Journal articles on the topic 'Carbonation'
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1
Cho, Kyungil, Yeryeong Kang, Sukbyung Chae, and Changhyuk Kim. "Forced Mineral Carbonation of MgO Nanoparticles Synthesized by Aerosol Methods at Room Temperature." Nanomaterials 13, no. 2 (January 9, 2023): 281. http://dx.doi.org/10.3390/nano13020281.
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Magnesium oxide (MgO) has been investigated as a wet mineral carbonation adsorbent due to its relatively low adsorption and regeneration temperatures. The carbon dioxide (CO2) capture efficiency can be enhanced by applying external force on the MgO slurry during wet carbonation. In this study, two aerosol-processed MgO nanoparticles were tested with a commercial MgO one to investigate the external force effect on the wet carbonation performance at room temperature. The MgO nano-adsorbents were carbonated and sampled every 2 h up to 12 h through forced and non-forced wet carbonations. Hydrated magnesium carbonates (nesquehonite, artinite and hydromagnesite) were formed with magnesite through both wet carbonations. The analyzed results for the time-dependent chemical compositions and physical shapes of the carbonation products consistently showed the enhancement of wet carbonation by the external force, which was at least 4 h faster than the non-forced carbonation. In addition, the CO2 adsorption was enhanced by the forced carbonation, resulting in a higher amount of CO2 being adsorbed by MgO nanoparticles than the non-forced carbonation, unless the carbonation processes were completed. The adsorbed amount of CO2 was between the maximum theoretical amounts of CO2 adsorbed by nesquehonite and hydromagnesite.
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Abidoye, Luqman Kolawole, and Diganta B. Das. "Carbon Storage in Portland Cement Mortar: Influences of Hydration Stage, Carbonation Time and Aggregate Characteristics." Clean Technologies 3, no. 3 (July 30, 2021): 563–80. http://dx.doi.org/10.3390/cleantechnol3030034.
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This study elucidates the effects of the particle size, carbonation time, curing time and pressure on the efficiency of carbon storage in Portland cement mortar. Using pressure chamber experiments, our findings show how carbonation efficiency increases with a decrease in the particle size. Approximately 6.4% and 8.2% (w/w) carbonations were achieved in the coarse-sand and fine-sand based mortar samples, respectively. For the hydration/curing time of 7 h, up to 12% carbonation was achieved. This reduced to 8.2% at 40 h curing period. On the pressure effect, for comparable curing conditions, 2 bar at 7 h carbonation time gives 1.4% yield, and 8.2% at 5 bar. Furthermore, analysing the effect of the carbonation time, under comparable conditions, shows that 4 h of carbonation time gives up to 8.2% yield while 64 h of carbonation gives up to 18.5%. It can be reliably inferred that, under similar conditions, carbonation efficiency increases with lower-sized particles or higher-surface areas, increases with carbonation time and higher pressure but decreases with hydration/curing time. Microstructural analyses with X-ray diffraction (XRD) and scanning electron microscopy (SEM) further show the visual disappearance of calcium-silicate-hydrate (C-S-H) together with the inhibition of ettringite formation by the presence of CO2 and CaCO3 formation during carbonation.
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Wu, Hao Ze, Jun Chang, Zheng Zhao Pan, and Xin Cheng. "Effects of Carbonation on Steel Slag Products." Advanced Materials Research 177 (December 2010): 485–88. http://dx.doi.org/10.4028/www.scientific.net/amr.177.485.
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The effects of carbonation on structure and properties of steel slag specimens are evaluated by some different testing technologys in this paper. The experimental results of strength and soundness show that the compressive strength of samples is improved 6-8 times due to carbonation, and carbonated specimens have qualified autoclave soundness. Also the carbonation reactions of steel slag and the reason that why strength and soundness improved are analyzed by chemical titration, XRD, TG, SEM and MIP etc. Experimental results indicate that in steel slag specimens, f-CaO, f-MgO, partial C2S and C3S minerals could be carbonated, and 105～110 gram CO2 gas could be sequestrated after carbonating per kilogram of steel slag specimens.
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Kruk, Aleksei, and Alexander Sokol. "Role of Volatiles in the Evolution of a Carbonatitic Melt in Peridotitic Mantle: Experimental Constraints at 6.3 GPa and 1200–1450 °C." Minerals 12, no. 4 (April 11, 2022): 466. http://dx.doi.org/10.3390/min12040466.
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Reconstruction of the mechanisms of carbonatitic melt evolution is extremely important for understanding metasomatic processes at the base of the continental lithospheric mantle (CLM). We have studied the interaction between garnet lherzolite and a carbonatitic melt rich in molecular CO2 and H2O in experiments at 6.3 GPa and 1200–1450 °C. The interaction with garnet lherzolite and H2O-bearing carbonatite melt leads to wehrlitization of lherzolite, without its carbonation. Introduction of molecular CO2 and H2O initiates carbonation of olivine and clinopyroxene with the formation of orthopyroxene and magnesite. Partial carbonation leads to the formation of carbonate–silicate melts that are multiphase saturated with garnet harzburgite. Upon complete carbonation of olivine already at 1200 °C, melts with 27–31 wt% SiO2 and MgO/CaO ≈ 1 are formed. At 1350–1450 °C, the interaction leads to an increase in the melt fraction and the MgO/CaO ratio to 2–4 and a decrease in the SiO2 concentration. Thus, at conditions of a thermally undisturbed CLM base, molecular CO2 and H2O dissolved in metasomatic agents, due to local carbonation of peridotite, can provide the evolution of agent composition from carbonatitic to hydrous silicic, i.e., similar to the trends reconstructed for diamond-forming high density fluids (HDFs) and genetically related proto-kimberlite melts.
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Pelchat, Marcia L., Bruce Bryant, Rosario Cuomo, Francesco Di Salle, Ronnie Fass, and Paul Wise. "Carbonation." Nutrition Today 49, no. 6 (2014): 308–12. http://dx.doi.org/10.1097/nt.0000000000000010.
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Lee, Hyesung, Tae Wook Kim, Soung Hyoun Kim, Yu-Wei Lin, Chien-Tsung Li, YongMan Choi, and Changsik Choi. "Carbon Dioxide Capture and Product Characteristics Using Steel Slag in a Mineral Carbonation Plant." Processes 11, no. 6 (May 31, 2023): 1676. http://dx.doi.org/10.3390/pr11061676.
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Carbon capture and storage (CCS) technology can reduce CO2 emissions by 85 to 95% for power plants and kilns with high CO2 emissions. Among CCS technologies, carbon dioxide capture using steel slag is a method of carbonating minerals by combining oxidized metals in the slag, such as CaO, MgO, and SiO2, with CO2. This study assessed the amount of CO2 captured and the sequestration efficiency in operating a mineral carbonation plant with a CO2 capture capacity of 5 tons/day by treating the exhaust gas from a municipal waste incinerator and identified the characteristics of the mineral carbonation products. As a result, the average concentration of CO2 in the inflow and outflow gas during the reaction time was 10.0% and 1.1%, respectively, and the average CO2 sequestration efficiency was 89.7%. This resulted in a conversion rate of CaO of > 90%. This study manifested that mineral carbonation products are more stable than steel slag as a construction material and are effective at sequestering CO2 by forming chemically stable CaCO3.
