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Balestra, Carlos Eduardo Tino, Gustavo Savaris, Alberto Yoshihiro Nakano i Ricardo Schneider. "Carbonation of concretes containing LC³ cements with different supplementary materials". Semina: Ciências Exatas e Tecnológicas 43, nr 2 (27.12.2022): 161–70. http://dx.doi.org/10.5433/1679-0375.2022v43n2p161.
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Due to the clinkerization process during the Portland cement production, large amounts of CO2 are emitted, increasing the effects related to climate change (approximately 5-10% of global CO2 emissions come from cement production), consequently, the seek for alternatives to mitigate these high emissions are necessary. The use of supplementary cementitious materials (SCM) to partial replace of Portand clinker/cement has been the subject of different research, including the use of LC3 cements (Limestone Calcined Clay Cements), where up to 50% of Portland clinker can be replaced, however, cement industry has already used othersupplementary cementitious materials with pozzolanic activities in commercial cements. In this sense, this work evaluates the performance of concretes containing LC3 mixtures with the presence of different SCM (silica fume, fly ash, sugarcane bagasse ash and açaí stone ash) regarding durability issues by carbonation. The results showed that all concretes with LC3 presented higher carbonation fronts in relation to the reference concrete, with Portland cement, due to the lower availability of calcium to react with the CO2 that penetrates into the concrete pores, so the adoption of curing procedures and coatings are recommended.
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Rita Damasceno Costa, Ana, i Jardel Pereira Gonçalves. "Accelerated carbonation of ternary cements containing waste materials". Construction and Building Materials 302 (październik 2021): 124159. http://dx.doi.org/10.1016/j.conbuildmat.2021.124159.
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Shah, Vineet, i Shashank Bishnoi. "Carbonation resistance of cements containing supplementary cementitious materials and its relation to various parameters of concrete". Construction and Building Materials 178 (lipiec 2018): 219–32. http://dx.doi.org/10.1016/j.conbuildmat.2018.05.162.
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Cornejo, M. H., J. Elsen, C. Paredes i H. Baykara. "Hydration and strength evolution of air-cured zeolite-rich tuffs and siltstone blended cement pastes at low water-to-binder ratio". Clay Minerals 50, nr 1 (marzec 2015): 133–52. http://dx.doi.org/10.1180/claymin.2015.050.1.12.
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AbstractThis contribution is the second part of an in-depth study on the hydration and strength evolution of blended cement pastes at a water to binder (W/B) ratio of 0.3, cured by two different methods. The blended cement pastes showed significant hydration up to 7 days, when almost all of the hydration products had already formed; thereafter, carbonation played an important role up to, and possibly beyond, 91 days. Likewise, the hydration of alite (tricalcium silicate, Ca3SiO5, C3S) proceeded up to 14 days and then started to slow down. However, the hydration of belite (dicalcium silicate, Ca2SiO4, C2S) was affected most strongly, as it nearly ceased, under the air-curing conditions. During hydration, some of the blended cement pastes had a larger calcium hydroxide (CH) content than the unblended (plain) ones. The accelerating effects of the addition of supplementary cementitious materials (SCMs), the air-curing conditions and the low W/B ratio may explain these unusual results. Under these experimental conditions, the water incorporated into hydrates was about 50% of the total amount of water used during full hydration of the cement pastes. The pozzolanic reaction predominated during the early ages, but disappeared as time passed. In contrast, the carbonation reaction increased by consuming ∼45% of the total amount of CH produced after aging for 91 days. Only one blended cement paste reached the compressive strength of the plain cements. The blended cement pastes containing 5% of the zeolitic tuffs, Zeo1 or Zeo2, or 10% of the calcareous siltstone, Limo, developed the greatest compressive strength under the experimental conditions used in this study.
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Homayoonmehr, Reza, Ali Akbar Ramezanianpour, Faramarz Moodi, Amir Mohammad Ramezanianpour i Juan Pablo Gevaudan. "A Review on the Effect of Metakaolin on the Chloride Binding of Concrete, Mortar, and Paste Specimens". Sustainability 14, nr 22 (14.11.2022): 15022. http://dx.doi.org/10.3390/su142215022.
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Chloride binding is a complex phenomenon in which the chloride ions bind with hydrated Portland cement (PC) phases via physical and chemical mechanisms. However, the current utilization of clays as (Al)-rich supplementary cementitious materials (SCMs), such as metakaolin (MK), can affect the chloride-binding capacity of these concrete materials. This state-of-the-art review discusses the effect of clay-based SCMs on physical and chemical chloride binding with an emphasis on MK as a high-reactivity clay-based SCM. Furthermore, the potential mechanisms playing a role in physical and chemical binding and the MK effect on the hydrated cement products before and after exposure to chloride ions are discussed. Recent findings have portrayed competing properties of how MK limits the physical chloride-binding capacity of MK-supplemented concrete. The use of MK has been found to increase the calcium silicate hydrates (CSH) content and its aluminum to silicon (Al/Si) ratio, but to reduce the calcium to silicon (Ca/Si) ratio, which reduces the physical chloride-binding capacity of PC-clay blended cements, such as limestone calcined clay cements (LC3). By contrast, the influence of MK on the chemical chloride capacity is significant since it increases the formation of Friedel’s salt due to an increased concentration of Al during the hydration of Portland cement grains. Recent research has found an optimum aluminum to calcium (Al/Ca) ratio range, of approximately 3 to 7, for maximizing the chemical binding of chlorides. This literature review highlights the optimal Al content for maximizing chloride binding, which reveals a theoretical limit for calcined clay addition to supplementary cementitious materials and LC3 formulations. Results show that 5–25% of replacements increase bound chloride; however, with a higher percentage of replacements, fresh and hardened state properties play a more pivotal role. Lastly, the practical application of four binding isotherms is discussed with the Freundlich isotherm found to be the most accurate in predicting the correlation between free and bound chlorides. This review discusses the effects of important cement chemistry parameters, such as cation type, sulfate presence, carbonation, chloride concentration, temperature, and applied electrical fields on the chloride binding of MK-containing concretes—important for the durable formulation of LC3.
