Academic literature on the topic 'Mechanical carbonation'
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Journal articles on the topic "Mechanical carbonation"
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Wang, Jia Bin, Di Tao Niu, Rui Ma, and Ze Long Mi. "Influence the Carbonation Resistance and Mechanical Properties of Shotcrete by Accelerated Carbonation Test." Advanced Materials Research 1065-1069 (December 2014): 1985–89. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.1985.
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In order to investigate the carbonation resistance of shotcrete and the mechanical properties after carbonation, the accelerated carbonation test was carried out. The results indicate that the carbonation resistance of shotcrete is superior to that of normal concrete. With the increasing of carbonation depth, compressive strength and splitting tensile strength of shotcrete grew rapidly. The admixing of steel fiber can further improve the carbonation resistance, reduce the carbonation rate, and increase the splitting tensile strength of shotcrete greatly. Besides, based on analyzing the effects of construction technology and steel fiber of concrete for the carbonation resistance, a carbonation depth model for shotcrete was established. Key words: shotcrete; carbonation; steel fiber; mechanical properties
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Wu, Qi Sheng, Hong Xia Gu, Tao Yang, Chang Sen Zhang, Zhi An Min, and Yang Wu. "Analysis of Mechanical Performance and Microstructure of Steel Slag Processed with Accelerated Carbonation." Materials Science Forum 944 (January 2019): 1240–51. http://dx.doi.org/10.4028/www.scientific.net/msf.944.1240.
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The accelerated carbonation with different pressure steaming conditions was used to process the steel slag, so the slag could turn into a primary cementitious product with carbonation activity. XRD, FTIR, TG, N2 absorption BET surface area analyzer and SEM were used to characterize the mineral and chemical compositions and microstructure of each sample before and after the carbonation. The results show that: the carbonation products with different morphologies are formed under different temperature conditions. The optimum temperature for the accelerated carbonation for processing the steel slag is selected to be 90 °C, which results in the compressive strength of 32.8 MPa. The BET specific surface area of the steel slag reduces after carbonation, the sample density increased after carbonation.
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Wang, Weikang, Xuanchun Wei, Xinhua Cai, Hongyang Deng, and Bokang Li. "Mechanical and Microstructural Characteristics of Calcium Sulfoaluminate Cement Exposed to Early-Age Carbonation Curing." Materials 14, no. 13 (June 24, 2021): 3515. http://dx.doi.org/10.3390/ma14133515.
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The early-age carbonation curing technique is an effective way to improve the performance of cement-based materials and reduce their carbon footprint. This work investigates the early mechanical properties and microstructure of calcium sulfoaluminate (CSA) cement specimens under early-age carbonation curing, considering five factors: briquetting pressure, water–binder (w/b) ratio, starting point of carbonation curing, carbonation curing time, and carbonation curing pressure. The carbonization process and performance enhancement mechanism of CSA cement are analyzed by mercury intrusion porosimetry (MIP), thermogravimetry and derivative thermogravimetry (TG-DTG) analysis, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results show that early-age carbonation curing can accelerate the hardening speed of CSA cement paste, reduce the cumulative porosity of the cement paste, refine the pore diameter distribution, and make the pore diameter distribution more uniform, thus greatly improving the early compressive strength of the paste. The most favorable w/b ratio for the carbonization reaction of CSA cement paste is between 0.15 and 0.2; the most suitable carbonation curing starting time point is 4 h after initial hydration; the carbonation curing pressure should be between 3 and 4 bar; and the most appropriate time for carbonation curing is between 6 and 12 h.
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Babalola, O. E., Paul O. Awoyera, D. H. Le, Oladimeji B. Olalusi, and S. K. Bhagat. "Anthropogenic Carbon Aerosol Induced Carbonation in Reinforced Concrete: Deterioration Effects on Mechanical Properties." International Journal of Engineering Research in Africa 57 (November 9, 2021): 139–48. http://dx.doi.org/10.4028/www.scientific.net/jera.57.139.
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The effects of corrosion on the reinforced concrete structure due to carbonation affect its operation life. The research work considers a major critical component causing global warming as it studies the links between reinforced concrete deterioration mechanisms and anthropogenic carbon aerosol (black carbon soot) emissions in the atmosphere. Experimental tests were carried out to study the effect of carbonation caused by the emission of black carbon soot on mechanical properties and durability of reinforced concrete. Mass concrete and reinforced concrete prepared with Ordinary Portland cement (OPC) in water/cement ratios ranging from 0.45 to 0.65 were used to produce concrete samples. Compressive strength tests, tensile strength test, and carbonation depth tests were carried out on concrete to determine its level of deterioration following the carbonation effect. The carbonation chamber was prepared with carbon soot of different concentrations to simulate different levels of black carbon soot in the atmosphere. Results showed that concrete compressive strength was not totally affected by carbonation, but there was reduction in the tensile strength of reinforcing steel. The carbonation depth was observed to progress deeper into the concrete with a longer duration of exposure to carbonation agents in the chamber. The result of this study will serve as a guide during concrete installations.
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Unluer, Cise. "Investigating the Carbonation and Mechanical Performance of Reactive MgO Cement Based Concrete Mixes." Nano Hybrids and Composites 19 (February 2018): 23–33. http://dx.doi.org/10.4028/www.scientific.net/nhc.19.23.
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Carbonation governs the microstructure and the overall mechanical performance of mixes involving MgO cements as the main binder. Aggregate grading has a significant influence on the carbonation process due to the different particle arrangements that determine the porosity and permeability of the resulting formulations. This work investigates the effect of aggregate particle size distribution on the carbonation of blocks containing reactive MgO. Samples containing four different aggregate profiles were subjected to accelerated carbonation at 20% CO2 concentration for up to 28 days. While the influence of gap grading on strength development was not very pronounced, mixes with the lowest initial porosity indicated the greatest increase in density at the end of 28 days. This also translated into the highest strength results obtained due to the formation of hydrated magnesium carbonates, reaching 10 MPa only after 1 day of carbonation. The porosity values measured before carbonation were inversely correlated with the corresponding densities and final strengths of each mix. An inverse correlation between porosity and permeability values before carbonation led to the conclusion that the connectivity of pores rather than the total pore volume controls the carbonation reaction. Mixes with higher initial permeabilities achieved the highest strengths, proving that the extent of CO2 diffusivity is mainly dependent on pore connectivity.
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Kim, Hayeon, and Hyeongmin Son. "Utilization of Bio-Mineral Carbonation for Enhancing CO2 Sequestration and Mechanical Properties in Cementitious Materials." Buildings 12, no. 6 (May 30, 2022): 744. http://dx.doi.org/10.3390/buildings12060744.