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He, Haijie, Yuxuan Wang, Ji Yuan, Ke Xu, Shifang Wang, Hongxia Qiao, Tao Wu, et al. "A New Type of Mineral Admixture and Its Impact on the Carbonation Resistance of EPS Concrete." Sustainability 15, no. 9 (April 26, 2023): 7233. http://dx.doi.org/10.3390/su15097233.
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In this study, the effect of microbead dosages (0%, 5%, 10%, 15%, and 20%) on the carbonation resistance of expanded polystyrene (EPS) concrete was investigated. Five groups of EPS concrete specimens were produced and underwent rapid carbonation testing. The carbonation depth and strength after carbonation of the specimens were measured at different carbonation ages (7 days, 14 days, and 28 days) and analyzed to determine the effect of microbead dosages and compressive strength on carbonation resistance. Results indicated that the carbonation depth increased with the progression of carbonation time. The introduction of microbeads was found to significantly improve the carbonation resistance of EPS concrete, leading to a reduction in carbonation depth of over 50% after 28 days and an increase in strength after carbonation by 18–56%. A relative compressive strength model for EPS concrete after carbonation was developed, which could accurately characterize the growth of compressive strength. Based on the analysis of EPS concrete carbonation depth data, a prediction model for the carbonation depth of EPS concrete with microbead dosage was established through fitting, providing improved accuracy in predicting carbonation resistance. The microstructure of EPS concrete was also examined using scanning electron microscopy to uncover the underlying mechanisms of microbead enhancement on carbonation resistance. These findings have potential implications for future research and engineering applications in the carbonation resistance of EPS concrete.
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Guo, Qun, Lexin Jiang, Jianmin Wang, and Junzhe Liu. "Analysis of Carbonation Behavior of Cracked Concrete." Materials 15, no. 13 (June 27, 2022): 4518. http://dx.doi.org/10.3390/ma15134518.
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The crack and carbonation of concrete pose a great challenge to its durability. Therefore, this paper studies the effect of cracks on the carbonation depth of cement paste under different factors. The relationship between carbonation and cracks was determined, and the carbonation mechanism of cement paste with cracks was clarified. The results show that a small water–binder ratio can effectively inhibit the carbonation process. The bidirectional carbonation enlarged the carbonation area around the crack. Within 21 days of the carbonation, the carbonation depth increased with carbonation time, and the Ca(OH)2 on the surface of the specimen was sufficient, allowing for a convenient chemical reaction with CO2. The influence of crack width on the carbonation process at the crack was greater than the influence of the crack depth. Carbonation influenced the hydration of cement-based materials, altering the types and quantities of hydration products. In conclusion, accurately predicting the regularity of carbonation in cracked structures is critical for improving the durability of concrete.
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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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Cui, Dong, Xiaobao Zuo, Keren Zheng, and Sudip Talukdar. "Tomography-Based Investigation on the Carbonation Behavior through the Surface-Opening Cracks of Sliced Paste Specimen." Materials 13, no. 8 (April 11, 2020): 1804. http://dx.doi.org/10.3390/ma13081804.
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Understanding the cracking behavior during carbonation is of high importance, and the cracks can serve as a shortcut for CO2 diffusion, which can further accelerate the carbonation process itself. In this study, a sliced paste sample was taken for an accelerated carbonation test, and the cracking behavior, as well as its impact on carbonation, was investigated through a novel extended attenuation method based on X-ray (XRAM) which is performed primarily on computed tomography (CT). Surface-opening cracks at different carbonation ages were rendered, based on which a full view on the carbonation-cracking behavior was built. The results reveal that the crack paths can rapidly be occupied by CO2, and that leads to the generation of V-shaped carbonation cusps pervading the carbonation fronts. The V-shaped carbonation cusps were mostly generated at the early carbonation age (within 14 days), attesting to a less intact sample surface as compared to the inside area. Moreover, this study confirms that the carbonated area would split into two independent zones with variant carbonation degree due to the increased humidity level near the sample surface. The current work reveals the interconnection between carbonation and cracking, and the results can be used for the designing of cement-based materials with better carbonation and cracking resistance.
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Zha, Xiao Xiong, Hai Yang Wang, and Gan Lin Feng. "The Carbon Absorb of Cement-Based Material in the Accelerated Carbonation Test." Advanced Materials Research 905 (April 2014): 318–21. http://dx.doi.org/10.4028/www.scientific.net/amr.905.318.
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Carbonation is a common influence of cement-based material. And the accelerated carbonation is used in material property modify. With the reaction in the material when carbonating, the carbon dioxide will be solidifying in the material, in the shape of precipitation of calcium carbonate filled the pore. But the ability of the carbon absorbing is unknown, in this paper, some cement-based building materials are took in test, including the aerated brick, cement tile, concrete, and cement mortar. In according to the results, it has found that the carbon absorbing ability is different, and with the carbon absorbing, the strength also increasing. The aerated brick is greatest and the condition of temperature, pressure and reaction time is lowest, which give a reference on the way of the greenhouse gas transform and reduced.
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Zhao, Jun, Eskinder Desta Shumuye, Zike Wang, and Gashaw Assefa Bezabih. "Performance of GGBS Cement Concrete under Natural Carbonation and Accelerated Carbonation Exposure." Journal of Engineering 2021 (March 27, 2021): 1–16. http://dx.doi.org/10.1155/2021/6659768.
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One of the primary problems related to reinforced concrete structures is carbonation of concrete. In many cases, depth of carbonation on reinforced concrete structures is used to evaluate concrete service life. Factors that can substantially affect carbonation resistance of concrete are temperature, relative humidity, cement composition, concentration of external aggressive agents, quality of concrete, and depth of concrete cover. This paper investigates the effect of varying the proportions of blended Portland cement (ordinary Portland cement (OPC) and ground granulated blast-furnace slag (GGBS)) on mechanical and microstructural properties of concrete exposed to two different CO2 exposure conditions. Concrete cubes cast with OPC, and various percentages of GGBS (0%, 30%, 50%, and 70%) were subjected to natural (indoor) and accelerated carbonation exposure. The aim of this paper is to present the research findings and authenticate the literature results of carbonation by using GGBS cement in partial replacement of OPC. The concretes with OPC are compared to concretes with various percentages of GGBS, to assess the carbonation depth as well as rate of carbonation of GGBS-based concretes, under both accelerated carbonation and natural carbonation exposure conditions. Even though GGBS cement increases the carbonation depth, the results are not the same with different GGBS replacement percentages. A correlation is made between concrete samples exposed to 15 ± 2% carbon dioxide (CO2) concentration and those exposed to natural CO2 concentration. The results reveal that the products formed by carbonation are similar under both exposure conditions. The experimental tests also revealed that GGBS cement concrete has a lower carbonation resistance than OPC concrete, due to the consumption of portlandite by the pozzolanic reaction. The combination of 70% OPC and 30% GGBS behaved well enough with respect to accelerated carbonation exposure, the depth of carbonation being roughly equivalent to that of control group (100% OPC). The results also show that rate of carbonation becomes more sensitive as the percentage of GGBS replacement increases (binder ratio), rather than duration of curing. Concretes exposed to natural carbonation (indoor) achieved lower carbonation rates than those exposed to accelerated carbonation.