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Li, Haoyuan, Zhonghe Shui, Ziyan Wang i Xunguang Xiao. "Effects of UV Radiation on the Carbonation of Cement-Based Materials with Supplementary Cementitious Materials". Coatings 13, nr 6 (26.05.2023): 994. http://dx.doi.org/10.3390/coatings13060994.
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Solar light with high-energy ultraviolet (UV) radiation acting on the surface of cement-based materials easily changes the properties of cement-based materials by affecting their carbonation reaction. In order to elucidate the difference in the carbonation process under UV radiation in cement-based materials with different supplementary cementitious materials (SCMs), the carbonation depth (apparent pH values), chemical composition (XRD, FTIR, and TG analysis), and mechanical properties (compressive strength and microhardness) of cement-based materials were evaluated. The results revealed that UV radiation acting on the surface of cement-based materials accelerated the carbonation reaction, which enhanced the decrease rate of pH and formation of stable calcite, thereby improving the macromechanical and micromechanical properties of cement-based materials. In addition, the carbonation process under UV radiation differs according to the added SCM. In particular, silica fume substantially increased the carbonation of cement-based materials under UV radiation, resulting in a 53.3% increase in calcium carbonate coverage, a 10.0% increase in compressive strength, and a 20.9% increase in mean microhardness, whereas the incorporation of blast furnace slag resulted in a smaller effect on UV irradiation-induced carbonation. In addition, UV radiation facilitates the crystallographic transformation process of cement-based materials containing metakaolin, resulting in more stable crystals of carbonation products. This study provides a theoretical framework and serves as an important reference for the design of cement-based materials under strong UV radiation for practical engineering applications.
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Pokorný, Jaroslav, Milena Pavlíková i Zbyšek Pavlík. "Effect of CO2 Exposure on Mechanical Resistivity of Cement Pastes with Incorporated Ceramic Waste Powder". Materials Science Forum 824 (lipiec 2015): 133–37. http://dx.doi.org/10.4028/www.scientific.net/msf.824.133.
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Carbonation is chemical process associated with CO2penetration into the material porous structure causing subsequent chemical changes in the structure of cement pastes. In this work, carbonation of several pastes containing varying amount of cement replacement by three waste ceramic powders is studied. Chemical composition of particular tested materials is accessed using XRF analysis. Matrix density, bulk density, total open porosity, compressive and bending strength are measured for all developed pastes with incorporated ceramic materials. Simultaneously, the effect of carbonation on these material properties is researched. The obtained results show significant improvement of materials mechanical strength due to the carbonation. Here, the measured compressive strength is typically about ~ 60% higher for materials exposed to CO2rich environment compared to the materials cured in laboratory conditions.
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STAŃCZYK, DOMINIKA, i BEATA JAWORSKA. "INFLUENCE OF AGRICULTURAL BIOMASS FLY ASH CEMENT SUBSTITUTION ON THE CARBONATION OF CEMENT AND POLYMER-CEMENT COMPOSITES". Structure and Environment 12, nr 2 (30.06.2020): 66–71. http://dx.doi.org/10.30540/sae-2020-007.
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Practical use of a new type of combustion waste such as an agricultural biomass fly ash in the building materials requires an assessment of its performance. The paper presents the investigation results on the influence of cement substitution (5% and 30%) by this ash on the cement and polymer-cement composites resistance to carbonation. The composites resistance was assessed on the basis of carbonation process over time (up to 360 days) using the phenolphthalein method. It was found that fly ash from agricultural biomass increases the susceptibility to carbonation of polymer-cement composites to a lesser extent than cement composites compared to composites containing siliceous coal fly ash.
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Kim, Min-Sung, Sang-Rak Sim i Dong-Woo Ryu. "Supercritical CO2 Curing of Resource-Recycling Secondary Cement Products Containing Concrete Sludge Waste as Main Materials". Materials 15, nr 13 (29.06.2022): 4581. http://dx.doi.org/10.3390/ma15134581.
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This study aims to develop highly durable, mineral carbonation-based, resource-recycling, secondary cement products based on supercritical carbon dioxide (CO2) curing as part of carbon capture utilization technology that permanently fixes captured CO2. To investigate the basic characteristics of secondary cement products containing concrete sludge waste (CSW) as the main materials after supercritical CO2 curing, the compressive strengths of the paste and mortar (fabricated by using CSW as the main binder), ordinary Portland cement, blast furnace slag powder, and fly ash as admixtures were evaluated to derive the optimal mixture for secondary products. The carbonation curing method that can promote the surface densification (intensive CaCO3 formation) of the hardened body within a short period of time using supercritical CO2 curing was defined as “Lean Carbonation.” The optimal curing conditions were derived by evaluating the compressive strength and durability improvement effects of applying Lean Carbonation to secondary product specimens. As a result of the experiment, for specimens subjected to Lean Carbonation, compressive strength increased by up to 12%, and the carbonation penetration resistance also increased by more than 50%. The optimal conditions for Lean Carbonation used to improve compressive strength and durability were found to be 35 °C, 80 bar, and 1 min.