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Microorganisms can perform mineral carbonation in various metabolic pathways, and this process can be utilized in the field of construction materials. The present study investigated the role of bio-mediated mineral carbonation in carbon sequestration performance and mechanical properties of cementitious materials. Bacterial-mediated ureolysis and CO2 hydration metabolism were selected as the main mechanisms for the mineral carbonation, and a microorganism, generating both urease and carbonic anhydrase, was incorporated into cementitious materials in the form of a bacterial culture solution. Four paste specimens were cured in water or carbonation conditions for 28 days, and a compressive strength test and a mercury intrusion porosimetry analysis were performed to investigate the changes in mechanical properties and microstructures. The obtained results showed that the pore size of the specimens incorporating bacteria was reduced by the precipitation of CaCO3 through the mineral carbonation process, thereby improving the mechanical properties of the paste specimens, regardless of the curing conditions. In addition, in the case of the paste specimens cured in carbonation conditions, more amorphous CaCO3 was observed and a larger amount of CaCO3 in the specimens incorporating the bacteria was measured than in the specimens without bacteria. This is attributed to promotion of the inflow and diffusion of CO2 via mineral carbonation through bacterial CO2 hydration metabolism.
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Kim, Jung J., Kwang-Soo Youm, and Jiho Moon. "A Study on Conversion Fraction and Carbonation of Pozzolan Blended Concrete through 29Si MAS NMR Analysis." Applied Sciences 10, no. 19 (September 29, 2020): 6855. http://dx.doi.org/10.3390/app10196855.
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The object of this paper is to investigate the carbonation resistance of concretes containing different pozzolanic materials. Three concrete mixtures that included fly ash, silica fume, and nanosilica were prepared, and the mixtures were designed to have similar mechanical properties to exclude the effect of mechanical properties on the carbonation. These pozzolanic materials in concretes have different silicate contents and grain size distributions. Rapid carbonation tests were conducted to investigate the durability of pozzolan blended concretes for carbonation, and the carbonation depth was measured at one, two, four, and eight weeks after 28-day water curing. 29Si NMR (nuclear magnetic resonance) experiments were performed, and the conversion fractions for each pozzolan blended concrete were extracted. The degree of carbonation was also assessed based on the Nuclear magnetic resonance (NMR) results.
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Liu, Zhiyuan, Philip Van den Heede, and Nele De Belie. "Effect of the Mechanical Load on the Carbonation of Concrete: A Review of the Underlying Mechanisms, Test Methods, and Results." Materials 14, no. 16 (August 6, 2021): 4407. http://dx.doi.org/10.3390/ma14164407.
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As one of the major causes of concrete deterioration, the carbonation of concrete has been widely investigated over recent decades. In recent years, the effect of mechanical load on carbonation has started to attract more attention. The load-induced variations in crack pattern and pore structure have a significant influence on CO2 transport which determines the carbonation rate. With different types of load, the number, orientation, and position of the induced cracks can be different, which will lead to different carbonation patterns. In this review paper, the carbonation in cracked and stress-damaged concrete is discussed first. Then, literature about the effect of sustained load during carbonation is compared in terms of load type and load level. Finally, the advantages and disadvantages of possible test methods for investigating the effect of sustained load on carbonation are discussed with respect to loading devices, load compensation, and specimen size.
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C. M., Ikumapayi, Adeniji A. A., Obisesan A. A., Odeyemi O., and Ajayi J. A. "Effects of Carbonation on the Properties of Concrete." Scientific Review, no. 512 (December 5, 2019): 205–14. http://dx.doi.org/10.32861/sr.512.205.214.
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Concrete is one of the reliable, durable, economical and acceptable construction materials among the building and construction stakeholders worldwide. Performance of concrete could be threatened especially reinforced concrete by some processes such as corrosion, sulfate attack among others. Corrosion of reinforcement in reinforced concrete can be induced by carbonation process. Even though carbonation initiates corrosion, it has been gathered that carbonation could still be of immense benefits to building and construction industries if its mechanism of operation is understudied. This research work has therefore investigated the effect of carbonation on some selected mechanical properties of concrete such as compressive strength, flexural strength, water absorption and weight changes. Concrete cubes and beams of M15 grade with 0.5 % water-cement ratio were prepared and subjected to accelerated carbonation. Their compressive strength, flexural strength, water absorption and weight changes were determined in accordance with the relevant standards. The outcomes show that carbonation improves all the mechanical properties investigated. The use of carbonation can be positively explored in reinforced concrete provided there is adequate nominal cover.
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Li, Zhen, Zhen He, and Xiaorun Chen. "The Performance of Carbonation-Cured Concrete." Materials 12, no. 22 (November 12, 2019): 3729. http://dx.doi.org/10.3390/ma12223729.
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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.
Dissertations / Theses on the topic "Mechanical carbonation"
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Li, Jiajie. "Mechanical activation of ultramafic mine waste materials for enhanced mineral carbonation." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61039.
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The potential success of integrating mineral carbonation, as a pathway to CO₂ sequestration, in mining projects, is dependent on the mineralogical composition and characteristics of its waste rock and tailings. Ultramafic rocks have proven the best potential substrate for mineral carbonation and their ability to alter and to convert CO₂ into its carbonate mineral form is dependent on the original mineralogy and particle surface area. CO₂ conversion kinetics is complex and with the application of appropriate comminution technologies, its efficiency can be enhanced. The objective of this research is to evaluate mechanical activation to enhance the carbonation storage capacity of mine waste material. Three approaches were taken in this research. The first approach was to characterize the microstructure of the mechanically-activated mineral olivine, a predominant mineral constituent of ultramafic rocks, using X-ray diffraction patterns and line profile analysis methods with full pattern fitting method. The second approach was to compare the structural and chemical changes of mine waste with pure olivine, both of which were activated by various mechanical forces under both wet or dry conditions and subsequently carbonated in a direct aqueous carbonation process. Regardless of milling conditions, forsterite (Mg₂SiO₄), the olivine mineral variety in the mine waste, was found to be the main mineral being mechanically-activated and carbonated. It was determined that lizardite (Mg₃(Si₂O₅)(OH)₄), a hydrated magnesium silicate also common in ultramafic hosted mineral deposits, acted as catalyzer assisting forsterite reaching high levels of activation. This condition generated a greater CO₂ conversion to carbonate than that of pure olivine with the equal specific milling energy input. The stirred mill proved to be the most efficient form of mechanical activation vis-a-vis the direct aqueous carbonation process, followed by the planetary mill and the vibratory mill. The third approach analyzes the feasibility of mechanical activation in an integrated mineral carbonation process in a nickel mine considering the life cycle of the process. The minimum operating cost for 60% CO₂ sequestration efficiency was 105-107 $/t CO₂ avoided. At this point, the Turnagain project can potentially sequester 238 Mt/y CO₂ using its waste during the 28-year life of mine.Applied Science, Faculty of
Mining Engineering, Keevil Institute of
Graduate
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Suazo, Franco Josue Amaya. "Efeito da carbonatação em compósitos cimento-pó de coco." Universidade Federal de Sergipe, 2016. https://ri.ufs.br/handle/riufs/3525.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESThis work comprises two studies on the evaluation of cement-coconut powder composite in curing and aging conditions. In the first study the composites were subjected to the accelerated carbonation process during the first 48 hours of cure, then were dried and subjected to curing conditions until saturated at 28 days. The results shows that the composites had a reduction in the water absorption and increased bulk density. The carbonated composites had a 26% increase in compression strength and 16% in the flexural strength as compared to no-carbonate composite. The interaction between the reduction of the Ca(OH)2 and increasing CaCO3 content was observed by thermogravimetric analysis. In the second study, the composites was evaluated by methods of external and internal natural aging for 6 months and by the accelerated carbonation for 84 days. Increased measurements from electrical resistivity and ultrasonic during cure age were related to the increase in the mechanical properties, reduction of porosity and hydration process of these composites. Three types of age showed similar mechanical and physical properties, the electrical resistivity measurements was related to the increase of CaCO3 content, verified by thermogravimetry. The different stages of this work the composites were characterized by X-ray diffraction, thermal analysis, scanning electron microscopy with energy dispersive spectroscopy and were evaluated for their physical and mechanical properties.