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Li, Jianzhi, Haiqun Yang, and Handong Wu. "Evaluation of Concrete Carbonation Based on a Fiber Bragg Grating Sensor." Micromachines 15, no. 1 (December 22, 2023): 29. http://dx.doi.org/10.3390/mi15010029.
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The carbonation of concrete greatly affects its service life. In this paper, fiber Bragg grating (FBG) sensors were used to investigate the relationship between concrete carbonation and its mechanical properties. A T130 High Sensitivity Strain Cable Sensor with a good linearity was used to monitor the internal strain in concrete, to investigate the variation in the elastic modulus of concrete with carbonation time. A mathematical model of elastic modulus and carbonation time of concrete based on FBG was established. At the same time, the authors explored the relationship between the carbonation depth and compressive strength of concrete and the carbonation time using a phenolphthalein solution test and a compressive strength test, respectively. The experimental results indicate that the carbonation depth, compressive strength, and elastic modulus of concrete increase with carbonation time. In the early stage of carbonation, these three parameters increase rapidly, while they grow slowly in the later stage of carbonation. The varying trend of the elastic modulus of concrete is consistent with the compressive strength, which shows a binomial relationship. Therefore, the elastic modulus, measured using FBG sensors, is used as an indicator of the characterization of the carbonation resistance of concrete. This work provides a new approach for concrete carbonation detection and assessment.
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Xu, Long, Fusheng Zha, Congmin Liu, Bo Kang, Jingjing Liu, and Chuang Yu. "Experimental Investigation on Carbonation Behavior in Lime-Stabilized Expansive Soil." Advances in Civil Engineering 2020 (February 24, 2020): 1–14. http://dx.doi.org/10.1155/2020/7865469.
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The carbonation behavior of lime-stabilized expansive soil is important for assessing the stabilization efficiency from the perspective of durability. In this study, the accelerated carbonation tests, measurement of pH value distribution, and the free swell ratio tests were conducted to investigate the evolutions of carbonation depth, carbonation extent, and expansive potential of lime-stabilized expansive soil. XRD, MIP, and SEM techniques were adopted as supplements to reveal the carbonation mechanism. Results demonstrated that the carbonation depth of lime-stabilized expansive soil increased significantly as time elapsed; however, the rate of increase reduced when the carbonation time increased. Higher carbonation depth was obtained at higher temperature and CO2 concentration and lower relative humidity, which was described by an empirical model. Fully, partly, and noncarbonated zones were subsequently presented with an increase in the depth of the soil. The expansive potential of lime-stabilized expansive soil was partially recovered during carbonation. The obtained linear relationships between the free swell ratio and pH value were adopted to describe the evolution of expansive behavior with carbonation time and depth. In microstructural analysis, the conversion of portlandite into calcium carbonate was significant, which resulted in changes in microstructure and controlled the carbonation behavior.
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Zhang, Dongsheng, Yafan Wang, Mingxiao Ma, Xiangjun Guo, Shuangquan Zhao, Shuxiang Zhang, and Qiuning Yang. "Effect of Equal Volume Replacement of Fine Aggregate with Fly Ash on Carbonation Resistance of Concrete." Materials 15, no. 4 (February 18, 2022): 1550. http://dx.doi.org/10.3390/ma15041550.
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Concrete is prepared by substituting an equal volume of fly ash for fine aggregate, and the effect of substitution rate on its carbonation resistance is studied. Using a rapid carbonation test, the distribution law of the internal pH value of concrete with fly ash as fine aggregate (CFA) along the carbonation depth under different substitution rates (10%, 20%, 30%, and 40%) after carbonation is studied and compared with the test results of phenolphthalein solution. Then, to further clarify the damage mechanism of fly ash replacing fine aggregate on concrete carbonation, the changes in the pore structure and micromorphology of CFA after carbonation are studied by means of mercury intrusion pressure and electron microscope scanning tests. The results indicate that the carbonation depth of CFA increases gradually with increasing carbonation time. In particular, in the later stage of carbonation, the carbonation rate of concrete decreases significantly with an increase in the substitution rate. The carbonation depth XC of CFA measured by phenolphthalein solution is approximately 0.24–0.39 times of the complete noncarbonation depth measured by the pH method. The pH value test is a reliable test method that can reveal the carbonation mechanism of CFA. Carbonation can significantly reduce the proportion of more harmful holes in concrete with a large amount of fly ash, but it can also increase the proportion of less harmful and harmful holes. In general, the pore size distribution and micromorphology of concrete can be improved by replacing fine aggregates with fly ash.
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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.
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Bui, Huyen, Francois Delattre, and Daniel Levacher. "Experimental Methods to Evaluate the Carbonation Degree in Concrete—State of the Art Review." Applied Sciences 13, no. 4 (February 16, 2023): 2533. http://dx.doi.org/10.3390/app13042533.
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The carbonation action in concrete, in which carbonation reactions transform calcium hydroxide into calcium carbonate, is considered as a multi-phase physico-chemical process. Generally, carbonation in the cementitious composites has negative effects on the protection of reinforced bars due to the accelerated corrosion problem. The investigation of the carbonation degree is, therefore, necessary to evaluate the carbonation influence on the reinforced cementitious composites. In the present paper, experimental techniques to measure the carbonation degree in concrete are reviewed, including both qualitative and quantitative methods. It should be noted that, while qualitative technique focuses on the alterations in the concrete pore solution alkalinity which reflects the carbonation depth through the pH indicator, most quantitative methods could provide accurate determination of the CO2 penetration capacity during the carbonation process. The method used, for the practical phase, depends on the purpose of the carbonation degree measurement.
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Li, Long, Dongxing Xuan, and Chi Sun Poon. "Stress–Strain Curve and Carbonation Resistance of Recycled Aggregate Concrete after Using Different RCA Treatment Techniques." Applied Sciences 11, no. 9 (May 9, 2021): 4283. http://dx.doi.org/10.3390/app11094283.