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Hussin, Muhamad Hasif, Nor Hazurina Othman i Mohd Haziman Wan Ibrahim. "Carbonation of concrete containing mussel (Perna viridis) shell ash". Journal of Engineering, Design and Technology 17, nr 5 (10.08.2019): 904–28. http://dx.doi.org/10.1108/jedt-12-2018-0228.
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Purpose This paper aims to investigate the use of calcined mussel shell (CMS) ash–cement mix in concrete that is found to increase the concrete resistance against carbonation. Design/methodology/approach The deposited ash from the calcination of the mussel shells at 1000°C was used to replace the ordinary Portland cement at 5 and 7 per cent of the cement weight. The test results from the control concrete specimens were compared to the test results from the experimental concrete specimens to analyse the effects due to the said replacements. Carbonation was carried out naturally in the environment where the concentration of the carbon dioxide gas was at 0.03 per cent, the relative humidity of 65 per cent and the temperature of 27°C for a maximum period of 120 days. Measurement of carbonation depth was taken in accordance to the BS EN 13295: 2004. The carbonation resistance of the concrete was assessed based on the degree of compliance with the common design life requirement of 50 years. The filler effect from the CMS was verified using the capillary absorption test (ASTM C1585: 2013) and the electron microscope. Findings Experimental concrete specimens containing 5 and 7 per cent of the CMS ash demonstrated better carbonation resistance compared to the control concrete specimens with a minimum attainable design life of 56 years which can reach a maximum of 62 years. Capillary absorption test results indicated that the concrete pores have been effected by the said filler effect and visual observation from the electron microscope confirmed, solidifying the statement. Originality/value The CMS ash is proven to contribute to the concrete’s resistance against carbonation. Also, the CMS ash is synthesized from waste materials which have contributed to the application of the green material in the concrete technology.
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Chen, Zhengxin, Yunsu Lee, Hyeongkyu Cho, Hanseung Lee i Seungmin Lim. "Improvement in Carbonation Resistance of Portland Cement Mortar Incorporating γ-Dicalcium Silicate". Advances in Materials Science and Engineering 2019 (5.08.2019): 1–10. http://dx.doi.org/10.1155/2019/9856734.
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In this study, γ-dicalcium silicate (γ-C2S) was incorporated into ordinary Portland cement (OPC) to sequester CO2 to enhance the carbonation resistance of cement-based composite materials. γ-C2S can react with CO2 rapidly to form vaterite and high dense SiO2 gel which could block the pores off and then inhibit further diffusion of CO2 into the system. Cement mortar specimens containing 0%, 5%, 10%, 20%, and 40% γ-C2S as cement replacement were prepared. After water curing for 28 days followed by curing in an environmental chamber for 28 days, the specimens were then exposed to an accelerated carbonation with 5% CO2 concentration for 28 days. The carbonation depth of the cement mortar with a low replacement rate (5% and 10%) was lower than that of the OPC mortar at all ages due to the sequestration of CO2 by γ-C2S. However, the cement mortar with a high replacement rate (20% and 40%) showed less carbonation resistance due to the dilution effect of γ-C2S replacement and increase in initial porosity caused by nonhydraulic characteristic of γ-C2S.
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Gao, Ying Li, i Ling Cheng. "Study on CO2 Sequestration Property of Cement Based Composite Cementitious Materials Containing Steel Slag Used in Road". Advanced Materials Research 311-313 (sierpień 2011): 1949–52. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.1949.
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Cement based composite cementitious material containing steel slag used in road has been prepared to deal with the current situation that the transportation carbon emission increased year by year. In this material, 40% cement has been replaced by equivalent steel slag, which has the ability of CO2sequestration. This paper studied the CO2sequestration effect and the mechanical properties of the pure cement, the pure steel slag, and the cement based composite cementitious materials containing steel slag. It has been shown that the cement based composite cementitious materials containing steel slag have excellent CO2sequestration property. The mass fraction growth rate of carbon reached 10.86% after 1 hour carbonation experiment, the value between which of pure cement and pure steel slag, and the compressive strength of the composite cementitious materials at 28-day age can reach 45.3MPa, meeting the requirements of road.
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Choi, Se-Jin, Sung-Ho Bae, Jae-In Lee, Eun-Ji Bang i Haye-Min Ko. "Strength, Carbonation Resistance, and Chloride-Ion Penetrability of Cement Mortars Containing Catechol-Functionalized Chitosan Polymer". Materials 14, nr 21 (25.10.2021): 6395. http://dx.doi.org/10.3390/ma14216395.
