Letteratura scientifica selezionata sul tema "Chlorure. carbonation"
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Articoli di riviste sul tema "Chlorure. carbonation"
1
Xu, Lina, Yan Zhang, Shuyuan Zhang, Shuyuan Fan e Honglei Chang. "Effect of Carbonation on Chloride Maximum Phenomena of Concrete Subjected to Cyclic Wetting–Drying Conditions: A Numerical and Experimental Study". Materials 15, n. 8 (14 aprile 2022): 2874. http://dx.doi.org/10.3390/ma15082874.
Testo completoAbstract (sommario):
The combined action of chloride and carbonation generally accelerates chloride penetration in concrete. Plenty of studies have revealed a chloride maximum phenomenon in the chloride profiles of concrete under wetting and drying cycles, which affects the accuracy of the service life prediction of concrete structures. Carbonation is probably one of crucial factors inducing chloride maximum phenomena. To investigate the influence of carbonation on chloride distribution of concrete subjected to cyclic wetting–drying conditions, this study established a numerical model coupling carbonation effect, simulated chloride distribution at different carbonation degrees, and verified the simulation results with experimental results. The results show that a chloride peak appears in all predicted chloride profiles when carbonation effect is taken into account, and the higher the carbonation degree is, the more significant the chloride peak is. This demonstrates that carbonation can enhance the forming of chloride maximum phenomenon under cyclic wetting and drying. Moreover, the calculated results are highly consistent with the experimental results under different carbonation conditions, especially in terms of the peak chloride concentration and the corresponding depth. Furthermore, the significance degree of the chloride maximum phenomenon is closely related to some key parameters, such as CO2 concentration, environmental humidity, and temperature.
2
Yuan, Yezhen, Kaimin Niu, Bo Tian, Lijuan Kong e Lihui Li. "Effect of Metakaolin on the Diffusion Properties of Chloride Ions in Cement Mortar under the Coupling Effect of Multiple Factors in Marine Environment". Advances in Civil Engineering 2023 (25 maggio 2023): 1–15. http://dx.doi.org/10.1155/2023/6961234.
Testo completoAbstract (sommario):
To address the problem of chloride ion transport in cement concrete in marine environment, this study investigates the effect of metakaolin dosage on the chloride ion diffusion resistance of mortar and its mechanism by testing the chloride ion binding capacity and microstructure of mortar under the coupling effect of chlorine salt-sulfate-carbonation multiple factors. The results show that the coupling of sulfate or carbonation reduces chloride ion transport to some extent compared with single chlorine salt attack, while the three-factor coupled environment promotes free chloride ion diffusion. This is because the products of calcium alumina, gypsum, and calcium carbonate grow together and compete with each other to form more large capillaries; thus, accelerating the diffusion of chloride ions in cement mortar. Metakaolin, due to its higher pozzolanic activity, increases the monocarbon aluminate content in the erosion products, promotes F-salt generation, and increases the Al/Si ratio, which strengthens the binding ability of C-S-H gel to chloride ions, so the free chloride ion concentration inside the specimens doped with metakaolin is lower. In particular, the three-factor coupled environment has less 0.05–10 μm capillary pore content and higher F-salt stability in the specimens, which has the strongest effect on chloride ion curing, and the free chloride ion concentration integral in M-SCCl is reduced by nearly 30% compared with MF-SCCl and F-SCCl.
3
Nakamura, Eisuke, Yuki Kurihara e Hirohisa Koga. "Outdoor Exposure Test of Concrete Containing Supplementary Cementitious Materials". Key Engineering Materials 711 (settembre 2016): 1076–83. http://dx.doi.org/10.4028/www.scientific.net/kem.711.1076.
Testo completoAbstract (sommario):
An outdoor exposure test was conducted to investigate the resistances of concrete containing supplementary cementitious materials (SCMs) to carbonation and chloride ingress at three outdoor exposure testing sites in Japan. The test results indicated that concrete specimens containing larger amounts of SCMs exhibited larger carbonation depths but the carbonation rates decreased as the testing period was extended. Additionally, the resistance to chloride ingress was improved by the use of SCMs in cases where the carbonation depths were negligible. Concrete specimens containing high-volume SCMs, however, showed inverse chloride profiles due to large carbonation depths; chloride contents were low in zones of carbonation but large beyond these zones. The resistance to carbonation was found crucial for preventing reinforcement corrosion induced by not only carbonation but also incidental chloride ingress in concrete containing high-volume SCMs.
4
Chang, Wang, Jin, Li, Feng, Ye e Liu. "Durability and Aesthetics of Architectural Concrete under Chloride Attack or Carbonation". Materials 13, n. 4 (12 febbraio 2020): 839. http://dx.doi.org/10.3390/ma13040839.
Testo completoAbstract (sommario):
Architectural concrete has been wildly used nowadays, and those served in an offshore environment often suffer from chloride penetration and carbonation. To assess the protection and decoration performances of architectural concrete, this study exposed architectural concrete to actual marine environments and accelerated carbonation conditions. The chloride and carbonation resistance of architectural concrete was determined to evaluate the protection performance, and the corresponding surface-color-consistency was adopted to characterize its decoration performance. The results show that the total and free chloride of concrete in the marine atmosphere zone and the tidal zone generally decreases with depth; chloride content arguments significantly with exposure time, with a chloride maximum peak near the surface. Moreover, the chloride diffusion coefficient is small throughout the measurements, indicating the superior chloride resistance of architectural concrete. Furthermore, architectural concrete also possesses excellent carbonation resistance based on the carbonation depth data obtained from the carbonation experiment. Therefore, architecture concrete served as protection covers can withstand both the chloride attack and carbonation tested in this paper. In addition, carbonation was found to have a profound influence on the aesthetics of architectural concrete. Therefore, carbonation should be carefully handled for better maintaining the aesthetic appearance of architectural concrete in long-term service.
5
Chen, Chunhong, Ronggui Liu, Pinghua Zhu, Hui Liu e Xinjie Wang. "Carbonization Durability of Two Generations of Recycled Coarse Aggregate Concrete with Effect of Chloride Ion Corrosion". Sustainability 12, n. 24 (16 dicembre 2020): 10544. http://dx.doi.org/10.3390/su122410544.
Testo completoAbstract (sommario):
Carbonation durability is an important subject for recycled coarse aggregate concrete (RAC) applied to structural concrete. Extensive studies were carried out on the carbonation resistance of RAC under general environmental conditions, but limited researches investigated carbonation resistance when exposed to chloride ion corrosion, which is an essential aspect for reinforced concrete materials to be adopted in real-world applications. This paper presents a study on the carbonation durability of two generations of 100% RAC with the effect of chloride ion corrosion. The quality evolution of recycled concrete coarse aggregate (RCA) with the increasing recycling cycles was analyzed, and carbonation depth, compressive strength and the porosity of RAC were measured before and after chloride ion corrosion. The results show that the effect of chloride ion corrosion negatively affected the carbonation resistance of RAC, and the negative effect was more severe with the increasing recycling cycles of RCA. Chloride ion corrosion led to a decrease in compressive strength, while an increase in carbonation depth and the porosity of RAC. The equation of concrete total porosity and carbonation depth was established, which could effectively judge the deterioration of carbonation resistance of RAC.
6
Yoon, In Seok. "Deterioration of Concrete Due to Combined Reaction of Carbonation and Chloride Penetration: Experimental Study". Key Engineering Materials 348-349 (settembre 2007): 729–32. http://dx.doi.org/10.4028/www.scientific.net/kem.348-349.729.