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Five recycled coarse aggregate (RCA) treatment techniques including flow-through carbonation, pressurized carbonation, wet carbonation, nano silica (NS) pre-spraying and combined pressurized carbonation with NS pre-spraying, were utilized to improve the performance of recycled aggregate concrete (RAC). The characteristics of the stress–strain curves of RACs including peak stress, peak strain, elastic modulus, ultimate strain and toughness were evaluated after using the above RCA treatment techniques. A theoretical model for natural aggregate concrete was used to analyse the stress–strain curve of RAC. Additionally, the carbonation resistance of RAC after using different RCA treatment techniques were investigated. The results showed that the calculated stress–strain curve of RAC based on the theoretical model matched well with the experimental results. Among the three types of carbonation techniques, pressurized carbonation caused the highest improvement in peak stress and elastic modulus of RAC, followed by flow-through carbonation, the last was wet carbonation. The NS pre-spraying method contributed to even higher improvement in peak stress and elastic modulus of RAC than the pressurized carbonation method. The combined pressurized carbonation with NS pre-spraying exhibited the highest enhancement of RAC because both the RCA and the new interface transition zone (ITZ) were improved. The carbonation resistance of RAC was improved after using all the studied RCA treatment techniques.
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Cao, Peiyu, Xin Zhao, Yutong Wang, Zeyu Zhang, and Jiaxiang Liu. "Effect of Glycine on the Wet Carbonation of Steel Slag Used as a Cementitious Material." Materials 17, no. 2 (January 17, 2024): 451. http://dx.doi.org/10.3390/ma17020451.
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The wet carbonation process of steel slag (SS) is envisaged to be an effective way to sequestrate CO2 and improve the properties of SS as a supplementary cementitious material. However, the carbonation process still struggles with having a low carbonation efficiency. This paper studied the effect of glycine on the accelerated carbonation of SS. The phase composition change of carbonated SS was analyzed via XRD, FT-IR, and TG–DTG. The carbonation process of SS is facilitated by the assistance of glycine, with which the carbonation degree is increased. After 60 min of carbonation, SS with glycine obtained a CO2 sequestration rate of 9.42%. Meanwhile, the carbonation reaction could decrease the content of free calcium oxide in SS. This significantly improves the soundness of SS–cement cementitious material, and the compressive strength of cementitious materials that contain carbonated SS with glycine is improved. Additionally, the cycling performance of glycine in the successive wet carbonation process of SS was investigated. Multicycle experiments via solvent recovery demonstrated that although the promotion effect of glycine was reduced after each cycle, compared with the SS–water system, the carbonation process could still be facilitated, demonstrating that successive wet carbonation via solvent recovery has considerable potential. Herein, we provide a new idea to facilitate the wet carbonation process of SS and improve the properties of SS–cement cementitious material.
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Li, Zhong Yuan, and Zhu Jun Wang. "Researches on Concrete Carbonation." Applied Mechanics and Materials 357-360 (August 2013): 737–42. http://dx.doi.org/10.4028/www.scientific.net/amm.357-360.737.
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The cause and prevention of concrete carbonation are core issues in the engineering community. With the improvement of the global CO2 concentration, more and more reinforced concrete buildings are faced with the problems of carbonation acceleration and following threats of steel corrosion which will heavily undermine the safety and durability of R.C. structures. The article from three major aspects, Concrete carbonation mechanism, causes of carbonation and carbonation influences, reviews and summarizes the current researches on carbonation and proposes valuable suggestions.
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Wang, Xiao Yong. "Evaluation Carbonation Service Life of Mortar-Coated Concrete Considering Global Warming." Materials Science Forum 1041 (August 4, 2021): 95–100. http://dx.doi.org/10.4028/www.scientific.net/msf.1041.95.
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Mortar finishing is frequently used to improve the carbonation service life of structural concrete. Moreover, carbonation is aggravated due to global warmings, such as the increase of CO2 concentration and temperature. This study shows a probability-based approach for evaluating the carbonation service life of coated concrete considering global warming. First, a carbonation model is proposed for assessing the carbonation depth of concrete with mortar finishing. The effect of global warming on carbonation is considered in the carbonation model. Second, a probability-based method is employed to determine the carbonation service life considering the thickness and mixtures of mortar finishing and substrate concrete. Based on the statistical analysis of calculation results, we find that for a concrete structural with 50 years’ service life, 15% service life will be reduced due to global warming.
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Nakamura, Eisuke, Yuki Kurihara, and Hirohisa Koga. "Outdoor Exposure Test of Concrete Containing Supplementary Cementitious Materials." Key Engineering Materials 711 (September 2016): 1076–83. http://dx.doi.org/10.4028/www.scientific.net/kem.711.1076.
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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.
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Mao, Mingjie, Dongsheng Zhang, Qiuning Yang, and Wenbo Zhang. "Study of Durability of Concrete with Fly Ash as Fine Aggregate under Alternative Interactions of Freeze-Thaw and Carbonation." Advances in Civil Engineering 2019 (April 16, 2019): 1–15. http://dx.doi.org/10.1155/2019/4693893.
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To study the durability of concrete with fly ash as fine aggregate subjected to alternative attacks of freeze-thaw and carbonation, the appearance, mass loss, relative dynamic modulus of elasticity, relative compressive strength, and carbonation depth of the concrete are investigated using cyclic tests under single carbonation, single freeze-thaw, and alternation of freeze-thaw and carbonation. In addition, microstructural analysis techniques including scanning electron microscope and X-ray diffraction are adopted to reveal the deterioration mechanism of alternating freeze-thaw and carbonation. Results show that carbonation is beneficial for refining the pore structure and increasing concrete strength in the initial alternative cycle, which delays the damage from freeze-thaw cycles. Damage from freeze-thaw causes crack propagation in concrete, which leads to carbonation intensification. Compared with other test modes, concrete under alternative freeze-thaw and carbonation causes the greatest degree of deterioration during the initial freeze-thaw cycles. The carbonation depth under alternative freeze-thaw and carbonation is positively correlated with the carbonation time and the water-to-cement ratio. However, as the reactant is continuously consumed due to the expansion of crystalline ice and CaCO3, alternative cycles result in the appearance of many more new cracks in the concrete.
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Pascuzzi, Edward. "Carbonation speculation." Physics Teacher 30, no. 3 (March 1992): 173. http://dx.doi.org/10.1119/1.2343501.
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Li, Guo, Ying Shu Yuan, Xin Liu, Jian Min Du, and Fu Min Li. "Influences of Environment Climate Conditions on Concrete Carbonation Rate." Advanced Materials Research 194-196 (February 2011): 904–8. http://dx.doi.org/10.4028/www.scientific.net/amr.194-196.904.
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Environment climate conditions are important influencing factors on concrete carbonation rates. Influences of concrete internal microclimate conditions including internal temperature (T) and relative humidity (RH) and external climate conditions including wind speed and wind direction on concrete carbonation rates were studied through laboratory accelerated carbonation experiments. Models based on concrete internal microclimate conditions were established. Results indicate that internal T always present accelerating effects on concrete carbonation rates, while internal RH and pore water saturation degree (PS) show hindering effects on it. Wind direction and wind speed have certain effects on concrete carbonation rate, and the higher wind speed, the higher concrete carbonation rate is. For the same wind speed, carbonation rate is the highest for perpendicular direction.