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There have been numerous recent studies on improving the mechanical properties and durability of cement composites by mixing them with functional polymers. However, research into applying modified biopolymer such as catechol-functionalized chitosan to cement mortar or concrete is rare to the best of our knowledge. In this study, catechol-functionalized chitosan (Cat-Chit), a well-known bioinspired polymer that imitates the basic structures and functions of living organisms and biological materials in nature, was synthesized and combined with cement mortar in various proportions. The compressive strength, tensile strength, drying shrinkage, accelerated carbonation depth, and chloride-ion penetrability of these mixes were then evaluated. In the ultraviolet–visible spectra, a maximum absorption peak appeared at 280 nm, corresponding to catechol conjugation. The sample containing 7.5% Cat-Chit polymer in water (CPW) exhibited the highest compressive strength, and its 28-day compressive strength was ~20.2% higher than that of a control sample with no added polymer. The tensile strength of the samples containing 5% or more CPW was ~2.3–11.5% higher than that of the control sample. Additionally, all the Cat-Chit polymer mixtures exhibited lower carbonation depths than compared to the control sample. The total charge passing through the samples decreased as the amount of CPW increased. Thus, incorporating this polymer effectively improved the mechanical properties, carbonation resistance, and chloride-ion penetration resistance of cement mortar.
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Guo, Xiao Lu, Hui Sheng Shi, Wen Pei Hu i Kai Wu. "Durability of Calcium Sulphoaluminate (CSA) Composite Cement-Based Materials Made from Municipal Solid Waste Incineration (MSWI) Fly Ash". Applied Mechanics and Materials 719-720 (styczeń 2015): 214–17. http://dx.doi.org/10.4028/www.scientific.net/amm.719-720.214.
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Municipal solid waste incineration (MSWI) fly ash was successfully used as a main raw material in sintering and preparing calcium sulphoaluminate (CSA) cement in laboratory. This work focused on effects of cement additives of MSWI fly ash, lime powder (LI), fly ash (FA), and slag powder (SL) on the durability of CSA cement-based materials. Compared with the hardened cement containing 10% MSWI fly ash alone, compressive strengths of samples containing 20% combined additives was improved significantly. When 20% combined additives were added the resistance to shrinkage, carbonation and sulfate attack was strengthened while the combined additives had negative effects on the resistance to water permeability.
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Pan, Chang Ping, Xiang Li, Xiao Xia Lv, Sheng Jin Ge i Jian Li Shang. "Effects of High Added Quantity SSA-SSP-GSP on Resistance to Carbonation of Concrete". Applied Mechanics and Materials 670-671 (październik 2014): 333–38. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.333.
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This work is aimed at carbonation resistance of steel slag concrete based on maximum utilization of industrial waste residue. The investigation is conducted to study the carbonization resistance of concrete which containing steel slag aggregate (SSA), steel slag powder (SSP) and blast furnace slag (GSP). The ordinary concrete as baseline group, the other concrete are fabricated with the 25% SSA, in combination with 30% SSP and 20% GSP by total binder content. The microscopic properties are analyzed by XRD, SEM, micro-hardness tests etc. Experimental results indicate that the carbonation depth of concrete which adding 25% SSA, 30% SSP and 20% GSP, have lower carbonation depth significantly than the reference at 28 day and 56 day. The substitution of natural aggregate and cement are 25%, 50% respectively by industrial waste residue, that can improving microstructure of aggregate-cement stone interface, optimizing cementitious materials hydration environment, concrete presents better durability performance.
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Kim, Min Jae, Eon Sang Park, Woong Ik Hwang i Won Jung Cho. "Effect of FNS Incorporation on the Properties of Ternary Blended Cement Containing Blast Furnace Slag and Fly Ash". Advances in Materials Science and Engineering 2022 (28.05.2022): 1–9. http://dx.doi.org/10.1155/2022/1047648.
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This study aims to assess the properties of ternary blended concrete in terms of mechanical performance and resistance to chemical attack. Specimens consisted of concrete and paste having a water to binder ratio of 0.45 made with ordinary Portland cement, pozzolanic materials, and ferronickel slag. Results on compressive strength at l80 days of curing showed that ternary blended concrete with ferronickel slag was 8% to 18% higher than for OPC. For splitting tensile strength and flexural strength, however, there was no such trend. Durability was examined in terms of resistance to rapid chloride penetration, carbonation, and sulfate attack. Ternary mix showed always-higher resistance against chloride penetration and sulfate attack while being more susceptible to carbonation due to the lower pH of the cement matrix. In addition, all ternary mixes exhibited lower heat of hydration compared to OPC and binary mixes with pozzolanic materials showed the lowest heat evaporation. Furthermore, from the results of XRD analysis, identical hydration products were found irrespective to the binder, while a significant change was observed on the portlandite peak. Overall, results showed that the incorporation of ferronickel slag affected positively the properties of concrete.
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Sanjuán, Miguel Ángel, José Antonio Suárez-Navarro, Cristina Argiz, Marta Barragán, Guillermo Hernáiz, Miriam Cortecero i Pedro Lorca. "Radiological Characteristics of Carbonated Portland Cement Mortars Made with GGBFS". Materials 15, nr 9 (9.05.2022): 3395. http://dx.doi.org/10.3390/ma15093395.