Este trabalho compreende dois estudos sobre a avaliação de compósitos cimento-pó de coco em condições de cura e de envelhecimento. No primeiro estudo, os compósitos foram submetidos ao processo de carbonatação acelerada durante as primeiras 48 horas de cura e, em seguida foram submetidos as condições de cura seca e saturada até 28 dias. Os resultados indicaram que os compósitos carbonatados tiverem uma absorção de água reduzida e aumento da densidade. Esses materiais apresentaram um aumento de 26% na resistência à compressão e de 16% no módulo de ruptura, em comparação com compósitos não carbonatados. A interação entre a diminuição do conteúdo de Ca(OH)2 e o aumento do teor de CaCO3 foi observada por análise termogravimétrica. No segundo estudo, os compósitos foram avaliados pelos métodos de envelhecimento natural externo e interno por até 6 meses, e pela carbonatação acelerada por até 84 dias. O aumento das medições de resistividade eléctrica e de ultrassom durante o período de cura foi relacionado com o aumento nas propriedades mecânicas, redução da porosidade e o processo de hidratação dos compósitos. Os três tipos de envelhecimento apresentaram propriedades físicas e mecânicas similares, as medidas de resistividade elétrica foram relacionadas com o aumento do teor de CaCO3 comprovado pela termogravimetria. Nas diferentes etapas do presente trabalho, os compósitos foram caracterizados por difração de raios X, análise térmica, microscopia eletrônica de varredura com espectroscopia por dispersão de energia e foram avaliadas as suas propriedades físicas e mecânicas.
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Eiras, Fernández Jesús Nuño. "Studies on nonlinear mechanical wave behavior to characterize cement based materials and its durability." Doctoral thesis, Universitat Politècnica de València, 2016. http://hdl.handle.net/10251/71439.
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[EN] The test for determining the resonance frequencies has traditionally been used to investigate the mechanical integrity of concrete cores, to assess the conformity of concrete constituents in different accelerated durability tests, and to ascertain constitutive properties such as the elastic modulus and the damping factor. This nondestructive technique has been quite appealed for evaluation of mechanical properties in all kinds of durability tests. The damage evolution is commonly assessed from the reduction of dynamic modulus which is produced as a result of any cracking process. However, the mechanical behavior of concrete is intrinsically nonlinear and hysteretic. As a result of a hysteretic stress-strain behavior, the elastic modulus is a function of the strain. In dynamic tests, the nonlinearity of the material is manifested by a decrease of the resonance frequencies, which is inversely proportional to the excitation amplitude. This phenomenon is commonly referred as fast dynamic effect. Once the dynamic excitation ceases, the material undergoes a relaxation process whereby the elastic modulus is restored to that at rest. This phenomenon is termed as slow dynamics. These phenomena (fast and slow dynamics) find their origin in the internal friction of the material. Therefore, in cement-based materials, the presence of microcracks and interfaces between its constituents plays an important role in the material nonlinearity. In the context of the assessment of concrete durability, the damage evolution is based on the increase of hysteresis, as a result of any cracking process. In this thesis three different nondestructive techniques are investigated, which use impacts for exciting the resonant frequencies. The first technique consists in determining the resonance frequencies over a range of impact forces. The technique is termed Nonlinear Impact Resonant Acoustic Spectroscopy (NIRAS). It consists in ascertaining the downward resonant frequency shift that the material undergoes upon increasing excitation amplitude. The second technique consists in investigating the nonlinear behavior by analyzing the signal corresponding to a single impact. This is, to determine the instantaneous frequency, amplitude and attenuation variations corresponding to a single impact event. This technique is termed as Nonlinear Resonant Acoustic Single Impact Spectroscopy (NSIRAS). Two techniques are proposed to extract the nonlinear behavior by analyzing the instantaneous frequency variations and attenuation over the signal ring down. The first technique consists in discretizing the frequency variation with time through a Short-Time Fourier Transform (STFT) based analysis. The second technique consists of a least-squares fit of the vibration signals to a model that considers the frequency and attenuation variations over time. The third technique used in this thesis can be used for on-site evaluation of structures. The technique is based on the Dynamic Acousto- Elastic Test (DAET). The variations of elastic modulus as derived through NIRAS and NSIRAS techniques provide an average behavior and do not allow derivation of the elastic modulus variations over one vibration cycle. Currently, DAET technique is the only one capable to investigate the entire range of nonlinear phenomena in the material. Moreover, unlike other DAET approaches, this study uses a continuous wave source as probe. The use of a continuous wave allows investigation of the relative variations of the elastic modulus, as produced by an impact. Moreover, the experimental configuration allows one-sided inspection.[ES] El ensayo de determinación de las frecuencias de resonancia ha sido tradicionalmente empleado para determinar la integridad mecánica de testigos de hormigón, en la evaluación de la conformidad de mezclas de hormigón en diversos ensayos de durabilidad, y en la terminación de propiedades constitutivas como son el módulo elástico y el factor de amortiguamiento. Esta técnica no destructiva ha sido ampliamente apelada para la evaluación de las propiedades mecánicas en todo tipo de ensayos de durabilidad. La evolución del daño es comúnmente evaluada a partir de la reducción del módulo dinámico, producido como resultado de cualquier proceso de fisuración. Sin embargo, el comportamiento mecánico del hormigón es intrínsecamente no lineal y presenta histéresis. Como resultado de un comportamiento tensión-deformación con histéresis, el módulo elástico depende de la deformación. En ensayos dinámicos, la no linealidad del material se manifiesta por una disminución de las frecuencias de resonancia, la cual es inversamente proporcional a la amplitud de excitación. Este fenómeno es normalmente denominado como dinámica rápida. Una vez la excitación cesa, el material experimenta un proceso de relajación por el cual, el módulo elástico es restaurado a aquel en situación de reposo. Este fenómeno es denominado como dinámica lenta. Estos fenómenos ¿dinámicas rápida y lenta¿ encuentran su origen en la fricción interna del material. Por tanto, en materiales basados en cemento, la presencia de microfisuras y las interfaces entre sus constituyentes juegan un rol importante en la no linealidad mecánica del material. En el contexto de evaluación de la durabilidad del hormigón, la evolución del daño está basada en el incremento de histéresis, como resultado de cualquier proceso de fisuración. En esta tesis se investigan tres técnicas diferentes las cuales utilizan el impacto como medio de excitación de las frecuencias de resonancia. La primera técnica consiste en determinar las frecuencias de resonancia a diferentes energías de impacto. La técnica es denominada en inglés: Nonlinear Impact Resonant Acoustic Spectroscopy (NIRAS). Ésta consiste en relacionar el detrimento que el material experimenta en sus frecuencias de resonancia, con el aumento de la amplitud de la excitación. La