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Qi, Guang Zheng, Di Tao Niu, Cheng Fang Yuan, and Fu Zhen Duan. "Research on the Variation of pH Value of the Ordinary Concrete and Fly Ash Concrete in the Carbonation Process." Advanced Materials Research 374-377 (October 2011): 1934–37. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.1934.
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The accelerated carbonation test was carried out for the ordinary concrete and fly ash concrete. Influences of water-cement ratio, carbonation age and fly ash content on pH value were researched. The results show that carbonation depth, including incomplete carbonized zone, can be effectively reduced by reducing water-cement ratio. So lower water-cement ratio means high performance of resistance of carbonate. The use of fly ash can optimize concrete pore morphology, it’s beneficial for anti-carbonation. However, It disadvantageous to anti-carbonation because of less carbonation material. By taking appropriate mixture of fly ash we can not only enhance the anti-carbonation ability of concrete, but also reduce the use of cement to get well economic benefits.
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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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Zha, Xiao Xiong, and Shan Shan Cheng. "Numerical Simulation of Natural and Super-Critical Carbonation on Concrete Porous Brick." Advanced Materials Research 343-344 (September 2011): 112–15. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.112.
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Based on the partial differential equations on the carbonation of porous materials, this paper develops the natural and super-critical carbonation model by the multi-physics field coupling software to simulate and predict the relation between carbonation degree and the period of carbonation. It is shown that the carbonation degree after 1 day under super-critical condition is equivalent to that after 1 year under natural condition. The bidirectional carbonation makes the concrete porous brick carbonated faster than the concrete block, thus it is suitable for commercial production.
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Zhang, Lan Fang, Liu Yang, Bin Hong Fu, and Yu Yue. "Research Progress on Carbonation Resistance of Alkali-Activated Slag Cement Concrete." Materials Science Forum 1036 (June 29, 2021): 347–57. http://dx.doi.org/10.4028/www.scientific.net/msf.1036.347.
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The carbonation process in alkali-activated slag cement concrete is more complicated. This paper reviews the research progress of carbonation resistance of alkali-activated slag cement concrete at home and abroad and summarizes the existing research on carbonation. The focus is on the carbonation mechanism, test methods, influencing factors and the effect of carbonation on the performance of alkali-activated slag cement concrete. The problems existing in the current research on the anti-carbonation property of alkali-activated slag cement concrete and the issues for further research are proposed.
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Niu, Jian Gang, Liang Yan, and Hai Tao Zhai. "Study on the Influence of Freeze-Thaw on the Carbonation Property of Fly Ash Concrete." Applied Mechanics and Materials 357-360 (August 2013): 939–43. http://dx.doi.org/10.4028/www.scientific.net/amm.357-360.939.
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Based on the coupling testing program of freeze-thaw and carbonation, the laboratory simulation test is carried out. The laws of carbonation depth of the fly ash concrete suffered the freeze-thaw cycle in different test modes and the influence of fly ash dosage on concrete carbonation depth after the freeze-thaw cycle are studied. Defining the influence coefficient of the freeze-thaw cycles on carbonation depth of concrete, the mechanism of coupling of freeze-thaw and carbonation is analyzed,and the role of freeze-thaw and carbonation in the coupling process are obtained.
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Yang, Wen, Jun Wang, and Xi Xian Ji. "Accelerated Carbonation Test Equipment of Concrete." Key Engineering Materials 492 (September 2011): 455–58. http://dx.doi.org/10.4028/www.scientific.net/kem.492.455.
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Based on concrete carbonation test methods available and common carbonation test equipments, this article designed and developed a new concrete carbonation test equipment. The device consists of a gas storage tank and many independent small carbonation chambers. With a compact structure, the device is small, simple and practical. With its advantages of not only improving the CO2gas utilization, but also making full use of available space with the design of several smaller carbonation chambers, the device could carry out more carbonation tests without affecting their progresses. The device has a wide usage and promising future.
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Zhang, Hongzhi, Yingxuan Shao, Ning Zhang, Abdullah M. Tawfek, Yanhua Guan, Renjuan Sun, Changjin Tian, and Branko Šavija. "Carbonation Behavior of Engineered Cementitious Composites under Coupled Sustained Flexural Load and Accelerated Carbonation." Materials 15, no. 18 (September 6, 2022): 6192. http://dx.doi.org/10.3390/ma15186192.
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Engineered cementitious composites (ECCs) belong to a broad class of fibre-reinforced concrete. They incorporate synthetic polyvinyl alcohol (PVA) fibres, cement, fly ash and fine aggregates, and are designed to have a tensile strain capacity typically beyond 3%. This paper presents an investigation on the carbonation behaviour of engineered cementitious composites (ECCs) under coupled sustained flexural load and accelerated carbonation. The carbonation depth under a sustained stress level of 0, 0.075, 0.15, 0.3 and 0.6 relative to flexural strength was measured after 7, 14 and 28 days of accelerated carbonation. Thermogravimetric analysis, mercury intrusion porosimetry and microhardness measurements were carried out to show the coupled influence of sustained flexural load and accelerated carbonation on the changes of the mineral phases, porosity, pore size distribution and microhardness along the carbonation profile. A modified carbonation depth model that can be used to consider the coupled effect of flexural tensile stress and carbonation time was proposed. The results show that an exponential relationship can be observed between stress influence coefficient and flexural tensile stress level in the carbonation depth model of ECC, which is different when using plain concrete. Areas with a higher carbonation degree have greater microhardness, even under a large sustained load level, as the carbonation process refines the pore structure and the fibre bridges the crack effectively.
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Nielsen, Peter, and Mieke Quaghebeur. "Determination of the CO2 Uptake of Construction Products Manufactured by Mineral Carbonation." Minerals 13, no. 8 (August 14, 2023): 1079. http://dx.doi.org/10.3390/min13081079.
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Mineral carbonation is a technology for capturing and storing CO2 in solid minerals. When mineral carbonation is used to produce construction materials, the quantification of the CO2 uptake of these products is of the utmost importance, as it is used to calculate the CO2 footprint of the product and/or carbon offset. The CO2 uptake is generally determined by measuring the CO2 content of a material before and after accelerated carbonation. This approach, however, does not take hydration and dehydroxylation reactions into account that may occur during carbonation, and it can therefore under- or overestimate the CO2 uptake. Thus, a more accurate and practical method to determine CO2 uptake, which also accounts for hydration and dehydroxylation reactions, is proposed in this paper. This method is based on analytical methods to determine the dry mass and the CO2 content of the solid products before and after carbonation, and on the calculation of the CO2 uptake by the following equation: CO2 uptake (wt.%) = CO2 carbonated (wt.%) × (weight after carbonation (g)/weight before carbonation (g) − CO2 initial (wt.%), with CO2 carbonated being the CO2 content in g/100 g dried carbonated material, and CO2 initial being the CO2 content in g/100 g dried initial material, i.e., before carbonation. The “weight before carbonation” is the dry weight of the initial material, and the “weight after carbonation” is the product’s dry weight after carbonation. In this paper, we show that up to 44% under- or overestimation of CO2 uptake can occur when hydration and dehydroxylation reactions are not taken into account during mineral carbonation.