Testo completoAbstract (sommario):
In most studies, deterioration of concrete due to carbonation or chloride penetration is investigated separately. However, the deterioration of concrete is normally caused by the combination. The purpose of this study is to investigate the interaction between carbonation and chloride penetration and their effects on concrete. This was examined experimentally under various boundary conditions. For concrete under the double condition, the risk of deterioration due to carbonation was not severe. However, it was found that the carbonation of concrete could significantly accelerate chloride penetration. As a result, chloride penetration in combination with carbonation can cause harmful deterioration of concrete.
7
Li, Zhen, Zhen He e Xiaorun Chen. "The Performance of Carbonation-Cured Concrete". Materials 12, n. 22 (12 novembre 2019): 3729. http://dx.doi.org/10.3390/ma12223729.
Testo completoAbstract (sommario):
The research shows that carbonation-cured concrete has several mechanical and durability properties that are better than those of moisture-cured concrete. However, many properties of carbonation-cured concrete have not yet been studied. In this research, carbonation-cured concrete was prepared by pre-curing, carbonation curing, and then moisture curing. The compressive strength, CO2 uptake, pH value, chloride ion permeability and abrasion resistance of the carbonation-cured concrete were investigated. Results showed that the compressive strength of carbonation-cured concrete was more than 10% higher than that of moisture-cured concrete at the same age; a steel bar is stable in carbonation-cured concrete; and carbonation-cured concrete exhibited better abrasion resistance and chloride ion permeability than that of moisture-cured concrete. The optimization of pore structure and improvement in the micro-hardness are the reasons for the improved chloride ion permeability and abrasion resistance of carbonation-cured concrete.
8
Chen, Xiangsheng, e Jun Shen. "Experimental Investigation on Deterioration Mechanisms of Concrete under Tensile Stress-Chloride Ion-Carbon Dioxide Multiple Corrosion Environment". Journal of Marine Science and Engineering 10, n. 1 (8 gennaio 2022): 80. http://dx.doi.org/10.3390/jmse10010080.
Testo completoAbstract (sommario):
The adverse effects of a hostile marine environment on concrete structures inevitably result in great economic loss and may contribute to catastrophic failure. There is limited information on the durability of concrete in a tensile stress-chloride ion-carbon dioxide (TCC) multiple-corrosion environment. The objective of this study is to explore the impact of a TCC multiple-corrosion environment on concrete considering three coupled factors of compressive strength, Cl− penetration, and carbonation. Dry–wet cycle tests were conducted to determine the strength degradation and Cl− penetration concentration of concrete in a hostile multiple-corrosion marine environment. The results show that the effects of water-soluble chloride ions (Cl−), carbon dioxide (CO2), and tensile stress on concrete are not a simple superposition, but involve obvious interaction. The compressive strength of a concrete specimen first increases and then decreases in chlorine salt-carbon tests. The Cl− concentration and tensile stress affect the carbonation depth of concrete, which increases with an increase in Cl− concentration, and with the application of tensile stress. The Cl− concentration has an obvious effect on the carbonation depth. In addition to experimental observations, a stepwise regression equation was established based on the multiple linear regression theory. A correlation analysis considering different factors was conducted to reflect the corrosion results more directly.
9
Zhou, Xiangong, Xiaoyu Zhang, Gang Li e Jialu Li. "Carbonation Characteristics and Bearing Capacity Attenuation of Loaded RC Beam Coupled with Chloride Erosion". Advances in Civil Engineering 2022 (15 luglio 2022): 1–15. http://dx.doi.org/10.1155/2022/5365789.
Testo completoAbstract (sommario):
The durability of a concrete bridge structure is a systematic problem composed of material, structure, natural environment, and service environment. Various factors are coupled, which affect each other, and single-factor research cannot fundamentally solve this problem. In this paper, the carbonation characteristics of RC beams with different loading states under the coupling action of carbonation and chloride erosion are studied. Through the experiment, the author tries to find the influence of stress state and chloride ion erosion on the carbonation of concrete and analyze the failure mode and the attenuation rules of the flexural and shearing capacity of the corroded RC beams under the coupling action. For this purpose, five groups of experiments under different working conditions were designed, including chloride ion erosion and carbonation experiments without external load of the cubic blocks, and chloride erosion and carbonation coupling experiments of RC beams under different stress states and stress levels. The carbonation rate of concrete can be reduced by 56%∼60% under the coupling action of chloride salt. Different loading states and stress levels have an obvious influence on carbonation and chloride ion corrosion, which further affects the corrosion rate of steel bars. Under a low corrosion rate, the bending and shear failure modes of the corroded beams are similar to those of the noncorroded beams, and the section strain distribution still approximately conforms to the plane section assumption. The relationship between the relative ultimate shear strength or the relative ultimate flexural strength and the average section-corrosion rate of the reinforcement is approximately linear.
10
Haibier, Abuduhelili, e Yong Xin Wu. "Effects of Mineral Admixtures on Carbonation and Chloride Ingress of Concrete". Applied Mechanics and Materials 212-213 (ottobre 2012): 878–82. http://dx.doi.org/10.4028/www.scientific.net/amm.212-213.878.
Testo completoAbstract (sommario):
Reinforcement corrosion is one important factor affecting the durability and safety of reinforced concrete structures. Concrete carbonation and chloride ion penetration is the main cause leading to steel corrosion, also important indicators affecting the service life of concrete structures. An accelerated carbonation experiment and Chloride penetration experiment was carried out on ordinary Portland cement (OPC) concrete and admixture concrete in various conditions. Eight concrete specimens of different mixture properties were tested in experiment. Resistance of OPC concrete system with and without mineral admixture (fly ash, slag) and air-entraining agent against carbonation was investigated. Besides, the influence of mineral admixture on the chloride penetration was also studied. The carbonation process and the factors affecting concrete carbonation are discussed according to test results. The test results were presented and they were in good agreement with the results of previous research.
Tesi sul tema "Chlorure. carbonation"
1
Saillio, Mickaël. "Interactions physico-chimiques ions-matrice dans les bétons sains ou carbonatés : influence sur le transport ionique". Thesis, Paris Est, 2012. http://www.theses.fr/2012PEST1033/document.