segunda técnica consiste en investigar el comportamiento no lineal mediante el análisis de la señal correspondiente a un solo impacto. Ésta consiste en determinar las propiedades instantáneas de frecuencia, atenuación y amplitud. Esta técnica se denomina, en inglés, Nonlinear Single Impact Resonant Acoustic Spectroscopy (NSIRAS). Se proponen dos técnicas de extracción del comportamiento no lineal mediante el análisis de las variaciones instantáneas de frecuencia y atenuación. La primera técnica consiste en la discretización de la variación de la frecuencia con el tiempo, mediante un análisis basado en Short-Time Fourier Transform (STFT). La segunda técnica consiste en un ajuste por mínimos cuadrados de las señales de vibración a un modelo que considera las variaciones de frecuencia y atenuación con el tiempo. La tercera técnica empleada en esta tesis puede ser empleada para la evaluación de estructuras in situ. La técnica se trata de un ensayo acusto-elástico en régimen dinámico. En inglés Dynamic Acousto-Elastic Test (DAET). Las variaciones del módulo elástico obtenidas mediante los métodos NIRAS y NSIRAS proporcionan un comportamiento promedio y no permiten derivar las variaciones del módulo elástico en un solo ciclo de vibración. Actualmente, la técnica DAET es la única que permite investigar todo el rango de fenómenos no lineales en el material. Por otra parte, a diferencia de otras técnicas DAET, en este estudio se emplea como contraste una onda continua. El uso de una onda continua permite investigar las variaciones relativas del módulo elástico, para una señal transito
[CAT] L'assaig de determinació de les freqüències de ressonància ha sigut tradicionalment empleat per a determinar la integritat mecànica de testimonis de formigó, en l'avaluació de la conformitat de mescles de formigó en diversos assajos de durabilitat, i en la terminació de propietats constitutives com són el mòdul elàstic i el factor d'amortiment. Esta tècnica no destructiva ha sigut àmpliament apel·lada per a l'avaluació de les propietats mecàniques en tot tipus d'assajos de durabilitat. L'evolució del dany és comunament avaluada a partir de la reducció del mòdul dinàmic, produït com resultat de qualsevol procés de fisuración. No obstant això, el comportament mecànic del formigó és intrínsecament no lineal i presenta histèresi. Com resultat d'un comportament tensió-deformació amb histèresi, el mòdul elàstic depén de la deformació. En assajos dinàmics, la no linealitat del material es manifesta per una disminució de les freqüències de ressonància, la qual és inversament proporcional a l'amplitud d'excitació. Este fenomen és normalment denominat com a dinàmica ràpida. Una vegada l'excitació cessa, el material experimenta un procés de relaxació pel qual, el mòdul elàstic és restaurat a aquell en situació de repòs. Este fenomen és denominat com a dinàmica lenta. Estos fenòmens --dinámicas ràpida i lenta troben el seu origen en la fricció interna del material. Per tant, en materials basats en ciment, la presència de microfissures i les interfícies entre els seus constituents juguen un rol important en la no linealitat mecànica del material. En el context d'avaluació de la durabilitat del formigó, l'evolució del dany està basada en l'increment d'histèresi, com resultat de qualsevol procés de fisuración. En esta tesi s'investiguen tres tècniques diferents les quals utilitzen l'impacte com a mitjà d'excitació de les freqüències de ressonància. La primera tècnica consistix a determinar les freqüències de ressonància a diferents energies d'impacte. La tècnica és denominada en anglés: Nonlinear Impact Resonant Acoustic Spectroscopy (NIRAS). Esta consistix a relacionar el detriment que el material experimenta en les seues freqüències de ressonància, amb l'augment de l'amplitud de l'excitació. La segona tècnica consistix a investigar el comportament no lineal per mitjà de l'anàlisi del senyal corresponent a un sol impacte. Esta consistix a determinar les propietats instantànies de freqüència, atenuació i amplitud. Esta tècnica es denomina, en anglés, Nonlinear Single Impact Resonant Acoustic Spectroscopy (NSIRAS). Es proposen dos tècniques d'extracció del comportament no lineal per mitjà de l'anàlisi de les variacions instantànies de freqüència i atenuació. La primera tècnica consistix en la discretización de la variació de la freqüència amb el temps, per mitjà d'una anàlisi basat en Short-Time Fourier Transform (STFT). La segona tècnica consistix en un ajust per mínims quadrats dels senyals de vibració a un model que considera les variacions de freqüència i atenuació amb el temps. La tercera tècnica empleada en esta tesi pot ser empleada per a l'avaluació d'estructures in situ. La tècnica es tracta d'un assaig acusto-elástico en règim dinàmic. En anglés Dynamic Acousto-Elastic Test (DAET). Les variacions del mòdul elàstic obtingudes per mitjà dels mètodes NIRAS i NSIRAS proporcionen un comportament mitjà i no permeten derivar les variacions del mòdul elàstic en un sol cicle de vibració. Actualment, la tècnica DAET és l'única que permet investigar tot el rang de fenòmens no lineals en el material. D'altra banda, a diferència d'altres tècniques DAET, en este estudi s'empra com contrast una ona contínua. L'ús d'una ona contínua permet investigar les variacions relatives del mòdul elàstic, per a un senyal transitori. A més, permet la inspecció d'elements per mitjà de l'accés per una sola cara.
Eiras Fernández, JN. (2016). Studies on nonlinear mechanical wave behavior to characterize cement based materials and its durability [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/71439
TESIS
Premiado
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Estoup, Jean-Marie. "Etude de la carbonatation endogene du beton et de ses applications a l'industrie du beton manufacture." Paris 6, 1987. http://www.theses.fr/1987PA066362.
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Etude bibliographique et experimentale de l'hydratation et de la carbonation du beton en dispersant dans la masse des polyisocyanates (hmdi ou mdi, qui accelerent l'hydratation, et ipdi, qui la retardent). Analyse des reactions. Resultats prometteurs de l'application de la technique pour ameliorer la stabilite de la teinte des betons colores, les resistances mecaniques a court terme, la tenue aux agents agressifs et la durabilite des fibres de verre dans une matrice de ciment
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Schmidt, Marek Wojciech, and Marek Schmidt@rl ac uk. "Phase formation and structural transformation of strontium ferrite SrFeOx." The Australian National University. Research School of Physical Sciences and Engineering, 2001. http://thesis.anu.edu.au./public/adt-ANU20020708.190055.
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Non-stoichiometric strontium iron oxide is described by an abbreviated formula SrFeOx (2.5 ≤ x ≤ 3.0) exhibits a variety of interesting physical and chemical properties over a broad range of temperatures and in different
gaseous environments. The oxide contains a mixture of iron in the trivalent and the rare tetravalent state. The material at elevated temperature is a mixed oxygen conductor and it, or its derivatives,can have practical
applications in oxygen conducting devices such as pressure driven oxygen
generators, partial oxidation reactors in electrodes for solid oxide fuel cells
(SOFC).
¶
This thesis examines the behaviour of the material at ambient and elevated temperatures using a broad spectrum of solid state experimental
techniques such as: x-ray and neutron powder diffraction,thermogravimetric and calorimetric methods,scanning electron microscopy and Mossbauer
spectroscopy. Changes in the oxide were induced using conventional thermal
treatment in various atmospheres as well as mechanical energy (ball milling).