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The objective of this study is to assess whether the carbonation process can modify the physicochemical characteristics of the natural radionuclides of the three natural radioactive series, together with 40K. Three mortar specimens with different percentages of ground granulated blast-furnace slag (GGBFS), cured under water for 1, 3, 7, 14, or 28 days, were subjected to a natural carbonation process. Activity concentrations for the solid and ground mortars were determined by gamma spectrometry and by radiochemical separation of isotopic uranium. The novelty of this paper relies principally on the study we have carried out, for the first time, of the radiological characteristics of carbonated Portland cement mortars. It was found that the chemical properties of the 3 mortar specimens were not affected by the carbonation process, with particular attention placed on uranium (238U, 235U, and 234U), the activity concentrations of which were equivalent to the 226Ra results and ranged from 5.5 ± 1.6 Bq kg−1 to 21.4 ± 1.2 Bq kg−1 for the 238U. The average activity concentrations for the 3 types of mortars were lower than 20.1 Bq kg−1, 14.5 Bq kg−1, and 120.2 Bq kg−1 for the 226Ra, 232Th (212Pb), and 40K, respectively. Annual effective dose rates were equivalent to the natural background of 0.024 mSv. In addition, it was observed that the variation rate for the 222Rn emanation was due primarily to the Portland cement hydration and not due to the pore size redistribution as a consequence of the carbonation process. This research will provide new insights into the potential radiological risk from carbonated cement-based materials. Moreover, the assessment that is presented in this study will convey valuable information for future research that will explore the activity concentration of building materials containing NORM materials.
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Zajac, Maciej, Jan Skocek, Jørgen Skibsted i Mohsen Ben Haha. "CO2 mineralization of demolished concrete wastes into a supplementary cementitious material – a new CCU approach for the cement industry". RILEM Technical Letters 6 (15.07.2021): 53–60. http://dx.doi.org/10.21809/rilemtechlett.2021.141.
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This contribution discusses the carbon capture and utilization (CCU) approach based on CO2 mineralization of cement paste from recycled concrete as new approach to capture CO2 and significantly contribute to the reduction in CO2 emissions associated with cement production. The current literature suggests that all CO2 released from the decomposition of limestone during clinker production can be sequestered by carbonation of the end-of-life cement paste. This carbonation can be achieved in a few hours at ambient temperature and pressure and with a relatively low CO2 concentration (< 10 %) in the gas. The carbonation of cement paste produces calcite and an amorphous alumina-silica gel, the latter being a pozzolanic material that can be utilized as a supplementary cementitious material. The pozzolanic reaction of the alumina-silica gel is very rapid as a result of its high specific surface and amorphous structure. Thus, composite cements containing carbonated cement paste are characterized by a rapid strength gain. The successful implementation of this CCU approach relies also on improved concrete recycling techniques and methods currently under development to separate out the cement paste fines and such. Full concrete recycling will further improve the circular utilization of cement and concrete by using recycled aggregates instead of natural deposits of aggregates. Although the feasibility of the process has already been demonstrated at the industrial scale, there are still several open questions related to optimum carbonation conditions and the performance of carbonated material in novel composite cements.
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Kremer, Dario, Simon Etzold, Judith Boldt, Peter Blaum, Klaus M. Hahn, Hermann Wotruba i Rainer Telle. "Geological Mapping and Characterization of Possible Primary Input Materials for the Mineral Sequestration of Carbon Dioxide in Europe". Minerals 9, nr 8 (13.08.2019): 485. http://dx.doi.org/10.3390/min9080485.
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This work investigates the possible mineral input materials for the process of mineral sequestration through the carbonation of magnesium or calcium silicates under high pressure and high temperatures in an autoclave. The choice of input materials that are covered by this study represents more than 50% of the global peridotite production. Reaction products are amorphous silica and magnesite or calcite, respectively. Potential sources of magnesium silicate containing materials in Europe have been investigated in regards to their availability and capability for the process and their harmlessness concerning asbestos content. Therefore, characterization by X-ray fluorescence (XRF), X-ray diffraction (XRD), and QEMSCAN® was performed to gather information before the selection of specific material for the mineral sequestration. The objective of the following carbonation is the storage of a maximum amount of CO2 and the utilization of products as pozzolanic material or as fillers for the cement industry, which substantially contributes to anthropogenic CO2 emissions. The characterization of the potential mineral resources for mineral sequestration in Europe with a focus on the forsterite content led to a selection of specific input materials for the carbonation tests. The mineralogical analysis of an Italian olivine sample before and after the carbonation process states the reasons for the performed evaluation. The given data serves as an example of the input material suitability of all the collected mineral samples. Additionally, the possible conversion of natural asbestos occurring in minerals as a side effect of the carbonation process is taken into consideration.
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Kim, Yoo Taek, i Jun Young Park. "Additional Aging Effect after Carbonation Process of Fly Ash Based Eco-Materials". Applied Mechanics and Materials 302 (luty 2013): 61–65. http://dx.doi.org/10.4028/www.scientific.net/amm.302.61.
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The purpose of this study is to enhance the mechanical strength of specimens containing fly ash from fluidized bed type boiler, which the recycling rate will be eventually increased. Specimens containing fly ash in a certain portion were made and aged for 3, 14, and 21 days. The carbonation process under the super critical condition was performed to enhance the mechanical property of specimens by filling the voids and cracks existing inside cement specimen with CaCO3 reactants. The additional aging effect after the supercritical carbonation process on mechanical strength of specimens was also investigated by comparing the compressive strength with and without 7 day extra aging. Carbonation under the supercritical condition and additional 7 day aging was very effective for enhancement of mechanical strength and compressive strength increased by 44%, which reached up to 88MPa.
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Skevi, Lorena, Vahiddin Alperen Baki, Yanjin Feng, Maria Valderrabano i Xinyuan Ke. "Biomass Bottom Ash as Supplementary Cementitious Material: The Effect of Mechanochemical Pre-Treatment and Mineral Carbonation". Materials 15, nr 23 (24.11.2022): 8357. http://dx.doi.org/10.3390/ma15238357.