Testo completoAbstract (sommario):
La carbonatation atmosphérique et la pénétration des ions chlorures sont les principales causes du déclenchement de la corrosion des armatures dans les bétons armés. Chacun de ses mécanismes a fait l'objet de nombreuses études dans la bibliographie. Pourtant les études prenant en compte en même temps les deux types d'agression sont rares. Le couplage des deux phénomènes existe cependant. La carbonatation intervient en effet dans tout ouvrage dès le décoffrage et il suffit que cet ouvrage soit aussi par exemple situé à proximité d'eau de mer pour que les embruns apportent des ions chlorures dans le matériau. L'objectif de cette thèse a été de quantifier les différentes phases de la matrice cimentaire et ses capacités de fixation des ions chlorures par le biais d'isothermes d'interactions pour des matériaux sains et carbonatés. Ces isothermes d'interactions obtenues notamment par la méthode des équilibres ont permis de voir que les matrices partiellement ou totalement carbonatées fixaient moins d'ions chlorures que les matrices saines. L'utilisation de moyens complémentaires d'analyses tels que l'analyse thermogravimétrique (ATG), la diffraction des rayons X (DRX) et la résonance magnétique nucléaire (RMN) a permis de mieux comprendre cette perte de fixation. Une diminution des sels de Friedel et des chlorures fixés par les C-S-H a été ainsi mise en évidence dans les matériaux carbonatés. Ces diminutions qui on été quantifiées sont attribuées à une modification sous carbonatation des phases capables de fixer les ions chlorures (phases aluminates, sulfo-aluminates et C-S-H). Des différences au niveau du réseau poreux ont été également mises en évidence par la porosimétrie par intrusion de mercure (diminution de la macroporosité et de la connectivité en général pour les matrices carbonatées par formation de CaCO3). L'objectif a été aussi de corréler toutes ces modifications observées avec les propriétés de transport des ions qui ont été obtenues par des tests de diffusion et migration des ions chlorures (et/ou sulfates) ainsi que des mesures de résistivité électrique. Les résultats expérimentaux ont montré que le coefficient de diffusion apparent est plus grand dans les matériaux carbonatés. Certaines expériences de diffusion faites en présence à la fois d'ions chlorures et sulfates ont aussi montré la concurrence de ces deux ions pour se fixer à la matrice cimentaire. Les matériaux cimentaires testés (bétons et pâtes) ont été formulés sans ou avec additions minérales (métakaolin, cendres volantes, laitier) et les propriétés de ces matériaux ont été observées à différents âgesCarbonation and chloride ingress are the main causes of reinforced concrete degradation. A lot of studies describe these two phenomena separately but only few studies state a possible coupling. However, the coupling of both phenomena exists. The corrosion of reinforcement due to chloride ions occurs more often in marine environments or in the presence of deicing salts while carbonation occurs systematically, in a more or less high degree depending on environmental conditions (humidity, temperature…). The aim of this thesis was to quantify the different phases of the cement matrix and its chloride binding by means of chloride binding isotherms for carbonated and non-carbonated cement based materials. These chloride binding isotherms, obtained by the equilibrium method, showed that the partially or totally carbonated cement matrix are bound fewer chlorides than the non carbonated ones. Complementary techniques such as the thermogravimetry (TGA), the X-rays diffraction (XRD) and the nuclear magnetic resonance (NMR) analyses were used and allowed to understand why this binding decrease occurs. A decrease of Friedel's salt and chlorides bound in the C-S-H was showed in the carbonated materials. These decreases were quantified and are due to a modification of the phases containing chloride (such as aluminates, sulfo-aluminates and C-S-H phases) during carbonation process. The porous network, was observed by mercury intrusion porosimetry (MIP), was also modified (decrease of the macroporosity and the connectivity for carbonated cement matrix due to formation of calcium carbonate). The other aim was to correlate all these modifications with the ions transport properties. Chloride diffusion and migration tests (with or without sulfates) were obtained as well as the measurements of electric resistivity. The experimental results showed that the apparent chloride diffusion coefficient is higher in the carbonated cement materials. Some diffusion tests were performed in presence of both chlorides and sulfates, which showed the competition of these two ions to bind on the cement matrix. Cement materials (concrete and cement paste) were designed without or with supplementary cementing materials (metakaolin, fly ash, slag) and the properties of these materials were followed at different curing time
2
Tissier, Yolaine. "Etude des processus de corrosion et de la réparation par traitement électrochimique d’extraction des ions chlorure dans les bétons armés doublement contaminés (carbonatation et chlorures)". Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1207/document.
Testo completoAbstract (sommario):
La corrosion des armatures est reconnue comme la première cause de dégradation des structures en béton armé dans les domaines du génie civil et des monuments historiques. La corrosion peut survenir lorsque le béton d'enrobage est carbonaté ou lorsque les ions chlorure sont présents en quantité suffisante au niveau de l'armature.Les objectifs de cette thèse visent à appréhender les processus de corrosion des armatures lorsque le béton est doublement contaminé (carbonatation et ions chlorure) et d'évaluer une solution de réparation de type traitement électrochimique d’extraction des ions chlorure (ECE).Pour répondre à ces objectifs, trois phases ont été programmées : (1) des vieillissements artificiels, (2) un traitement ECE et (3) un suivi de la durabilité du traitement. Pour chacune de ces phases, les évolutions (1) de la corrosion des armatures dans le béton, (2) des produits de corrosion à l'interface armature/béton et (3) de la matrice cimentaire ont été investiguées. L'approche scientifique de l'étude, avec des analyses multiples d'observations à différentes échelles et l'utilisation de techniques non destructives, destructives ou in situ, a permis de rendre compte des processus de corrosion avant et après traitement et de discuter les résultats en fonction de critères d'efficacité proposés.L'étude a été réalisée en prenant en compte deux ciments (CEM I et CEM III/A) et en considérant deux modes de vieillissements artificiels. Trois cent vingt éprouvettes en micro-béton armé répondant à quatre formulations ont ainsi été étudiées. Les techniques principales utilisées sont des caractérisations électrochimiques non destructives, des caractérisations au MEB et EDS, des analyses destructives de déterminations quantitative pour la teneur en ions chlorure et qualitative pour l'évaluation du pH et enfin la microspectrométrie Raman qui permet de déterminer la nature des produits de corrosion in situ.L’exploitation de l’ensemble des résultats a mis en évidence l’évolution des caractéristiques étudiées au cours des phases de l’étude. Avant traitement, l'enrobage béton était entièrement carbonaté et la teneur en ions chlorure libres au voisinage de l'armature était comprise entre 0,9 et 2,1% par rapport à la masse de ciment en fonction des formulations. Les courants de corrosion étaient de l’ordre de 10 µA/cm² et une épaisseur de corrosion homogène de l’ordre de 5-10 µm était observée. Lors des analyses Raman in situ, de la rouille verte chlorurée a été identifiée, synonyme de corrosion active. Après traitement, plus de 90% des ions chlorure ont été extraits et le pH du béton au voisinage de l'armature a augmenté (pH>9) sur une épaisseur d’environ 1 cm. Les courants de corrosion sont devenus inférieurs à 0,1 µA/cm² (niveau de corrosion négligeable). La formation de magnétite a majoritairement été observée avec néanmoins la présence résiduelle très locale de rouille verte. Aucune évolution délétère significative de la matrice cimentaire n’a été identifiée. L’efficacité du traitement a donc été démontrée. L'évaluation de la durabilité du traitement sur une période de 4 à 12 mois a montré que les caractéristiques électrochimiques restaient stables. En revanche, la diminution de l'épaisseur de béton dont le pH avait augmenté pour les éprouvettes fabriquées avec le ciment CEM III/A peut laisser craindre une reprise de corrosion sur du plus long terme. Enfin, le suivi Raman in situ, montre des différences de la durabilité en fonction de la durée du traitementReinforcement corrosion is known as the first cause of reinforced concrete degradation in the fields of civil engineering structures and historical monuments. Corrosion occurs when concrete cover is carbonated or when chloride ions are present in sufficient quantity at the reinforcement vicinity.The main objectives of this thesis are to investigate the corrosion processes of the reinforcement when the concrete is contaminated by carbonation as well as chloride ions and to evaluate a cathodic electrochemical treatment as a repair solution.To meet these objectives, three phases were investigated: (1) artificial agings, (2) an electrochemical chloride extraction (ECE) treatment and (3) durability. For each of these phases, the evolutions (1) of the rebar corrosion in concrete, (2) of the corrosion products at the reinforcement/concrete interface and (3) of the cementitious matrix were studied.The scientific approach gathered multiple analyzes at different scales and the use of non-destructive, destructive or in situ technique. It allowed to study the corrosion processes before and after treatment and to discuss results according to efficiency criteria suggested.The study was carried out taking into account two cements (CEM I and CEM III/A) and considering two modes of artificial aging. More than three hundred specimens of reinforced micro-concrete, corresponding to four concrete designs, were therefore studied. The main techniques used were non-destructive electrochemical characterizations, SEM and EDS characterizations, destructive quantitative determinations (chloride ion content) and qualitative determinations (pH evaluation), and finally Raman microspectrometry to determine the nature of the corrosion products.The results highlighted some evolutions of different characteristics studied during the phases of the study. Before treatment, the concrete cover was entirely carbonated and the free chloride content at the reinforcement level was in the range of 0.9-2.1% by weight of cement depending on the concrete design. A 10 μA/cm² average corrosion currents was reported and a homogeneous corrosion layer thickness of about 5-10 μm was observed. During in situ Raman analysis, chloride green rust was identified indicating an active corrosion.After treatment, more than 90% of the chloride ions were extracted and the thickness of the concrete which had a pH value higher than 9 around the reinforcement, was about 1 cm. The corrosion currents became less than 0.1 μA/cm² (negligible corrosion level). The formation of magnetite was mostly observed with nevertheless a local presence of residual green rust. No significant deleterious evolution of the cementitious matrix was identified. The treatment efficiency was therefore demonstrated. The evaluation of the treatment durability over a period of 4 to 12 months showed that the electrochemical characteristics remained stable. On the other hand, a decrease in the concrete area which pH increased during the electrochemical treatment was observed for CEM III/A cement which could lead to a corrosion recovery over the longer term. Finally, the in situ Raman study revealed differences in durability as a function of the treatment duration
3
Nguyen, Thi Thu Trang. "Influence de l'effet de l'interface acier/béton (top-bar effect) sur la corrosion de structures en béton armé exposées en environnement de chlorures ou de carbonatation". Electronic Thesis or Diss., Université de Toulouse (2023-....), 2024. http://www.theses.fr/2024TLSEI009.