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Zhang, Shi Ping, Lan Zong, Liang Feng Dong, and Wei Zhang. "Influence of Cracking on Carbonation of Cement-Based Materials." Advanced Materials Research 261-263 (May 2011): 84–88. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.84.
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In this paper, a method for measuring carbonation depth of cracked samples was introduced, and experiments have been carried out to determine the extent of carbonation through a crack. Comparison of the carbonation in sound concrete and in cracked concrete has been suggested. The experiment conducted to demonstrate that crack will accelerate the carbonation of concrete, and increasing crack width allows more penetration of the carbonation reaction for three kinds of penetration mentioned in the paper. Carbonation depth penetration into the sample from exposed face increase rapidly, when the crack width increases from 0 to 0.1 mm. Carbonation degree of the cracked sample is greater than that of the sound sample at the same site according to the results of calcium carbonate contents.
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Miao, Chen, Bing Quan Sun, Li Wang, and Da Wei Zhang. "Carbonation Property and Prediction of Concrete Mixed with Alkaline Potential Water." Applied Mechanics and Materials 584-586 (July 2014): 1161–64. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.1161.
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This study investigates carbonation properties of concrete mixed with alkaline potential water (APW). A miniature electrolyzer made up of diaphragm electrolytic cells was made to produce APW. Results show that APW concrete gains greatly in carbonation property - carbonation depth deepened by 21% in the 28day fast carbonation test. A new mold is developed to make concrete samples with spherical concaves which promised a smooth test surface to the sample, realizing the lossless test of concrete carbonation. A long term carbonation test (90 days) of concrete mixed with ARPW is carried out. Applying grey system theory, the time dependence rule, which decides the dynastic model of carbonation formula is studied, offering a more scientific basis for estimating the structural durability of concrete. <br />
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Zhao, Quan Feng, Jian Wu, and Yao Chun Yao. "Effect of Carbonation Temperature on the Purification of Lithium Carbonate." Advanced Materials Research 846-847 (November 2013): 1911–14. http://dx.doi.org/10.4028/www.scientific.net/amr.846-847.1911.
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High-purity Li2CO3was purified and prepared by carbonation decomposition method using industrial Li2CO3as raw material. The effects of carbonation temperature on the purity, productivity and the removal of impurities containing Ca, Mg, Fe, Cu and Ni in purification process were investigated. The results shown that high carbonation temperature didnt benefit the purity and productivity of Li2CO3. The content of Mg decreased with the increase of carbonation temperature. The other impurities, such as Ca, Fe, Cu and Ni, had no obvious change with the increase of carbonation temperature. The optimum carbonation temperature was determined as 25°C.
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Czarnecki, L., and P. Woyciechowski. "Modelling of concrete carbonation; is it a process unlimited in time and restricted in space?" Bulletin of the Polish Academy of Sciences Technical Sciences 63, no. 1 (March 1, 2015): 43–54. http://dx.doi.org/10.1515/bpasts-2015-0006.
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Abstract The aim of the article is mathematical modelling of the carbonation process that has been based on results of research conducted both in accelerated and natural conditions. The article covers short characteristic of carbonation, its processes and effects. Also critical review of articles that concern carbonation mathematical models was included in the paper. Assuming the self-terminating nature of carbonation the hyperbolic model of carbonation was formulated. Such a model describes the carbonation progress as the process unlimited in time but with the restricted range in concrete depth that is limited by the value of a model asymptote. Presented results cover research on carbonation of concrete with a different water-cement ratio and different types of binders and duration times of early curing. Investigations have been conducted as accelerated (1% concentration of CO2) as well as in long-term exposures in natural conditions. The obtained results confirmed statistically that hyperbolic model is a well-founded approach when the modelling concrete carbonation process is concerned
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Si, Xiuyong, and Huimin Pan. "Effects of supplementary cementitious material(SCM) on carbonation resistance of concrete." Advances in Engineering Technology Research 7, no. 1 (August 14, 2023): 313. http://dx.doi.org/10.56028/aetr.7.1.313.2023.
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Using fly ash (FA) and ground granulated blast furnace slag (GGBS) as representatives of supplementary cementitious material (SCM), the effects of the amount and combination of SCM addition on the carbonation resistance of concrete were systematically analyzed through rapid carbonation tests. Combined with XRD chemical analysis and DSC-TG thermogravimetric analysis, the influence mechanism of SCM on the carbonation resistance of concrete was discussed. The research results indicate that the addition of SCM increases the carbonation depth of concrete.
When the single addition of FA exceeds 40%, the carbonation depth of concrete increases very quickly. Under the premise of the same total addition amount, the carbonation resistance performance of the composite FA and GGBS groups of concrete is better than that of the single FA group. Among the different combinations of FA and GGBS, the concrete with S95 grade GGBS+ grade I FA has the best carbonation resistance. The impact of FA on the carbonation resistance of concrete is manifested as a positive and negative effect.
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Yang, Shiqing, Mingjie Gu, Hongyi Lin, and Yue Gong. "Property Improvement of Recycled Coarse Aggregate by Accelerated Carbonation Treatment under Different Curing Conditions." Sustainability 15, no. 6 (March 9, 2023): 4908. http://dx.doi.org/10.3390/su15064908.
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Recycled aggregate (RA) made from waste concrete has inferior fundamental properties, i.e., apparent density, water absorption, mass variation, carbonation ratio, etc., compared to those of natural aggregate (NA), severely restricting its application in practical projects. However, using CO2 to accelerate RA carbonation can effectively improve these properties, and this treatment approach can promote energy savings and sustainable development. The accelerated carbonation curing conditions for RA can significantly impact the modification effect of RA. For this purpose, this paper used recycled coarse aggregate (RCA) as a case study. An accelerated carbonation modification treatment experiment for RCA under different accelerated carbonation curing conditions was carried out, and the effects of relative humidity and CO2 concentration on the apparent density, water absorption, moisture content, mass variation and carbonation ratio of RCA under a constant ambient temperature were explored and quantified. The results indicated that the best-accelerated carbonation curing conditions applicable to this paper’s RCA were confirmed as being an environmental temperature of 20 °C and a relative humidity of 70%, as well as a CO2 concentration of 20%. Under these conditions, the apparent density and water absorption of CRCA are approximately 1.04 times and 75.30% higher than those of RCA, and, in addition, the carbonation ratio for RCA under the optimal accelerated carbonation curing conditions is all higher than others, thus improving the properties of RCA to a certain degree. Finally, in this paper, the variation trends of the RCA property indexes in terms of carbonation time treated by the best accelerated carbonation curing conditions are examined, and the time-varying models for the RCA property indexes during the accelerated carbonation are established.