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The need to mitigate the CO2 emissions deriving from the cement industry becomes imperative as the climate crisis advances. An effective strategy to achieve this is increasing the replacement level of cement clinkers by waste-derived supplementary cementitious materials (SCMs). In this study, the use of mechanochemically activated biomass ash for high-volume (up to 40%) substitution of cement is investigated. The effect of mineral carbonation treatment on the performance of the mechanochemically treated biomass ash as SCM was also examined. The results showed that the mechanochemically treated biomass ash was the most effective SCM, with the respective samples at 40% cement replacement reaching 63% of the strength at 28 days as compared to samples with 100% Portland cement, while only 17% of the strength was achieved in samples with 40% untreated biomass ash. As suggested by the isothermal calorimetry, XRD, FTIR, and TG analysis, the mechanochemical treatment enhanced the reactivity and the filler effect of the biomass ash, leading to improved mechanical performances of these mortars compared to those containing untreated biomass ash. Mineral carbonation reduced the reactivity of the mechanochemically treated biomass ash but still led to better strength performances in comparison to the untreated biomass ash.
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Chousidis, Nikolaos, i George Batis. "Influence of Different Waste Materials on Resistance of Cement Mortars against Carbonation and Chloride Ingress". Journal of Sustainable Architecture and Civil Engineering 29, nr 2 (27.10.2021): 216–31. http://dx.doi.org/10.5755/j01.sace.29.2.29208.
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This work is an extensive experimental study on the corrosion behavior of reinforced cementitious mortars containing industrial byproducts and waste materials. In particular, calcareous (C-class) fly ashes, iron mill scale and Electrolytic Manganese Dioxide (E.M.D.) waste were used as additives in mortars production. The abovementioned materials were used without any prior treatment or management and replaced the cement in concrete mixing by 10% wt. of cement weight. For the experimental set-up, reinforced mortars were prepared and exposed to coastal area for 12 months, while some of them were remained in a salt spray cabin for 60 days. The corrosion monitoring was performed by electrochemical and mass loss measurements, while chloride content, porosity, carbonation and mineralogy of mortars were also estimated. The results indicate, that there is a development in durability and chloride penetration resistance of composites comparing with the conventional mortars at late ages. At the same time, it was also observed that their chemical composition and fineness, control the diffusion of CO2 into the pore system and lead to increased carbonation of composite mortars. The challenge of this work is the production of eco-friendly composites with high chloride and carbon dioxide penetration resistance.
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Jeong, Sumi, Jusung Kim, Hojin Kim i Sungyu Park. "Carbonation Resistance of Mortar Mixed with Electrolysis Alkaline Aqueous Solution and Blast Furnace Slag". Applied Sciences 13, nr 2 (9.01.2023): 900. http://dx.doi.org/10.3390/app13020900.
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Cement production is the primary source of global CO2 emissions in the construction industry. Blast furnace slag (BFS) has been examined as a potential substitute for cement to reduce CO2 emissions. In addition, this substitution increases the long-term strength and improves the chemical resistance of mortar. However, a glassy film is formed on the surface of BFS while it is generated as a byproduct, lowering the initial strength of mortar. Notably, this film is destroyed in an alkaline environment. Thus, several studies have used solutions with various alkali activators. However, alkali activators are unsafe, as they are strong alkaline materials, and have low economic efficiency. This study experimentally improved the initial hydration reactivity of a mortar containing BFS as a substitute for cement, thereby improving its initial strength. We observed an increase in carbonation resistance. In addition, this study focused on evaluating the compressive strength and carbonation resistance of mortar prepared using BFS and alkaline water obtained from the electrolysis of a K2CO3 electrolyte. Results show that alkali-activated mortar using an electrolyzed alkaline aqueous solution has higher strength and contains more hydration products than that using conventional mixing water.
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Hamdany, Abdul Halim, Alfrendo Satyanaga, Dichuan Zhang, Yongmin Kim i Jong R. Kim. "Photocatalytic Cementitious Material for Eco-Efficient Construction—A Systematic Literature Review". Applied Sciences 12, nr 17 (31.08.2022): 8741. http://dx.doi.org/10.3390/app12178741.
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Photoinduced processes governed by light activated TiO2 have been studied in many ways. One of the most active areas is the development of TiO2 photocatalysis technologies on their application for reducing environmental impacts. The immobilization of TiO2 on solid support, such as cementitious materials, greatly enhances its use in practical applications. In this review, a wide range of applications for achieving eco-efficient building using cementitious composite materials containing TiO2 photocatalyst was presented. The basic mechanism of photocatalysis, such as electron excitation, charge transfer process, reactive oxygen species (ROS) generation, and its role to oxidize the pollutant and microorganisms were extensively discussed. Unlike self-cleaning and air purification systems, the study on the antibacterial function of a cement-based surface containing TiO2 is very limited. In photocatalytic cementitious materials, the key element affecting the photocatalytic performance is the accessible active surface area. However, microstructure of cementitious materials changes with age due to hydration and surface carbonation. Hence, surface area reduction and mass transfer limitation become the main drawbacks of incorporating TiO2 in cementitious materials. This review, therefore, provides the state of the art in photocatalytic cement-based composite materials and identifies the areas in which future improvement is needed.