Testo completoAbstract (sommario):
Le béton armé est connu l’un des matériaux les plus utilisés dans la construction. Néanmoins, après une période de mise en exploitation, il peut se corroder. Les chlorures et la carbonatation sont les principaux facteurs provoquant la corrosion des structures en béton armé. La thèse a pour objectif d’étudier le comportement à la corrosion du béton armé sous l’environnement de carbonatation ou des chlorures, correspondant à l'influence de l’effet de la qualité de l’interface acier/mortier (top-bar effet), du type de ciment ainsi que de la fissure transversale artificielle ou des fissures transversales induites par la charge mécanique.En général, la corrosion induite par la carbonatation est étudiée du point de vue de la corrosion uniforme. Le premier objectif de la thèse est de confirmer l’opinion de la corrosion par macro-cellule ou non uniforme dans la corrosion induite par la carbonatation. Selon les résultats expérimentaux, le taux de corrosion dans les armatures de béton carbonaté est susceptible d'être considéré du point de vue de la corrosion uniforme et macro-cellule, qui est fortement influencée par le rapport cathode/anode. De plus, l'application de CEM III utilisant des laitiers comme addition minérale a montré une réduction efficace de la corrosion non uniforme.La deuxième partie se concentre sur l'influence de l’effet de la qualité de l’interface acier/mortier (top-bar effet) sur le comportement de la corrosion dans le cas d'une corrosion induite par la carbonatation et de la présence d'une fissure induite par la charge mécanique. Le suivi du courant de corrosion par macro-cellule a été utilisée dans les essais expérimentaux. Puis la perte de masse ainsi que la cinétique de corrosion ont été calculée. La corrosion s'est développée principalement au niveau du pré-fissures. En raison de l’effet de la qualité de l’interface acier/mortier, les barres supérieures étaient plus corrodées que les barres inférieures. La valeur du courant de la corrosion mesurée sur les barres supérieures a été observée plus élevée que sur les barres inférieures. La perte de masse de l'acier calculée à partir de la mesure du suivi de courant ne correspond qu'à une petite partie de la perte de masse totale déterminée par la mesure gravimétrique. La corrosion uniforme semble être le phénomène principal.La dernière partie étudie l’effet de la qualité de l’interface acier/mortier (top-bar effet) dans des échantillons de béton fibré avec ou sans fissure artificielle sur la corrosion induite par les chlorures. Les barres supérieures sont plus corrodées que les barres inférieures et la partie supérieure de la barre supérieure présente une corrosion plus élevée que la partie inférieure. En présence de fissures artificielles, le ‘’top-bar effet’’ entraîne la propagation de la corrosion le long de la surface des barres d'acier. La corrosion se développe également le long de la barre supérieure lorsqu'il n'y a pas de fissure artificielle, dans un temps pas si différent du cas d'une fissure artificielle. Cela confirme que l'exposition de la surface supérieure et l’effet de la qualité de l’interface acier/mortier sont très préjudiciables à la corrosion. En comparant le comportement avec un béton sans fibres, il apparaît que l'ajout de fibres dans le béton armé entraîne une augmentation de la résistance à la fissuration induite par la corrosion.Dans chaque partie, les observations expérimentales sont couplées à des simulations numériques pour comparer et démontrer les résultats expérimentauxReinforced concrete is known one of the most popular materials applied in construction. Nevertheless after a period of time it can be corroded. Chloride and carbonation are the main factors causing to corrosion in reinforced concrete structure. The thesis aimed to study the corrosion behavior of reinforcement concrete under carbonation or chloride environment, corresponding to the influence of top-bar effect, the cement type as well as artificial transverse crack or load-induced cracks.In general carbonation induced corrosion is usually researched from the point of view that it generates uniform corrosion. The first objective of the thesis is to confirm the opinion of macro cell or non-uniform corrosion in carbonated induced corrosion. According to the results of experiments in this part, corrosion rate in carbonated concrete reinforcement is likely to consider from the point of view of both uniform and macro cell corrosion, which is highly influenced by the ratio cathode/anode. In addition the application of CEM III using slag as addictive exhibited reduction of non-uniform corrosion effectively.The second part focuses on the influence of top-bar effect on corrosion behavior in the case carbonation induced corrosion and presence of load induced crack. Macro cell corrosion current monitoring was utilized in the experiment following the loss of mass as well as corrosion kinetic was calculated. Corrosions mainly developed at the position of the pre-cracks. Due to the top-bar effect upper bars were more corroded than bottom bars. Current corrosion value of top bars was observed higher than bottom bars. Loss of steel mass calculated from macro cell current measurement corresponds to only to a small part of the total loss of mass determined by gravimetric measurement. Uniform corrosion appears to be the main phenomena.The last part investigates the effect of top-bar effect in fibers concrete samples with or without artificial crack on chloride induced corrosion. The top steel bars are more corroded than the bottom bars and the upper part of the top bar is recorded higher corrosion than the lower part. In presence of artificial crack the top casting effect results that corrosions spread along the surface of the steel bars. Corrosion also spread along the top bar when there is no artificial crack, in a time not so different from the case of artificial crack. It confirms that top surface exposure and top bar effect are highly prejudicial for corrosion. By comparing the behavior with concrete without fibers, it appears that the addition of fibers in reinforced concrete leads to an increase of resistance to corrosion induced cracking.For each part, experimental observations are coupled with numerical simulations to compare as well as demonstrate the experimental results
4
Schmitt, Emmanuel. "Approche performantielle et microstructurale de la durabilité de bétons à base de ciments sulfoalumineux-bélitiques ferriques". Thesis, La Rochelle, 2014. http://www.theses.fr/2014LAROS027.