The first experimental chapter examines the formation of the ferrite from
a mixture of reactants.It describes the chemical reactions and phase transitions that lead to the formation of the oxide. Ball milling of the reactants prior to annealing was found to eliminate transient phases from the reaction route and to increase the kinetics of
the reaction at lower temperatures.
Examination of the thermodynamics of iron oxide (hematite) used for the
reactions led to a new route of synthesis of the ferrite frommagnetite and
strontium carbonate.This chapter also explores the possibility of synthesis
of the material at room temperature using ball milling.
¶
The ferrite strongly interacts with the gas phase so its behaviour was studied under different pressures of oxygen and in carbon dioxide.The changes in ferrite composition have an equilibrium character and depend on temperature and oxygen concentration in the
atmosphere. Variations of the oxygen
content x were described as a function of temperature and oxygen partial
pressure, the results were used to plot an equilibrium composition diagram.
The heat of oxidation was also measured as a function of temperature and oxygen partial pressure.
¶
Interaction of the ferrite with carbon dioxide below a critical temperature
causes decomposition of the material to strontium carbonate and SrFe12O19 .
The critical temperature depends on the partial pressure of CO2 and above
the critical temperature the carbonate and SrFe12O19 are converted back into
the ferrite.The resulting SrFe12O19 is very resistant towards carbonation and
the thermal carbonation reaction does not lead to a complete decomposition
of SrFeOx to hematite and strontium carbonate.
¶
The thermally induced oxidation and carbonation reactions cease at room
temperature due to sluggish kinetics however,they can be carried out at ambient temperature using ball milling.The reaction routes for these processes are different from the thermal routes.The mechanical oxidation induces two
or more concurrent reactions which lead to samples containing two or more
phases. The mechanical carbonation on the other hand produces an unknown
metastable iron carbonate and leads a complete decomposition of the ferrite
to strontiumcarbonate and hematite.
¶
Thermally and mechanically oxidized samples were studied using Mossbauer
spectroscopy. The author proposes a new interpretation of the Sr4Fe4O11
(x=2.75) and Sr8Fe8O23 (x=2.875)spectra.The interpretation is based
on the chemistry of the compounds and provides a simpler explanation of
the observed absorption lines.The Mossbauer results froma range of compositions
revealed the roomtemperature phase behaviour of the ferrite also
examined using x-ray diffraction.
¶
The high-temperature crystal structure of the ferrite was examined using
neutron powder diffraction.The measurements were done at temperatures
up to 1273K in argon and air atmospheres.The former atmosphere protects
Sr2Fe2O5 (x=2.5) against oxidation and the measurements in air allowed
variation of the composition of the oxide in the range 2.56 ≤ x ≤ 2.81.
Sr2Fe2O5 is an antiferromagnet and undergoes phase transitions to the paramagnetic
state at 692K and from the orthorhombic to the cubic structure
around 1140K.The oxidized formof the ferrite also undergoes a transition
to the high-temperature cubic form.The author proposes a new structural
model for the cubic phase based on a unit cell with the Fm3c symmetry.
The new model allows a description of the high-temperature cubic form of
the ferrite as a solid solution of the composition end members.The results
were used to draw a phase diagramfor the SrFeOx system.
¶
The last chapter summarizes the findings and suggests directions for further research.
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Yerramshetty, Janardhan Srinivas. "The Effect of Compositional and Physicochemical Heterogeneity on Age-Related Fragility of Human Cortical Bone." Connect to Online Resource-OhioLINK, 2006. http://www.ohiolink.edu/etd/view.cgi?acc_num=toledo1166237815.
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Ribeiro, Gabriel Deltrejo. "Estudo do carbonato de cálcio tratado com agente de acoplamento Chartwell na substituição parcial de sílica em compósitos de borracha natural /." Bauru, 2020. http://hdl.handle.net/11449/192221.
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Orientador: Renivaldo José dos SantosResumo: Durante o processo de fabricação dos artefatos de borracha natural (BN), é possível adicionar cargas, podendo ser combinadas em função das propriedades finais pretendidas. Nesse sentido o carbonato de cálcio vem sendo utilizado como carga de enchimento nas formulações com borracha natural, apenas para aumentar o volume da amostra para a mesma quantidade de borracha implementada, buscando apenas a redução do custo final. Devido a demanda industrial, surge a necessidade de investigar a possibilidade de fazer com que uma carga, ora antes utilizada como enchimento, passe a atuar como carga de reforço mecânico, ou seja, a realização de tratamentos superficiais se torna uma possibilidade viável, para que a carga consiga realizar ligações cruzadas entre as cadeias de carbono da BN. Dessa forma, foi proposto neste trabalho o estudo de compósitos de borracha natural tipo crepe claro com carbonato de cálcio ultrafino tratado com 2% do Chartwell C-515.71HR^® para substituição parcial da sílica comercial tratada com silano, buscando identificar a influência deste agente de acoplamento no processo de vulcanização, a fim de melhorar a interação entre a borracha natural e carbonato de cálcio ultrafino. O preparo ocorreu em um misturador aberto de cilindros com a variação de 10 em 10 phr para as cargas, nos híbridos, iniciou-se em 40/00 até 00/40 (sílica/carbonato de cálcio ultrafino), e foi produzida uma amostra controle, com a mesma formulação, porém sem carga, denominada goma pura. Foi po... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: During the manufacturing process of natural rubber (BN) artifacts, it is possible to add loads, which can be combined depending on the desired final properties. In this sense, calcium carbonate has been used as filler in formulations with natural rubber, just to increase the sample volume for the same amount of rubber implemented, seeking only to reduce the final cost. Due to industrial demand, there is a need to investigate the possibility of causing a load, previously used as a filler, to act as a mechanical reinforcement load, that is, the performance of surface treatments becomes a viable possibility, so that the cargo is able to cross-link the BN carbon chains. Thus, the main objective of this work is the study of natural rubber composites of light crepe type with ultrafine calcium carbonate treated with 2% of Chartwell C-515.71HR^® for partial replacement of commercial silica treated with silane, seeking to identify the influence of this coupling agent in the vulcanization process, in order to improve the interaction between natural rubber and ultrafine calcium carbonate. The preparation took place in an open cylinder mixer with a variation of 10 in 10 phr for the loads, in the hybrids, it started in 40/00 until 00/40 (silica / ultrafine calcium carbonate), and a control sample was produced , with the same formulation, but without load, called pure gum. It was possible to replace up to 75% of the silica with treated calcium carbonate, but the best response was to replac... (Complete abstract click electronic access below)
Mestre
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Všetečka, Jan. "Stavebně technologický projekt revitalizace těžní věže Brno." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227274.
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The task of this diploma’s thesis was processing construction-technology project to revitalization the mining towers because of its current worsened state and subsequent adjustments for cultural activities.
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ANDRADE, Roberto Alvares de. "Efeito da ação de carbonatos sobre a expansão por umidade associada às propriedades cerâmicas de blocos destinados à construção civil." Universidade Federal de Campina Grande, 2009. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/2019.