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Park, Byoungsun, i Young Cheol Choi. "Effect of Carbonation Curing on Physical and Durability Properties of Cementitious Materials Containing AOD Slag". Applied Sciences 10, nr 19 (23.09.2020): 6646. http://dx.doi.org/10.3390/app10196646.
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In this study, the physical and durability properties of cementitious materials containing stainless steel argon-oxygen decarburization (AOD) slag were investigated by CO2 curing. Three contents (0, 30, 60%) of ordinary Portland cement (OPC) were replaced with AOD slag. Specimens were cured at four CO2 concentrations and three temperatures. The chloride diffusion coefficient, drying shrinkage, compressive strength, and porosity were measured. The drying shrinkage reduction was proportional to CO2 uptake. The chloride diffusion coefficient increased as contents of the AOD slag increased. At 15% CO2 concentration, the diffusion coefficient was similar to that of the OPC regardless of the AOD slag substitution rate. The durability of cementitious materials mixed with AOD slag can be improved by CO2 curing and can be used in construction.
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Guessoum, Meriem, Fouad Boukhelf i Fouzia Khadraoui. "Full Characterization of Self-Compacting Concrete Containing Recycled Aggregates and Limestone". Materials 16, nr 17 (26.08.2023): 5842. http://dx.doi.org/10.3390/ma16175842.
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This work deals with the study of self-compacting concretes (SCCs) containing recycled aggregates (RAs) recovered from demolition waste and limestone filler as a partial replacement for natural aggregates (NAs) and cement, respectively. Four mix designs were developed and characterized in both the fresh and hardened states. In the fresh state, the properties studied included slump, sieve stability, and t500 viscosity. In the hardened state, the properties studied were compressive strength and porosity at 15 h and 28 days, thermogravimetric analysis, and durability tests involving freeze–thaw cycles and accelerated carbonation. The results indicate the RAs lead to a decrease in slump flow. However, the substitution rate of aggregate replacement does not affect the compressive strength. This can be attributed to the optimized mix design, resulting in all SCC mixtures achieving the same compressive strength class of 30–35 MPa. As for the durability tests, the incorporation of recycled aggregates modifies the behavior of the concrete during freeze–thaw cycles. Throughout the 300 freeze–thaw cycles, all concrete mixtures exhibited a mass loss accompanied by a slight strain increase, but the materials remained visually intact. Additionally, the carbonation depth is strongly influenced by the rate of aggregate replacement due to changes in the microstructure, particularly in porosity.
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Yue, Yanfei, Jing Jing Wang, P. A. Muhammed Basheer i Yun Bai. "Establishing the Carbonation Profile with Raman Spectroscopy: Effects of Fly Ash and Ground Granulated Blast Furnace Slag". Materials 14, nr 7 (5.04.2021): 1798. http://dx.doi.org/10.3390/ma14071798.
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Establishing the carbonation profile is of great significance to the prediction of the service life of reinforced concrete structures. In our previous work, Raman spectroscopy was shown to be an efficient tool for characterizing calcium carbonate (CaCO3) polymorphs and their profile in plain Portland cement (PC) matrices. However, as supplementary cementitious materials (SCMs), particularly fly ash (FA) and ground granulated blast furnace slag (GGBS), are widely used in concrete, establishing the carbonation profile without considering the possible effects of these SCMs could be of little significance to the real world. This paper, thus, investigated the effects of FA and GGBS on the working capacity and reliability of Raman spectroscopy for establishing the carbonation profile in PC blends containing SCMs. The thermogravimetry (TG) analysis was also conducted to verify the results from Raman spectroscopy. The results show that Raman spectroscopy demonstrated a good capacity for differentiating the variation of CaCO3 contents in FA or GGBS blends. However, the incorporation of FA and GGBS into the PC system caused some adverse effects on the quantification of CaCO3 by Raman spectroscopy, which could be attributed to the darker color and weak scatter nature of FA and the high content of glassy phases in GGBS.
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Lee, Jae-In, Sung-Ho Bae, Ji-Hwan Kim i Se-Jin Choi. "Effect of Cementitious Materials on the Engineering Properties of Lightweight Aggregate Mortars Containing Recycled Water". Materials 15, nr 5 (7.03.2022): 1967. http://dx.doi.org/10.3390/ma15051967.
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With the trend toward taller and larger structures, the demand for high-strength and lightweight cement concrete has increased in the construction industry. Equipment for transporting ready-mixed concrete is frequently used to bring concrete to construction sites, and washing this equipment generates a large amount of recycled water, which is an industrial by-product. In this study, we recycled this water as the pre-wetting water for lightweight aggregate and as mixing water, and we substituted blast furnace slag powder (BS) and fly ash (FA) as cementitious materials (Cm). In addition, we evaluated the fluidity, compressive strength, tensile strength, drying shrinkage, and accelerated carbonation depth of lightweight ternary cementitious mortars (TCMs) containing artificial lightweight aggregate and recycled water. The 28-day compressive strengths of the lightweight TCM specimens with BS and FA were ~47.2–51.7 MPa, except for the specimen with 20% each of BS and FA (40.2 MPa), which was higher than that of the control specimen with 100% OPC (45.9 MPa). Meanwhile, the 28-day tensile strengths of the lightweight TCM specimens containing BS and FA were ~2.81–3.20 MPa, which are ~13.7–29.5% higher than those of the control specimen. In this study, the TCM specimen with 5% each of BS and FA performed the best in terms of the combination of compressive strength, tensile strength, and carbonation resistance.