Testo completoAbstract (sommario):
Les ciments sulfoalumineux (CSA) peuvent être une solution à l’amélioration de l’impact environnemental des bétons, grâce aux faibles consommations énergétiques et émissions de CO2 lors de leur fabrication. Leurs propriétés expansives, de rapidité de prise et de montée en résistance participent également à l’intérêt grandissant dans les domaines de la construction et de la préfabrication en béton pour ce type de liant. Toutefois, la durabilité des bétons sulfoalumineux reste encore méconnue ou discutée, notamment en milieux acides et face à la corrosion des armatures, en ambiance marine et par carbonatation. Les travaux présentés dans cette thèse se proposent ainsi d’étudier et de comparer la durabilité face à ces attaques, de bétons sulfoalumineux à celle de bétons de référence à base de CEM I et de CEM III/B. Ils s’appuient sur des caractérisations performantielles (indicateurs de durabilité, essais performantiels en conditions accélérées ou naturelles) et microstructurales (phases solides, porosité). Au préalable, l’application des caractérisations sus-citées aux bétons sulfoalumineux est vérifiée et discutée. La bonne résistance des bétons sulfoalumineux aux milieux acides est observée lors d’essais de lixiviation dynamique, à température et pH régulés. L’étude de la pénétration des chlorures (migration en régime permanent et transitoire, isothermes de fixation, exposition en zone de marnage) et de la carbonatation (naturelle et accélérée) de bétons à base de 8 ciments sulfoalumineux de laboratoire différents a permis d’établir des moyens d’améliorer leur durabilité potentielle. Ces moyens ont été appliqués à la fabrication d’un ciment industriel performant, dont la bonne durabilité reste toutefois à confirmer définitivement en conditions réellesCalcium sulfoaluminate (CSA) cements can be a solution to improve the environmental impact of concrete, thanks to the lower energy consumption and CO2 emission during their production. Their expansive, fast setting and rapid hardening properties contribute to the growing interest of engineers for concrete construction and prefabrication. However, the durability of sulfoaluminate concretes is not clearly assessed yet, especially in acidic and marine environments, as well as carbonation and chloride induced rebars corrosion. Thus, the aim of this thesis is to study and compare the durability, related to these attacks, of concretes made with CSA cements to ordinary Portland and GGBS cements based reference concretes. This study is founded on microstructural (solid phases, porosity) and performancial (durability indicators, natural and accelerated tests) characterization. Beforehand, the application of these characterizations to CSA concretes is verified and discussed. These show a good resistance to acidic environments when submitted to dynamic leaching tests at pH 3 and 5. The study of chloride ingress (steady and non-steady state migration, binding isotherms and tidal zone exposition) and carbonation (natural and accelerated) in concretes of 8 different laboratory CSA cements enabled us to find achievable means to improve their potential durability. These means were applied to the production of a performant industrial CSA cement, whose good durability has still to be assessed on field conditions
5
Salesses, Bernard. "Durabilité des matrices ciment Portland - laitier de haut-fourneau activées par des chlorures". Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30297.
Testo completoAbstract (sommario):
Les laitiers de haut-fourneaux (LHF) sont utilisés dans les ciments notamment en raison de l'amélioration globale de la durabilité qu'ils confèrent aux matériaux de construction. Cependant, les liants à forte teneur en laitiers présentent une hydratation plus lente et donc un développement de résistances mécaniques moins rapide que les ciments portland (CP). Des solutions existent pour accélérer le durcissement des liants à base de LHF, notamment l'emploi d'activants chimiques à base de chlorures. Les effets de l'activation des systèmes CP/LHF sur les développements de résistances mécaniques sont abordés dans la littérature, mais leur durabilité est assez peu étudiée. Cette thèse a donc pour but d'évaluer les conséquences de l'utilisation d'activants chlorés sur la durabilité des liants contenant 50% de LHF. D'abord, une analyse des indicateurs de durabilité permet de voir comment l'activant modifie les propriétés de transfert du matériau durci ainsi que sur la structuration du réseau poreux. Cela permet de vérifier que l'activation à jeune âge n'hypothèque pas la durabilité des bétons avec laitier à long terme. Ensuite, une étude de l'état de corrosion des aciers dans ces mélanges est entreprise afin d'évaluer l'impact des activants chlorés, reconnus pour créer de la corrosion dans le béton armé. Des essais électrochimiques couplés à de l'observation directe ainsi qu'une étude microstructurale sur le devenir des chlorures au sein de la matrice cimentaire est effectuée. La faculté des mélanges à base de laitier à fixer les chlorures dans les hydrates est notamment étudiée. Enfin, le comportement des chlorures fixés est analysé, dans le cas où la carbonatation viendrait déstabiliser les hydrates. L'impact d'un relargage éventuel de chlorures est évalué à l'aide d'un modèle couplé carbonatation/diffusion des chloruresGround granulated blast-furnace slags (GGBS) are used in cements in particular because of the overall improvement in the durability of building materials. However, binders with a high content of GGBS have a slower hydration and thus a development of mechanical strength slower than Portland cements (PC). Solutions exist to accelerate the hardening of GGBS-based binders, including the use of chemical activators based on chlorides. The effects of activation on the mechanical strength developments of PC/GGBS blends are discussed in the literature, but the durability of these systems is not very developed. This thesis aims to evaluate the consequences of the use of chlorides activators on the durability of binders containing 50% of GGBS. Firstly, an analysis of the durability indicators shows how the activator modifies the transfer properties of the hardened material as well as the structuring of the porous network. This allows to verify that the activation at early age does not decrease the long-term durability of concretes with GGBS. Then, a study of the corrosion state of steels in these blends is realized to evaluate the impact of chlorides activators, known to initiate corrosion in reinforced concrete. Electrochemical tests coupled with direct observation as well as a microstructural study on how interact chlorides in the cement matrix are carried out. The ability of GGBS-based blends to bind chlorides in hydrates is studied in particular. Finally, the behavior of binded chlorides is analyzed, in the case where the carbonation would destabilize the hydrates. The impact of a possible release of chlorides is evaluated using a coupled model carbonation / chloride diffusion
6
El, Farissi Anass. "Prédiction de la durée d'utilisation des ouvrages en béton armé par une approche performantielle dans le cas de la corrosion induite par la carbonatation ou l'attaque des ions chlorure". Thesis, La Rochelle, 2020. http://www.theses.fr/2020LAROS025.
Testo completoAbstract (sommario):
La corrosion des armatures en acier est la plus grande cause de défaillance des ouvrages en béton armé. Ce phénomène électrochimique est déclenché par la présence d’ions chlorure en quantité suffisante au niveau de l’armature ou la carbonatation du béton d’enrobage (action du CO2). L’objectif de cette thèse est de développer des modèles utilisables par l’ingénieur dans une démarche d’approche performantielle pour la prédiction de la durée d’utilisation des ouvrages en béton armé soumis à l’attaque par les ions chlorure ou la carbonatation, suite à l’amorçage et au développement de la corrosion en leur sein. Il s’agit du développement de trois modèles : un modèle de transfert des ions chlorure, un modèle de carbonatation et un modèle de corrosion qui permettent d’estimer la durée d’initiation et la durée de propagation de corrosion. Ces modèles prennent en considération les facteurs liés au matériau (i.e. indicateurs de durabilité), à la mise en œuvre, à l’environnement et à la géométrie. La démarche adoptée pour le développement de ces modèles repose sur l’exploitation de plusieurs bases de données, sur des ouvrages vieillissants et des corps d’épreuve de bétons, issues de la littérature (BHP-2000, Perfdub, etc.). Ces exploitations ont permis d’améliorer la capacité prédictive de modèles existants (transfert des ions chlorure) et de développer de nouveaux modèles (carbonatation et corrosion)Steel reinforcement corrosion is the major cause of failure in reinforced concrete structures. This electrochemical process is induced by presence in sufficient quantity of chloride ions at the reinforcement or by concrete carbonation (CO2 action). This thesis aims to develop engineering performance-based models for the service life prediction of reinforced concrete structures subjected to chloride-induced or carbonation-induced corrosion initiation and propagation. It consists in developing three models : a chloride ions ingress model, a carbonation model and a corrosion model that allows to estimate the corrosion initiation time and propagation time. These models consider factors related to the material (i.e. durability indicators), processing, environment and geometry. The approach used to develop these models is based on using several literature databases of ageing structures and concrete testing specimens (BHP-2000, Perfdub, etc.). The use of these data allowed to improve the predictive capacity of existing models (chloride ingress model) and to develop new models (carbonation and corrosion models)
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Hamdan, Ziad. "Evolution de la corrosion des aciers du béton armé en ambiances agressives". Toulouse, INSA, 1993. http://www.theses.fr/1993ISAT0024.