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ROBERTO ALVARES DE ANDRADE - TESE PPGEP 2009..pdf: 16622579 bytes, checksum: 3d27a2976f134c663977125e77248ac7 (MD5)Made available in DSpace on 2018-10-18T18:45:52Z (GMT). No. of bitstreams: 1 ROBERTO ALVARES DE ANDRADE - TESE PPGEP 2009..pdf: 16622579 bytes, checksum: 3d27a2976f134c663977125e77248ac7 (MD5) Previous issue date: 2009-05-28
A partir dos últimos trinta anos, a difusão da alvenaria estrutural com o emprego de blocos cerâmicos passou a exigir destes últimos a capacidade de absorver esforços mecânicos provenientes do peso próprio das edificações e das sobrecargas a elas transmitidas. As pesquisas para a viabilização desta nova função dos blocos cerâmicos não foram, até o presente momento, tão intensas a ponto de garantirem de forma efetiva o seu bom desempenho estrutural, e alguns problemas relacionados com as suas propriedades mecânicas e expansão por umidade (EPU) passaram a evidenciar a necessidade do aprimoramento das suas características. Foi com tal propósito que nesta tese se desenvolveram algumas investigações voltadas à detecção de novos parâmetros que aumentassem o acervo de conhecimento da EPU e das propriedades mecânicas dos blocos cerâmicos e, em tal direcionamento, partiu-se de informações da literatura técnica relativas ao efeito benéfico dos óxidos de cálcio e de magnésio incorporados às massas tomadas como matérias-primas dos blocos cerâmicos. Os resultados obtidos com corpos-de-prova autoclavados permitiram o confronto das suas características atuais com aquelas projetadas para o término da sua vida útil. Estudos para constatar eventuais minimizações da EPU e controle da resistência mecânica de corpos cerâmicos de vedação foram desenvolvidos com o emprego das massas das Cerâmicas ditas "A" e "B", as quais foram manipuladas de forma idêntica. Os teores diferenciados da incorporação feita a cada uma das citadas massas dos carbonatos empregados, a saber, os carbonatos de cálcio e de magnésio, foram calculados com o propósito de gerarem idênticos teores de óxidos após o desprendimento do dióxido de carbono ao longo do ciclo da queima. Os resultados obtidos evidenciaram, para os blocos obtidos ao longo de ciclo de queima entre 850-1000°C, uma redução universal da EPU decorrente da ação do carbonato de cálcio, e uma discreta tendência da sua redução decorrente da adição do carbonato de magnésio; tais reduções de EPU se deveram à formação de fases cristalinas desencadeadas pela ação dos referidos carbonatos. O maior valor de perda de massa, o surgimento da brucita, e os elevados valores de absorção de água decorrentes das adições magnesianas justificaram as menores reduções, ou ausência de reduções, de EPUs delas decorrentes. Quando as duas citadas massas foram manipuladas sem adições, aquela com maior teor de argila apresentou valores mais elevados de EPU, o que se explica, já que a maior quantidade de argila forma maior quantidade de fase vítrea. As adições utilizadas intervieram não só na EPU como também nas propriedades cerâmicas dos corpos-de-prova analisados. As adições calcárias e magnesianas, de forma quase absoluta, tenderem ao aumento das absorções de água, e, quanto à interferência no aumento da resistência mecânica, marcante foi a grande suscetibilidade ao teor "médio" (16,3%) de adição magnesiana associado à temperatura de queima de 1000°C, situação em que a tensão de ruptura à flexão, tanto para a Cerâmica "A" quanto para a Cerâmica "B", apresentou valores desproporcionalmente superiores àqueles relativos a temperaturas de queima inferiores a 1000°C, fato provavelmente devido à efetiva presença da enstatita e da ringwoodita a esta temperatura de queima.
The use of ceramic blocks in structural masonry since the last thirty years has demanded their capacity of absorbing mechanic efforts resulting from the own weight of building and respective overloads. Researches intended to make possible the new performance of ceramic blocks have not been intensive enough to definitively assure a good structural performance, and some problems concerning their mechanic properties and moisture expansion have shown the need of deeply improve their characteristics. Aiming at that purpose, this doctoral thesis has developed some investigations to identify new patterns that may contribute to increase the knowledge of moisture expansion and mechanic properties of ceramic blocks. To achieve that purpose, we started from information provided by technical literature concerning the good effects of calcium oxide and magnesium oxide incorporated to the rawmaterials of ceramic blocks. Results obtained from the autoclaved specimens have shown the differences between their present characteristics and those expected to be at the end of their working life. Researches to confirm possible moisture expansion minimizations and control of mechanic resistance of packing ceramic bodies have been carried out by using ceramic masses called "A" and "B", handled alike. Different contents of the carbonate used, such as calcium and magnesium carbonates, have been estimated, with the purpose of providing the same oxide contents after the carbon dioxide exit, along the firing cycle. Blocks obtained during a firing cycle between 850-1000°C show a universal moisture expansion decrease resulting from the action of calcium carbonate and a strong trend of its decrease resulting from the addition of magnesium carbonate. Such moisture expansion decreases resulted from the crystalline stages developed by the activity of those carbonates. The highest rate of mass loss, ocurrence of brucite and high rates of water absorption resulting from the addition of magnesium carbonate justify shorter decreases or even non-reduction or moisture expansion resulting therefrom. When both masses were handled without additions, the one with higher rate of clay showed higher moisture expansion values, since a higher rate of clay responsible for higher quantity of vitreous phases. Added material interfered both in moisture expansion and in the ceramic properties of observed specimens. Remarkable was the high susceptibility of the medium content (16.3%) of magnesium carbonate addition interfering in the increase of mechanical resistance, joined to the firing temperature at 1000°C, and acording to this tendency, rupture tension, in both Ceramics "A" and "B", showed disproportionably higher figures relative to firing temperatures under 1000°C. This fact is probably due to the effective presence of enstatite and ringwoodite at this firing temperature.
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Bartley, Bertilia Lauralee. "Argamassas de cimento portland aditivado com partículas de calcário mineral e partículas ultrafinas de carbonato de cálcio : morfologia, propriedades mecânicas e durabilidade." Universidade Federal de Sergipe, 2016. https://ri.ufs.br/handle/riufs/3529.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESThis study concentrates on the use of micro particles of limestone (CMV) and nano scale calcium carbonate (Np-CaCO3) in Portland cement (OPC) substitution in order to evaluate the influence in hydration reactions, microstructural morphology, mechanical properties and the durability of cement pastes and mortar. Specimens where characterized by X-ray diffraction, scanning electron microscopy, uniaxial compression, micro hardness and thermo gravimetric analysis. Atypical morphologies of calcium silicate hydrate (C-S-H) were observed in the pastes in the presence of high amount of Np-CaCO3. The results indicate that the Np-CaCO3 is reactive; accelerating early age C-S-H formation. Based on the morphological and mechanical properties, a synergetic effect was observed by the combined addition of CMV with low amounts of Np-CaCO3. Compressive strength results of the mortars are compatible with the standard requisite of the American Society of Testing Materials (ASTM). The durability of the mortars was evaluated by expositional aging methods in natural and laboratory environment for 6 months. The mechanical properties and durability of the composite cement mortars are competitive with results obtained by the reference mortars. By overall analysis of the results, it was concluded that OPC substitution of 10-30 wt.% CMV, when combined with controlled amount of Np-CaCO3 prove viable.
