i ett gasformigt eller vattenhaltigt tillstånd i ett enda steg. Indirekt kolsyrning involverar flera steg eftersom den aktiverar Ca/Mg-jonerna i slaggen innan de interagerar med CO2. För en industriell process skulle den direkta vägen vara mer livskraftig eftersom den innebär mindre steg, lättare att skala upp. Eftersom det inte finns några lösningsmedel för att aktivera Ca/Mg är kostnaden också mindre. Denna avhandling fokuserar på att utveckla en industriell process för att binda koldioxid i metallurgisk slagg. Sekvestrering genom en kombination av gasformig och vattenhaltig har försökt under undersökning av effekten av kolsyratid, kolsyratemperatur och form av den använda slaggen. Kolsyringen av slaggen utförs med CO2 och ånga. Resultaten visar att karbonatiseringsutbytet ökar med kolsyratiden och minskar med temperaturökningen. Effekten av formen på slagg som användes för karbonatisering studerades genom att utföra karbonatiseringstest i en slaggpellet. Diffusion spelar en viktig roll i karbonatiseringsprocessen. Pulveriserad slagg visade högre karbonatiseringsutbyte jämfört med pelleten. CO2-upptag så högt som 53 g CO2/kg slagg vid 200 oC under 6 timmar har uppnåtts. Resultaten indikerar möjligheten för en industriell karbonatiseringsprocess.