Testo completoAbstract (sommario):
L'experimentation est conduite sur des poutres de beton arme de grandes dimensions, conservees sous charge dans des ambiances agressives: brouillard salin ou atmosphere enrichie en gaz carbonique. L'etat des armatures est suivi periodiquement a l'aide de mesures du potentiel electrochimique (non destructives). Les evolutions de l'endommagement macroscopique et microscopique du beton, de la profondeur de carbonatation et de la penetration des chlorures sont egalement determinees. L'ensemble des observations permet de proposer un modele quadriphasique du processus de corrosion qui prend en compte l'influence de la fissuration de service. La premiere phase dite d'incubation correspond a la penetration des agents agressifs le long des fissures, jusqu'aux armatures. La phase d'initiation debute alors et se traduit par une corrosion localisee en fond de fissures. Lorsque les oxydes formes obstruent le fond des fissures, la corrosion est fortement ralentie: c'est la phase dormante. Durant cette phase, les agents agressifs continuent de penetrer a travers le beton d'enrobage et, lorsque le seuil critique de depassivation est atteint au niveau des armatures, commence la phase de propagation. La corrosion se developpe, conduisant a une fissuration secondaire ramifiee qui contribue a accelerer le phenomene. L'influence du beton d'enrobage est nettement mise en evidence alors que l'ouverture des fissures primaires, qui n'excede pas 0,5 mm dans les poutres experimentees, n'a pas un role determinant. En revanche, l'endommagement des interfaces pate-granulat accelere la penetration des agents agressifs dans les zones tendues des poutres. La comparaison entre les deux ambiances indique que le brouillard salin est plus agressif que l'atmosphere carbonique. De ce fait, le principal parametre a prendre en compte dans la reglementation ne devrait pas etre la seule epaisseur d'enrobage mais un enrobage equivalent integrant le niveau de sollicitation, l'agressivite du milieu et la position des armatures
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Rivera-Corral, Jesus Octavio. "Contribution à l'évaluation de l'état de dégradation de divers types de barres d'acier utilisées comme armatures dans des bétons carbonatés ou pollués par des chlorures". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30210/document.
Testo completoAbstract (sommario):
Le béton armé est sans conteste le matériau le plus utilisé dans la construction, et permet de réaliser la plupart des infrastructures dans tous les pays du monde. Cependant, sa durabilité peut être compromise de façon prématurée par la corrosion des aciers, qui est la pathologie considérée comme la plus dangereuse vis-à-vis du maintien de l'intégrité des ouvrages de Génie Civil. Afin d'obtenir une meilleure résistance face au risque de corrosion, l'acier conventionnel (AC) peut être soumis à divers traitements, dont les plus connus sont le recouvrement superficiel par d'autres matériaux métalliques à base de zinc (AG), ou par des revêtements doubles métal-polymères (AD). Cependant, il existe aussi des barres d'acier thermiquement traitées (ATT) qui ne sont actuellement quasiment pas utilisées en tant qu'armatures. De ce fait, leur comportement face aux mécanismes de détérioration comme la corrosion en milieu cimentaire causée par les chlorures ou la carbonatation est encore très peu connu. Dans ce travail, le comportement des différentes barres d'acier mentionnées ci-dessus a été étudié. Des éprouvettes prismatiques de béton, incluant ces types d'armatures, ont été fabriquées avec deux rapports E/C : 0,45 et 0,65. Avant leur utilisation, les barres ont été caractérisées mécaniquement et métallographiquement. Ensuite, les éprouvettes ont été placées dans différentes conditions d'exposition : un environnement urbain/industriel ou côtier, et un environnement contrôlé en laboratoire. Des mesures du potentiel de corrosion, de résistance de polarisation linéaire, et de spectroscopie d'impédance électrochimique ont été mises en œuvre durant la période d'exposition. Pour chaque série, la teneur critique en chlorures a été déterminée, et la progression de la profondeur de carbonatation a été suivie. En outre, en induisant un couple galvanique par effet de la carbonatation, des mesures originales du comportement électrochimique de ces barres ont été effectuées puis une analyse, en s'appuyant sur une modélisation en éléments finis, en a été faite. Dans l'environnement contrôlé en laboratoire, l'ordre de dépassivation des différentes barres exposées a été observé de façon similaire pour les deux rapports E/C, à savoir : ATT, AC, AG et enfin AD. Une teneur critique en chlorures plus élevée a été obtenue pour les barres AG et AD. Cependant, lors de l'inspection visuelle, les dommages causés sur les armatures AG étaient plus élevés que sur les autres types de barres. Enfin, durant l'étape de propagation, la densité de courant de corrosion des barres ATT et des barres AG s'est révélée inférieureCorrosion of reinforcing bars in concrete is considered as the most important problem that affects the integrity of the civil structures. In order to obtain a better resistance to corrosion, various superficial processes as coatings with zinc (AG) or such as the dual covering metallic-polymeric (AD) are applicate to ordinary steel bars (AC). On the other hand, steel bars with thermal treatments (ATT), principally developed as an alternative to improve the mechanical properties without the use of ferroalloys, are not used in concrete. The behavior of these kinds of bars in front of mechanisms of deterioration as the corrosion induced by chlorides or carbonation has not yet been studied. In this work, all these various steel bars (AG, AD, AC and ATT) were embedded in prismatic specimens of concrete made with two ratio water/cement: 0.45 and 0.65. Previously, steels bars were characterized by mechanical tests and metallographic identifications. Then, specimens were placed in several sites of exposition: urban/industrial environment, or coastal environment, or controlled atmosphere in laboratory. During these expositions, measurements of corrosion potential, linear polarization resistance, and electrochemical impedance spectroscopy were regularly carried out. For each type of steel bar, chloride threshold level and progress of the carbonation depth were determined. Furthermore, by means of the induction of a galvanic couple during design of new samples, the electrochemical behavior of the steels bars AC, ATT and AG was followed up experimentally and then analyzed with finite element model. It was founded that the different steels bars exposed in controlled atmosphere of laboratory followed a same sequence in depassivation for both ratios water/cement: ATT, AC, AG and AD. The chloride thresholds were higher for steels bars AG and AD. However, visual inspection showed that the morphology of damages caused on AG bars was most important compared with the other steel bars. In the propagation phase, the corrosion current density of the ATT bars was lower, even to that obtained by the AG bars
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McCarthy, Michael John. "Chloride and carbonation-induced reinforcement corrosion in PFA concrete". Thesis, University of Dundee, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490143.
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Achour, Mohamad. "Modélisation du couplage carbonatation – chlorures et étude multiéchelle de l’influence des granulats sur la diffusivité dans les bétons". Thesis, Ecole centrale de Nantes, 2018. http://www.theses.fr/2018ECDN0049/document.