A presente pesquisa se concentra no uso de calcário mineral micrométrico (CMV) e nanopartículas de carbonato de cálcio (Np-CaCO3) na substituição de cimento Portland (OPC), visando avaliar a influência nas reações de hidratação, morfologia, microestrutura, propriedades mecânicas e durabilidade de pastas e argamassas de cimento. Os corpos de prova foram caracterizados por difração de raios X, microscopia eletrônica de varredura, ensaios de compressão, microdureza e análise termogravimétrica. Nas pastas foram observadas morfologias atípicas de silicato de cálcio hidratado (C-S-H) na presença de altos teores de Np-CaCO3. Os resultados indicam que as Np-CaCO3 atuam como reativos acelerando a formação do C-S-H nas primeiras idades. Em base das propriedades morfológicas e mecânicas, foi observado um efeito sinérgico quando combinados baixos teores Np-CaCO3 com CMV. Os valores de resistência a compressão das argamassas são compatíveis com os valores padrão das normas da Sociedade Americana de Testes e Materiais (ASTM). As argamassas envelhecidas em ambiente natural e laboratório por até 6 meses de exposição mostraram propriedades mecânicas e durabilidade comparáveis com resultados obtidos para argamassas feitas com cimentos de referência. Foi viável a substituição de OPC, mesmo para altos teores de carbonatos (10-35%), em especial quando combinados com teores controlados de Np-CaCO3.
Books on the topic "Mechanical carbonation"
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Häkkinen, Tarja. Influence of high slag content on the basis mechanical properties and carbonation of concrete. Espoo, Finland: Technical Research Centre of Finland, 1993.
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Leonovich, Sergey, Evgeniy Shalyy, Elena Polonina, Elena Sadovskaya, Lev Kim, and 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.
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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.
Book chapters on the topic "Mechanical carbonation"
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Fabbri, A., J. Corvisier, A. Schubnel, F. Brunet, J. Fortin, B. Goffé, V. Barlet-Gouédard, G. Rimmelé, and Y. Leroy. "Effect of Carbonation on the Hydro-Mechanical Properties of Portland Cement." In Thermo-Hydromechanical and Chemical Coupling in Geomaterials and Applications, 613–20. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118623565.ch64.
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Ran, Jin, Qi Feng, Jinxi Zhang, Lin Wang, and Honglin Cao. "Mechanical Properties of Concrete Under the Alternate Carbonation and Freezing–Thawing Actions." In Lecture Notes in Electrical Engineering, 109–19. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-5429-9_8.
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Castellini, Marta, Oana Adriana Cuzman, Silvia Rescic, Marco Tanganelli, Stefano Landi, and Cristiano Riminesi. "Conservation Strategies for the Palazzo degli Affari in Florence (Italy): The Role of Protective Treatments on the Concrete Carbonation Resistance." In Lecture Notes in Mechanical Engineering, 344–58. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-17594-7_26.
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Gaur, Tarun, Lav Singh, and Shashank Bishnoi. "Influence of Carbonation on Mechanical and Transport Properties of Limestone Calcined Clay Blend Mortar Mix." In RILEM Bookseries, 621–29. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-2806-4_69.
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Liu, Zhiyuan, Philip Van den Heede, and Nele De Belie. "The Effect of Mechanical Load on Carbonation of Concrete: Discussion on Test Methods and Results." In RILEM Bookseries, 401–10. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-76551-4_36.
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Dang, Quoc Viet, Aoi Okada, Yuko Ogawa, and 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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Mbugua, R., R. Salim, and 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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Lee, Sang Hyun, Han Seung Lee, and Ki Bong Park. "Study on an FEM Analysis to Evaluate Restrain-Performance of Surface-Finishes for Carbonation." In Advances in Fracture and Damage Mechanics VI, 477–80. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-448-0.477.
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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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Rubin, James B., and Craig M. V. Taylor. "Enhancing the Properties of Portland Cements Using Supercritical Carbon Dioxide." In Green Chemistry Using Liquid and Supercritical Carbon Dioxide. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780195154832.003.0021.
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Supercritical CO2 (sc CO2) is being used to accelerate the natural aging reactions (i.e., carbonation) of Portland cement. This treatment method alters the bulk properties of cement, producing profound changes in both structure and chemical composition. As a result of these changes, the mechanical and transport properties of these cements are also dramatically affected, and they display reduced porosity, permeability and pH, as well as increased density and compressive strength. Two areas of application for the sc CO2 treatment of portland cement have been undergoing investigation. Because the calcium carbonate (CaCO3) formed during the accelerated carbonation reaction is found to have excellent cementing properties, it is possible to replace a large fraction of the relatively expensive Portland cement with industrial waste products, such as fly ash and kiln dusts, which have inherently inferior cementing properties. These modified Portland cements, incorporating significant volume fractions of industrial wastes, can be used as low-cost building materials. The second area of application deals with the enhancement of Portland cements used to encapsulate waste products. Portland cement is used as an immobilization matrix for low- and intermediate-level radioactive waste by both the U.S. federal government (Huang et al., 1994) and civilian nuclear power companies in the United States (Wilk, 1997) and abroad (Wilding, 1992). Transportation issues relating to water content, radiolysis, and radionuclide content often preclude the ultimate disposal of these cemented wasteforms (U.S. DOE, 1996). However, the structural and chemical changes produced by accelerated carbonation have been shown to address these problems satisfactorily (Hartmann et al., 1999).
Conference papers on the topic "Mechanical carbonation"
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Zheng, Y. H., and R. S. Amano. "Experimental and Numerical Modeling of Gaseous Carbon Dioxide Injecting Into Aqueous Water in Bottle Filler System." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/htd-24174.
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Abstract An efficient enhancement of the carbonation rate in the bottle filling stage can substantially increase the production in beverage industries. The bottle filling system currently used in most of the manufacturers can still be improved for a better performance of carbonation by designing the injection tube system. This paper reports on an experimental and numerical mass transfer modeling that can simulate the dissolution process of gaseous carbon dioxide into aqueous water in the bottle filler system. In order to establish the operating characteristics of the bottle filler system, an ordinary tap water and pure carbon dioxide were used as the liquid-gas system. The two-phase numerical modeling was developed that can serve as a framework for the continuous improvement of the design of the carbonation process in the bottle filler system. For an optimal design of CO2 injection tube and flow conditions, a computational fluid dynamics (CFD) approach is one of the most power tools. However, since only limited experimental data are available in the open literature to verify the computational results, an experiment study was performed to obtain measurements of CO2 level, temperature, and pressure during the carbonation process in the bottle filled with liquid. Both experimental and numerical studies of various flow condition and different sizes of injection tube are presented in this paper.
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ARCE, G.L.A.F., NETO, T.G.S., Perrella, J.A.B., Carvalho Jr., J.A., and LUNA, C.M.R. "EXERGETIC AND ENVIRONMENTAL ASSESSMENT OF MINERAL CARBONATION PROCESSES IN BRAZIL." In 23rd ABCM International Congress of Mechanical Engineering. Rio de Janeiro, Brazil: ABCM Brazilian Society of Mechanical Sciences and Engineering, 2015. http://dx.doi.org/10.20906/cps/cob-2015-1499.