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Tao, Meng-Jie, Ya-Jun Wang, Jun-Guo Li, Ya-Nan Zeng, Shao-Hua Liu, and Song Qin. "Slurry-Phase Carbonation Reaction Characteristics of AOD Stainless Steel Slag." Processes 9, no. 12 (December 16, 2021): 2266. http://dx.doi.org/10.3390/pr9122266.
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Argon oxygen decarburization stainless steel slag (AOD slag) has high mineral carbonation activity. AOD slag carbonation has both the resource utilization of metallurgical waste slag and the carbon reduction effect of CO2 storage. This paper aimed to study carbonation reaction characteristics of AOD slag. Under the slurry-phase accelerated carbonation route, the effect of stirring speed (r) and reaction temperature (T) on AOD slag’s carbonation was studied by controlling the reaction conditions. Mineral composition analysis and microscopic morphology analysis were used to explore the mineral phase evolution of AOD slag during the carbonation process. Based on the unreacted core model, the kinetic model of the carbonation reaction of AOD slag was analyzed. The results showed that the carbonation ratio of AOD slag reached its maximum value of 66.7% under the reaction conditions of a liquid to solid ratio (L/S) of 8:1, a CO2 partial pressure of 0.2 MPa, a stirring speed of 450 r·min−1, and a reaction temperature of 80 °C. The carbonation reaction of AOD slag was controlled by internal diffusion, and the calculated apparent activation energy was 22.28 kJ/mol.
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Xu, Lina, Yan Zhang, Shuyuan Zhang, Shuyuan Fan, and Honglei Chang. "Effect of Carbonation on Chloride Maximum Phenomena of Concrete Subjected to Cyclic Wetting–Drying Conditions: A Numerical and Experimental Study." Materials 15, no. 8 (April 14, 2022): 2874. http://dx.doi.org/10.3390/ma15082874.
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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.
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Tang, Wei Le, Han-Seung Lee, Vanissorn Vimonsatit, Trevor Htut, Jitendra Kumar Singh, Wan Nur Firdaus Wan Hassan, Mohamed A. Ismail, Asiful H. Seikh, and Nabeel Alharthi. "Optimization of Micro and Nano Palm Oil Fuel Ash to Determine the Carbonation Resistance of the Concrete in Accelerated Condition." Materials 12, no. 1 (January 3, 2019): 130. http://dx.doi.org/10.3390/ma12010130.
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The carbonation rate of reinforced concrete is influenced by three parameters, namely temperature, relative humidity, and concentration of carbon dioxide (CO2) in the surroundings. As knowledge of the service lifespan of reinforced concrete is crucial in terms of corrosion, the carbonation process is important to study, and high-performance durable reinforced concretes can be produced to prolong the effects of corrosion. To examine carbonation resistance, accelerated carbonation testing was conducted in accordance with the standards of BS 1881-210:2013. In this study, 10–30% of micro palm oil fuel ash (mPOFA) and 0.5–1.5% of nano-POFA (nPOFA) were incorporated into concrete mixtures to determine the optimum amount for achieving the highest carbonation resistance after 28 days water curing and accelerated CO2 conditions up to 70 days of exposure. The effect of carbonation on concrete specimens with the inclusion of mPOFA and nPOFA was investigated. The carbonation depth was identified by phenolphthalein solution. The highest carbonation resistance of concrete was found after the inclusion of 10% mPOFA and 0.5% nPOFA, while the lowest carbonation resistance was found after the inclusion of 30% mPOFA and 1.5% nPOFA.
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Liu, Wei, Shifa Lin, Yongqiang Li, Wujian Long, Zhijun Dong, and Luping Tang. "Slag Blended Cement Paste Carbonation under Different CO2 Concentrations: Controls on Mineralogy and Morphology of Products." Materials 13, no. 15 (August 1, 2020): 3404. http://dx.doi.org/10.3390/ma13153404.
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To investigate the effect of different CO2 concentrations on the carbonation results of slag blended cement pastes, carbonation experiments under natural (0.03% CO2) and accelerated conditions (3, 20, and 100% CO2) were investigated with various microscopic testing methods, including X-ray diffraction (XRD), 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR) and scanning electron microscopy (SEM). The XRD results indicated that the major polymorphs of CaCO3 after carbonation were calcite and vaterite. The values of the calcite/(aragonite + vaterite) (c/(a + v)) ratios were almost the same in all carbonation conditions. Additionally, NMR results showed that the decalcification degree of C-S-H gel exposed to 0.03% CO2 was less than that exposed to accelerated carbonation; under accelerated conditions, it increased from 83.1 to 84.2% when the CO2 concentration improved from 3% to 100%. In SEM observations, the microstructures after accelerated carbonation were denser than those under natural carbonation but showed minor differences between different CO2 concentrations. In conclusion, for cement pastes blended with 20% slag, a higher CO2 concentration (above 3%) led to products different from those produced under natural carbonation. A further increase in CO2 concentration showed limited variation in generated carbonation products.
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Chen, Chunhong, Ronggui Liu, Pinghua Zhu, Hui Liu, and Xinjie Wang. "Carbonization Durability of Two Generations of Recycled Coarse Aggregate Concrete with Effect of Chloride Ion Corrosion." Sustainability 12, no. 24 (December 16, 2020): 10544. http://dx.doi.org/10.3390/su122410544.
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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.
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Liu, Yan Jun, Bo Tian Chen, and Yong Chao Zheng. "Thermodynamic Interpretation of Carbonation Process of Portland Cement Hydration Products." Advanced Materials Research 753-755 (August 2013): 543–57. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.543.
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Cement hydration products carbonation is not only blamed for the carbonation-induced hardened cement paste or concrete cracking, also attributed to the pore water PH-value decrease, which causes the reinforcement corrosion under the existence of water and oxygen due to removal of oxide film passivating rebar surface, in hardened cement paste and concrete. Based on chemical thermodynamics, this paper presents the susceptibility of different cement hydration products to carbonation through calculating their Standard Gibbs Free Energy respectively, Gibbs free energy under temperature variation and the minimum equilibrium pressure of carbon dioxide triggering the carbonation process. The calculated results show that, under standard state (25°C, 100kpa), the minimum equilibrium pressure of carbon dioxide triggering carbonation process is significantly variable for different types of cement hydration products. For example, mono-sulfate sulfoferrite hydrates (3CaOFe2O3CaSO412H2O) is the most susceptible to carbonation, followed by mono-sulfate aluminate hydrates (3CaOAl2O3CaSO412H2O), while multi-sulfate sulfoaluminate hydrates (3CaOAl2O33CaSO432H2O) is the least vulnerable to carbonation, followed by silicate hydrates (5CaO6SiO25.5H2O). The findings in this paper are significant in understanding thermodynamic mechanism of cement hydrates carbonation and seeking the solution to prevent cement hydrates from carbonation-induced deterioration.