Testo completoAbstract (sommario):
La corrosion des aciers est l’une des principales causes de dégradation des ouvrages en béton armé, notamment en façade maritime. Cette dégradation est due à la diffusion d’ions chlorures qui peut se produire dans les ouvrages immergés dans l’eau de mer, ceux subissant des cycles de marnage et également ceux soumis aux embruns marins. La corrosion peut être également due au processus de carbonatation du béton, responsable de la baisse du pH et par conséquent de la dépassivation des aciers. Cette thèse propose un modèle physico-chimique pour décrire la penetration des agents agressifs dans la première phase de la corrosion des aciers. Cette phase dite « incubation » correspond à la phase pendant laquelle le transfert des espèces agressives se produit dans le béton. Afin d’identifier clairement les paramètres de transport de ce modèle macroscopique une démarche multi-échelle est mise en oeuvre pour rendre compte de la diffusion dans les bétons. Cette démarche repose sur une description détaillée de la microstructure du béton (constituants et morphologie) par des méthodes de changement d’échelle. Cette approche se veut la plus exhaustive possible avec la prise en compte explicite de l’influence du rapport eau sur liant de la pâte de ciment, des propriétés des granulats et de la zone de transition entre la pâte et les granulats. Après identification de tous les paramètres d’entrée, le modèle physico-chimique macroscopique est utilisé pour évaluer la durée de vie d’un béton soumis au couplage carbonatation -chlorures en milieu insaturé. Suite à une validation du modèle par comparaison à des résultats expérimentaux, plusieurs applications de ce modèle sont présentéesThe corrosion of steels is one of the principal causes of degradation of reinforced concrete structures, especially in front of the sea. This degradation is due to the diffusion of chloride ions that can occur in the structures immersed in the seawater, those undergoing tidal cycles and also those subjected to the sea spray. The corrosion can also be due to the carbonation process of the concrete, which is responsible for decreasing of the pH and consequently the depassivation of the steels. This thesis proposes a physicochemical model to describe the penetration of aggressive agents in the first period of steel corrosion. This so-called « incubation » period corresponds to the period during which the transfer of aggressive species occurs in the concrete. In order to clearly identify the transport parameters of thismacroscopic model, a multi-scale approach is implemented to consider the diffusion in concretes. This approach is based on taking into account the detailed description of the microstructure of the concrete (constituents and morphology) by upscaling methods. This multi-scale approach is intended to be the most comprehensive with the consideration of the influence of the water-to-binder ratio of the cement paste, the properties of the aggregates and the transition zone between the cement paste and the aggregates. After identifying all the input parameters, the macroscopic physico-chemical model is used to evaluate the service life of a concrete subjected to coupling carbonation -chlorides in unsaturated medium. Following a validation of the model compared to experimental results, several applications of this model are presented
Libri sul tema "Chlorure. carbonation"
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Leonovich, Sergey, Evgeniy Shalyy, Elena Polonina, Elena Sadovskaya, Lev Kim e Valentin Dorkin. Durability of port reinforced concrete structures (Far East and Sakhalin). ru: INFRA-M Academic Publishing LLC., 2021. http://dx.doi.org/10.12737/1816638.
Testo completoAbstract (sommario):
Section I of the monograph is devoted to an urgent problem - forecasting the durability of port reinforced concrete structures, the destruction of which is associated with corrosion of steel reinforcement caused by chloride aggression and carbonation of concrete. The analysis of models for calculating the service life of structures and experimental data is carried out, the life cycles for the main degradation processes in concrete and reinforcement, the periods of initiation and propagation of corrosion are considered, the influence of environmental factors (temperature, humidity) and the quality of concrete (In/C, cement consumption, diffusion coefficient) on the kinetics of chloride penetration and the movement of the carbonation front is taken into account. Probabilistic models of basic variables are considered, the limiting states of port reinforced concrete structures for the durability of reinforced concrete structures based on the reliability coefficient for service life are formulated.
Sections II and III describe modern methods of restoration and restoration of reinforced concrete port structures subjected to corrosion destruction using nanofibrobeton. The concept of multilevel reinforcement has been implemented. Methods of experimental fracture mechanics were used to evaluate the joint work of exploited concrete and reinforcement nanofibre concrete.
It is intended for scientific and engineering staff of universities, research and design organizations.
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W, Hobbs D., e British Cement Association, a cura di. Minimum requirements for durable concrete: Carbonation- and chloride-induced corrosion, freeze-thaw attack and chemical attack. Crowthorne: British Cement Association, 1998.
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3
Ying, Li. Corrosion Of Reinforcement Due To Chloride Ingress & Carbonation. Delft Univ Pr, 2004.
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Gaal, Gerardus Cornelis Maria. Prediction Of Deterioration Of Concrete Bridges: Corrosion Of Reinforcement Due To Chloride Ingress And Carbonation. Delft Univ Pr, 2004.
Cerca il testo completoCapitoli di libri sul tema "Chlorure. carbonation"
1
Saouma, Victor E., e M. Amin Hariri-Ardebili. "Chloride, Carbonation and Corrosion". In Aging, Shaking, and Cracking of Infrastructures, 191–213. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-57434-5_9.
Testo completo
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Mbugua, R., R. Salim e J. Ndambuki. "Effect of Acacia Karroo Gum on carbonation and chloride penetration in concrete". In Insights and Innovations in Structural Engineering, Mechanics and Computation, 1558–61. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2016. http://dx.doi.org/10.1201/9781315641645-256.
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Yoon, In Seok. "Deterioration of Concrete Due to Combined Reaction of Carbonation and Chloride Penetration: Experimental Study". In Advances in Fracture and Damage Mechanics VI, 729–32. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-448-0.729.
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Tiwari, Ashish Kumar, Sunil Garhwal, Anil Garhwal e Anirban Banik. "Inhibition Performance of Generic Compounds as Corrosion Inhibitor in Combined Chloride and Carbonation Environment". In Intelligent Computing and Optimization, 270–78. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-50151-7_26.
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Bastidas-Arteaga, Emilio, e Mark G. Stewart. "Climate change impact on RC structures subjected to chloride ingress and carbonation-induced corrosion". In Routledge Handbook of Sustainable and Resilient Infrastructure, 626–45. Abingdon, Oxon ; New York, NY : Routledge, 2019. |: Routledge, 2018. http://dx.doi.org/10.4324/9781315142074-32.
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Liu, Huamou, Wanyun Lu e Guoming Liu. "Study on controlling the effect of chloride salt erosion and carbonation on the deterioration of shotcrete". In Atlantis Highlights in Engineering, 180–96. Dordrecht: Atlantis Press International BV, 2024. http://dx.doi.org/10.2991/978-94-6463-435-8_22.
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Dang, Quoc Viet, Aoi Okada, Yuko Ogawa e Kenji Kawai. "Influence of Chloride Ion in Sea Sand on Mechanical Properties of Fly Ash Concrete Exposed to Accelerated Carbonation". In Lecture Notes in Civil Engineering, 521–29. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-5144-4_48.
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Lima, Lucas, Timothy Wangler, Asel Maria Sanchez, Ana Anton e Robert J. Flatt. "Durability of 3D Printed Concrete: Performance Assessment of a Two-Component System Against Water Absorption, Carbonation, and Chloride Ingress". In RILEM Bookseries, 291–98. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-70031-6_34.
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Lizarazo-Marriaga, Juan, Luis Felipe Salazar-Mayorga e Luis Eduardo Peña-Cruz. "Carbonation or Chloride Ingress? Which One is the Durability Key Factor in Low Reactivity Clay and Limestone Blended Concrete". In International RILEM Conference on Synergising Expertise towards Sustainability and Robustness of Cement-based Materials and Concrete Structures, 899–910. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-33187-9_82.