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Kenarsari, Saeed Danaei, and Yuan Zheng. "CO2 Capture Using Calcium Oxide Applicable to In-Situ Separation of CO2 From H2 Production Processes." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62619.
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A lab-scale CO2 capture system is designed, fabricated, and tested for performing CO2 capture via carbonation of very fine calcium oxide (CaO) with particle size in micrometers. This system includes a fixed-bed reactor made of stainless steel (12.7 mm in diameter and 76.2 mm long) packed with calcium oxide particles dispersed in sand particles; heated and maintained at a certain temperature (500–550°C) during each experiment. The pressure along the reactor can be kept constant using a back pressure regulator. The conditions of the tests are relevant to separation of CO2 from combustion/gasification flue gases and in-situ CO2 capture process. The inlet flow, 1% CO2 and 99% N2, goes through the reactor at the flow rate of 150 mL/min (at standard conditions). The CO2 percentage of the outlet gas is monitored and recorded by a portable CO2 analyzer. Using the outlet composition, the conversion of calcium oxide is figured and employed to develop the kinetics model. The results indicate that the rates of carbonation reactions considerably increase with raising the temperature from 500°C to 550°C. The conversion rates of CaO-carbonation are well fitted to a shrinking core model which combines chemical reaction controlled and diffusion controlled models.
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Kely Regina Maximo Vieira, Gretta Larisa Aurora Arce Ferrufino, Ivonete Ávila, Vitor Oliveira Facio, João Andrade de Carvalho Jr., and Turibio Gomes Soares Neto. "ACID DISSOLUTION STUDIES OF BRAZILIAN SERPENTINITE ROCKS APPLIED TO MINERAL CARBONATION PROCESSES." In 23rd ABCM International Congress of Mechanical Engineering. Rio de Janeiro, Brazil: ABCM Brazilian Society of Mechanical Sciences and Engineering, 2015. http://dx.doi.org/10.20906/cps/cob-2015-1112.
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Manfredi Gasparovic, Claudia Luiza, George Stanescu, and Marcelo Risso Errera. "FIRST-ORDER CONSTRUCT OF A MINERAL CARBONATION SYSTEM FOR POST-COMBUSTION CARBON CAPTURE." In 26th International Congress of Mechanical Engineering. ABCM, 2021. http://dx.doi.org/10.26678/abcm.cobem2021.cob2021-2004.
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Escosa, Jesu´s M., Cristo´bal Cortes, and Luis M. Romeo. "Repowering of Fossil Fuel Power Plants and Reversible Carbonation/Calcination Cycle for CO2 Abatement." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-79883.
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Fossil fuel power plants account for about a third of global carbon dioxide emissions. Coal is the major power-generation fuel, being used twice as extensively as natural gas (IEA, 2003). Moreover, on a global scale, coal demand is expected to double over the period to 2030; IEA estimates that 4500 GWe of new installed power will be required. Coal is expected to provide 40% of this figure. It is thus obvious that coal power plants must be operative to provide such amount of energy in the short term, at the same time reducing their CO2 emissions in a feasible manner and increasing their efficiency and capacity. However, the main technologies currently considered to effect CO2 capture, both post-and pre-combustion, introduce a great economic penalty and largely reduce the capacity and efficiency. One of these technologies involves the separation of CO2 from high temperature flue gases using the reversible carbonation reaction of CaO and the calcination of CaCO3. The process is able to simultaneously capture sulfur dioxide. The major disadvantage of this well-known concept is the great amount of energy consumption in the calcinator and auxiliary equipment. This paper proposes a new, feasible approach to supply this energy which leads to an optimal integration of the process within a conventional coal power plant. Calcination is accomplished in a kiln fired by natural gas, whereas a gas turbine is used to supply all the auxiliary power. Flue gases from the kiln and the gas turbine can substitute a significant part of the heat duty of the steam cycle heaters, thus accomplishing feed water repowering of the steam turbine. This novel CO2-capture cycle is proposed to be integrated with aging coal-fired power plants. The paper shows that an optimal integration of both elements represents one of the best methods to simultaneously achieve: a) an increase of specific generating capacity in a very short period of time, b) a significant abatement of CO2 emissions, and c) an increase of plant efficiency in a cost-effective way.
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ARCE, G.L.A.F., AVILA, I., NETO, T.G.S., LUNA, C.M.R., CARVALHO Jr. J.A., VIEIRA, K.M., OLIVEIRA, V.F., and SANTOS, J.C. "A STUDY OF VARIABLES IN THE CHEMICAL ACTIVATION OF BRAZILIAN SERPENTINITE FOR CO2 MINERAL CARBONATION." In 23rd ABCM International Congress of Mechanical Engineering. Rio de Janeiro, Brazil: ABCM Brazilian Society of Mechanical Sciences and Engineering, 2015. http://dx.doi.org/10.20906/cps/cob-2015-1500.
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Martinez Molina, W., E. M. Alonso Guzman, H. L. Chavez Garcia, C. Lara Gomez, F. M. Gonzalez Valdez, T. Perez Lopez, J. Reyes Trujeque, et al. "Analysis of Carbonation in Mortars made with Solid Waste as a Substitute for Cement." In 2015 International Conference on Structural, Mechanical and Material Engineering. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/icsmme-15.2015.53.
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Li, Chu, Junkuo Li, and Shijie Gong. "Experimental study on carbonation resistance of ultra high performance concrete for electric pole." In 2nd International Conference on Mechanical, Electronics, and Electrical and Automation Control (METMS 2022), edited by Xuexia Ye. SPIE, 2022. http://dx.doi.org/10.1117/12.2634937.
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Hoyos, Catalina Gómez, and Analia Vazquez. "Carbon Dioxide Sequestration in Portland Cement Paste Modified With Cellulose Microcrystalline." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-11528.
Full textAbstract:
This work evaluated the dynamical mechanical properties of Portland cement paste modified with cellulose microcrystalline (MCC) before and after exposition to CO2 saturated environment during 4 h. All the cement paste samples were subjected to thermogravimetrical analysis (TGA) before and after carbonation process. Changes in morphology of the samples were studied in a field emission electron microscope (FE-SEM); additionally changes generated in hydration kinetic by the addition of MCC to cement paste, were followed by measuring the adiabatic temperature during the first 24 h of reaction. The addition of MCC delayed the hydration reaction. TGA results shown that cement past with MCC was carbonated. The carbonation process in TGA was evaluated by the increase in the size of the peak around 680 oC related with calcium carbonate thermal degradation. The dynamical mechanical analysis shown that, cement paste with MCC increased significantly its storage modulus after CO2 exposition.
Reports on the topic "Mechanical carbonation"
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M.J. McKelvy, J. Diefenbacher, R. Nunez, R.W. Carpenter, and A.V.G. Chizmeshya. SIMULTANEOUS MECHANICAL AND HEAT ACTIVATION: A NEW ROUTE TO ENHANCE SERPENTINE CARBONATION REACTIVITY AND LOWER CO2 MINERAL SEQUESTRATION PROCESS COST. Office of Scientific and Technical Information (OSTI), January 2005. http://dx.doi.org/10.2172/840464.
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