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Hwalla, Joud, Mahra Al-Mazrouei, Khalood Al-Karbi, Afraa Al-Hebsi, Mariam Al-Ameri, Fatima Al-Hadrami, and Hilal El-Hassan. "Performance of Alkali-Activated Slag Concrete Masonry Blocks Subjected to Accelerated Carbonation Curing." Sustainability 15, no. 19 (September 27, 2023): 14291. http://dx.doi.org/10.3390/su151914291.
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This study investigates the effect of accelerated carbonation curing on the carbon sequestration potential, performance, and microstructure of alkali-activated slag mixes representing concrete masonry blocks (CMBs). The carbonation curing process parameters varied, including initial curing duration, carbonation curing duration, and carbonation pressure. Research findings showed that a maximum CO2 uptake of 12.8%, by binder mass, was attained upon exposing concrete to 4 h initial curing and 20 h carbonation curing at a pressure of 5 bars. The compressive strength and water absorption capacity improved with longer initial and carbonation curing durations and higher pressure. Upon subjecting to salt attack, the mass and strength of 28-day concrete samples increased, owing to the formation of Friedel’s salt and Halite. All mixes could be used as non-load-bearing CMB, with a 1-day strength greater than 4.1 MPa. Based on the global warming potential index, the carbon footprint of carbonation-cured, alkali-activated slag concrete masonry units was up to 46% lower than non-carbonation-cured counterparts. Research findings offer valuable information on the production of carbonation-cured, cement-free concrete masonry blocks to replenish natural resources, recycle industrial waste, and mitigate CO2 emissions.
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Pourhaji, Pardis, Pedro Serna, and Maria Cruz Alonso. "Effect of autogenous healing of narrow and wide cracks on the progression of carbonation in the walls of cracks." MATEC Web of Conferences 378 (2023): 06003. http://dx.doi.org/10.1051/matecconf/202337806003.
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This paper deals with the carbonation of concrete crack walls before and after healing in comparison to the carbonation of the bulk of the concrete. Natural carbonation tests were carried out on 50 MPa concrete. Disks with 50 mm thickness and 100 mm diameter were tested. A splitting test was applied to generate the crack. Different crack widths were tested, narrow crack widths below 75μm, and wide crack widths, between 75-175μm. The self-healing effect was studied after immersion for 4 months in water. Natural carbonation was carried out at 55±5 %RH 20±3°C for 6, 9 and 12 months. The carbonation front was assessed after splitting and opening the crack walls. The results show the effect of the crack width, crack length and autogenous healing that affect the progression of carbonation in the crack walls. The carbonation in the crack wall is at least twice that of the concrete. Crack widths larger than 75μm carbonate faster. Autogenous healing of the narrow cracks can reduce the carbonation front at the crack walls with compare to the unhealed narrow; however, no improvement was observed in limiting the carbonation front in the crack walls of healed wide cracks.
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Zhang, Yangyang, Hang Yang, Qunli Zhang, Quan Qian, Chengwei Zhang, Kai Wu, and Peiliang Shen. "Microstructural Evolution of Calcium Sulfoaluminate Cement during the Wet-Carbonation Process." Buildings 14, no. 2 (January 26, 2024): 343. http://dx.doi.org/10.3390/buildings14020343.
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Calcium sulfoaluminate (CSA) cement, as a type of low-carbon cement, can contribute to further reduction in carbon emissions with carbonation technologies. However, the detailed microstructure development of CSA cement during the carbonation process has been rarely analyzed. In this paper, wet carbonation was applied to CSA cement to investigate the microstructure evolution of carbonation products and carbon absorption capacity of CSA cement by means of pH measurement, X-ray diffraction (XRD) measurement, thermogravimetric (TG) measurement, Fourier-transformed infrared spectroscopy (FT-IR) measurement and scanning electron microscope measurement. During the carbonation process, the formed ettringite product and the dicalcium silicate clinker were carbonated immediately to generate calcium carbonate crystals, silica gel and aluminum hydroxide (AH3) gel. With the trend of pH increasing first and notably decreasing later, the coupling interaction between the hydration and carbonation reactions of CSA cement was revealed. From the XRD and TG results, three types of calcium carbonate crystal forms (calcite, vaterite and aragonite) were detected, and the content of calcium carbonate increased with the increase in carbonation time. FT-IR analysis further confirmed the existence of calcium carbonate, silica gel and AH3 gel with their characteristic vibrations. Moreover, the microstructure of carbonation products with different morphologies was observed. The application of wet carbonation to CSA cement provides a more comprehensive insight to the carbonation mechanism of this low-carbon cement.
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Reddy, Kamasani Chiranjeevi, Nahom S. Melaku, and Solmoi Park. "Thermodynamic Modeling Study of Carbonation of Portland Cement." Materials 15, no. 14 (July 20, 2022): 5060. http://dx.doi.org/10.3390/ma15145060.
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The assessment of the extent of carbonation and related phase changes is important for the evaluation of the durability aspects of concrete. The phase assemblage of Portland cements with different clinker compositions is evaluated using thermodynamic calculations. Four different compositions of cements, as specified by ASTM cements types I to IV, are considered in this study. Calcite, zeolites, and gypsum were identified as carbonation products. CO2 content required for full carbonation had a direct relationship with the initial volume of phases. The CO2 required for portlandite determined the initiation of carbonation of C-S-H. A continual decrease in the pH of pore solution and a decrease in Ca/Si is observed with the carbonation of C-S-H. Type II cement exhibited rapid carbonation at relatively less CO2for full carbonation, while type III required more CO2 to carbonate to the same level as other types of cement. The modeling of carbonation of different Portland cements provided insights into the quantity of CO2 required to destabilize different hydrated products into respective carbonated phases.
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Chen, Ying, Peng Liu, and Zhiwu Yu. "Effects of Environmental Factors on Concrete Carbonation Depth and Compressive Strength." Materials 11, no. 11 (November 2, 2018): 2167. http://dx.doi.org/10.3390/ma11112167.
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The influence of temperature, CO2 concentration and relative humidity on the carbonation depth and compressive strength of concrete was investigated. Meanwhile, phase composition, types of hydration products and microstructure characteristics of samples before and after the carbonation were analyzed by XRD and ESEM. Research results demonstrate that temperature, CO2 concentration and relative humidity influence the carbonation depth and compressive strength of concrete significantly. There is a linear relationship between temperature and carbonation depth, as well as the compressive strength of concrete. CO2 concentration and relative humidity present a power function and a polynomial function with carbonation depth of concrete, respectively. The concrete carbonation depth increases with the increase of relative humidity and reaches the maximum value when the relative humidity is 70%. Significant differences of phase composition, hydration products and microstructure are observed before and after the carbonation. Carbonization products of samples are different with changes of temperatures (10 °C, 20 °C and 30 °C). The result of crystal structure analysis indicates that the carbonation products are mainly polyhedral spherical vaterite and aragonite.