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Vanoutrive, Hanne, Peter Minne, Özlem Cizer e Elke Gruyaert. "The Impact of Chloride Binding on the Resistance to Carbonation: From Single Cycle Degradation Towards the Complexity of Multi Cycle Degradation". In International RILEM Conference on Synergising Expertise towards Sustainability and Robustness of Cement-based Materials and Concrete Structures, 1095–103. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-33187-9_101.
Testo completoAtti di convegni sul tema "Chlorure. carbonation"
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Andrade, C. "Carbonation Effect on the Chloride Profile". In XV International Conference on Durability of Building Materials and Components. CIMNE, 2020. http://dx.doi.org/10.23967/dbmc.2020.232.
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Wang, Y. C., P. A. M. Basheer, S. Nanukuttan e Y. Bai. "Progress of Carbonation in Chloride Contaminated Concretes". In International Conference on the Durability of Concrete Structures. Purdue University Press, 2016. http://dx.doi.org/10.5703/1288284316151.
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SAEKI, T. "Effect of carbonation on chloride penetration in concrete". In Third International RILEM Workshop on Testing and Modelling Chloride Ingress into Concrete. RILEM Publications SARL, 2005. http://dx.doi.org/10.1617/2912143578.025.
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Heirman, G. "Chloride penetration and carbonation in self-compacting concrete". In ConcreteLife'06 - International RILEM-JCI Seminar on Concrete Durability and Service Life Planning: Curing, Crack Control, Performance in Harsh Environments. RILEM Publications SARL, 2006. http://dx.doi.org/10.1617/291214390x.002.
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"Chloride Ions Penetration and Carbonation in Alkaline Activated Slag". In SP-326: Durability and Sustainability of Concrete Structures (DSCS-2018). American Concrete Institute, 2018. http://dx.doi.org/10.14359/51711006.
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Li, Guo, Xiaoling Li, Rongrong Wei, Jianmin Du e Xiaosuo Wu. "Concrete Carbonation and Chloride Resistance Under Initial Hot Water Curing". In International Conference on the Durability of Concrete Structures. Purdue University Libraries Scholarly Publishing Services, 2014. http://dx.doi.org/10.5703/1288284315383.
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Bhowmik, Sonali, e Ram Lal Riyar. "Carbonation And Chloride-Induced Corrosion Fatigue Life Prediction Of Reinforced Concrete". In 11th International Conference on Fracture Mechanics of Concrete and Concrete Structures. IA-FraMCoS, 2023. http://dx.doi.org/10.21012/fc11.0923105.
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Cho, Yung-Zun, In-Tae Kim, Hee-Chul Yang, Hee-Chul Eun, Hwan-Seo Park e Eung-Ho Kim. "Removal of Alkaline-Earth Elements by a Carbonate Precipitation in a Chloride Molten Salt". In The 11th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2007. http://dx.doi.org/10.1115/icem2007-7288.
Testo completoAbstract (sommario):
Separation of some alkaline-earth chlorides (Sr, Ba) was investigated by using carbonate injection method in LiCl-KCl eutectic and LiCl molten salts. The effects of the injected molar ratio of carbonate ([K2 (or Li2)CO3/Sr (or Ba)Cl2]) and the temperature (450–750 °C) on the conversion ratio of the Sr or Ba carbonate were determined. In addition, the form of the Sr and Ba carbonate resulting from the carbonation reaction with carbonates was identified via XRD and SEM-EDS analysis. In these experiments, the carbonate injection method can remove Sr and Ba chlorides effectively over 99% in both LiCl-KCl eutectic and LiCl molten salt conditions. When Sr and Ba were co-presented in the eutectic molten salt, they were carbonated in a form of Ba0.5Sr0.3CO3. And when Sr was present in LiCl molten salt, it was carbonated in the form of SrCO3. Carbonation ratio increased with a decreasing temperature and it was more favorable in the case of a K2CO3 injection than that of Li2CO3. Based on this experiment, it is postulated that carbonate precipitation method has the potential for removing alkali-earth chlorides from LiCl-KCl eutectic and LiCl molten salts.
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Claude, P., F. Duprata, T. de Larrarda, J. Mai-Nhub, P. Rougeaub, L. Marraccic e P. Guédon. "Probabilistic Approach for Concrete Structures Exposed to Combined Carbonation-chloride-induced Corrosion". In 32nd European Safety and Reliability Conference. Singapore: Research Publishing Services, 2022. http://dx.doi.org/10.3850/978-981-18-5183-4_r28-02-165.
Testo completo
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Claude, P., F. Duprata, T. de Larrarda, J. Mai-Nhub, P. Rougeaub, L. Marraccic e P. Guédon. "Probabilistic Approach for Concrete Structures Exposed to Combined Carbonation-chloride-induced Corrosion". In 32nd European Safety and Reliability Conference. Singapore: Research Publishing Services, 2022. http://dx.doi.org/10.3850/978-981-18-5183-4_r28-02-165-cd.
Testo completoRapporti di organizzazioni sul tema "Chlorure. carbonation"
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Desbarats, A. J., e J. B. Percival. Hydrogeochemistry of mine tailings from a carbonatite-hosted Nb-REE deposit, Oka, Quebec, Canada. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331256.
Testo completoAbstract (sommario):
Environmental impacts associated with the mining of carbonatite deposits are an emerging concern due to the demand for critical metals. This study investigates the chemistry of tailings seepage at the former Saint Lawrence Columbium mine near Oka, Québec, Canada, which produced pyrochlore concentrate and ferroniobium from a carbonatite-hosted Nb-REE deposit. Its objectives are to characterize the mineralogy of the tailings and their pore water and effluent chemistries. Geochemical mass balance modeling, constrained by aqueous speciation modeling and mineralogy, is then used to identify reactions controlling the chemical evolution of pore water along its flow path through the tailings impoundment. The tailings are composed mainly of REE-enriched calcite (82 wt. %), biotite (12 wt. %) and fluorapatite (4 wt. %). Minor minerals include chlorite, pyrite, sphalerite, molybdenite and unrecovered pyrochlore. Secondary minerals include gypsum, barite and strontianite. Within the unsaturated zone, pore water chemistry is controlled by sulfide oxidation and calcite dissolution with acid neutralization. With increasing depth below the water table, pore water composition reflects gypsum dissolution followed by sulfate reduction and FeS precipitation driven by the oxidation of organic carbon in the tailings. Concomitantly, incongruent dissolution of biotite and chlorite releases K, Mg, Fe, Mn, Ba and F, forming kaolinite and Ca-smectite. Cation exchange reactions further remove Ca from solution, increasing concentrations of Na and K. Fluoride concentrations reach 23 mg/L and 8 mg/L in tailings pore water and effluent, respectively. At a pH of 8.3, Mo is highly mobile and reaches an average concentration of 83 µg/L in tailings effluent. Although U also forms mobile complexes, concentrations do not exceed 16 µg/L due to the low solubility of its pyrochlore host. Adsorption and the low solubility of pyrochlore limit concentrations of Nb to less than 49 µg/L. Cerium, from calcite dissolution, is strongly adsorbed although it reaches concentrations (unfiltered) in excess of 1 mg/L and 100 µg/L in pore water and effluent, respectively. Mine tailings from carbonatite deposits are enriched in a variety of incompatible elements with mineral hosts of varying reactivity. Some of these elements, such as F and Mo, may represent contaminants of concern because of their mobility in alkaline tailings waters.