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Kobayashi, Arato, Hiromi Fujiwara, Masanori Maruoka, Mizuki Owada i Kensuke Hayashi. "Durability of concrete with Belite-Gehlenite clinker as fine aggregate". MATEC Web of Conferences 364 (2022): 02001. http://dx.doi.org/10.1051/matecconf/202236402001.
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The Japanese cement industry uses large quantities of industrial waste and by-products as raw materials in the production of cement clinker. Although the amount of industrial waste generated annually has remained almost constant, domestic demand for cement has been falling. In order to maintain the amount of waste re-used by the cement industry, there is a need to explore new ways of utilizing clinker besides in cement production. The proportion of waste used in the production of Belite-Gehlenite clinker featured in this study is about twice as much as in normal clinker. Previous studies have shown that when clinker is used as aggregate in mortar and concrete, clinker hydration products fill cracks as they occur for added self-healing performance. In this study, in addition to the basic characteristics of concrete containing Belite-Gehlenite clinker as fine aggregate, the resistance to cracking of specimens made with the concrete is investigated. Compared with concrete using natural sand, it is confirmed that compressive strength is improved, drying shrinkage is reduced, carbonation is suppressed, and freeze-thaw resistance is maintained. It is also demonstrated that resistance to cracking is improved.
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Jain, Aman, i Rohan Majumder. "Strength, Permeability and Carbonation properties of Concrete containing Kota Stone Slurry". International Journal of Advance Research and Innovation 4, nr 4 (2016): 48–54. http://dx.doi.org/10.51976/ijari.441609.
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Concrete and stone, both are the most commonly used building materials. Rapid development in infrastructure sector has boosted the demand of both, resulting in many environmental concerns. Energy consumption and CO2 emission associated with the production of concrete and cement is a big concern. On the other side, there is a huge solid waste associated with the stone industry which has manifold environmental and financial concerns. For sustainable development, there is a need to utilize the stone waste as a partial replacement of cement (mineral admixture) in concrete so that so that the two problems simultaneously get solved. Kota stone slurry (KSS), which is abundantly available in area of Kota, Rajasthan was used as a partial replacement of the cement in this study. The objective of the present study is to determine strength and durability parameters of the concrete containing Kota stone slurry. The experimental program consists of preparing concrete mixes with two water binder ratios: 0.40 and 0.50 with varying Kota stone slurry percentage as 0, 5, 10, 15, 20 and 25% partially replaced with cement. Compressive and flexural strength test, pull-off test were performed to evaluate strength and DIN 1048 water permeability test, carbonation test and abrasion test were performed to check the durability of concrete mixes. The results indicate that with the increase in Kota stone slurry content, the compressive and flexural strength decreased. There is a marginal decrease in permeability also but the mixes containing Kota stone slurry displayed better resistance to abrasion indicating their suitability as good floor and pavement material. The properties of concrete with Kota stone slurry indicates that it can serve as an alternating material in low cost rural pavements.
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Rutkowska, Gabriela, Paweł Ogrodnik, Mariusz Żółtowski, Aleksandra Powęzka, Michał Kucharski i Martin Krejsa. "Fly Ash from the Thermal Transformation of Sewage Sludge as an Additive to Concrete Resistant to Environmental Influences in Communication Tunnels". Applied Sciences 12, nr 4 (9.02.2022): 1802. http://dx.doi.org/10.3390/app12041802.
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Concrete is an ecological material with a high potential to adapt to specific operating conditions, and the lowest carbon footprint as it is made from local raw materials—aggregate, cement, water, admixtures, and mineral additives. It is the most widely used composite material among those that are man-made and second only to water in the entire range of materials used. The aim of this research was to assess the possibility of using fly ash from the thermal treatment of sewage sludge as an alternative additive to concretes resistant to environmental influences occurring in communication tunnels. A concrete mix based on CEM I 42.5R Portland cement with various ash content of 0–20% of the cement mass was designed for the experimental work. In the course of the experimental work, the compressive strength was measured after three maturing periods, and the influence of both high temperature and the material modification on the course of carbonation were determined. The test results confirm the possibility of producing plain concrete, modified with fly ash obtained from the thermal treatment of sewage sludge. The highest average compressive strength of 43.6 MPa, 45.6 MPa, and 51.2 MPa after 28, 56 and 720 days of maturation, respectively, was for concrete containing 10% ash.
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Machner, Alisa, Maciej Zajac, Mohsen Ben Haha, Knut O. Kjellsen, Mette R. Geiker i Klaartje De Weerdt. "Stability of the hydrate phase assemblage in Portland composite cements containing dolomite and metakaolin after leaching, carbonation, and chloride exposure". Cement and Concrete Composites 89 (maj 2018): 89–106. http://dx.doi.org/10.1016/j.cemconcomp.2018.02.013.
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Choi, Se-Jin, Sung-Ho Bae, Dong-Min Ji i Sung-Hoon Kim. "Effects of Capsule Type on the Characteristics of Cement Mortars Containing Powder Compacted Capsules". Materials 15, nr 19 (29.09.2022): 6773. http://dx.doi.org/10.3390/ma15196773.
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Several studies have been reported on self-healing concrete using bacteria, admixtures, and microcapsules. Among these self-healing techniques, encapsulating cement-based materials is advantageous in that large amounts of self-healing material can be contained in a capsule and released at the cracked site for a targeted reaction. This study produced a powder compacted capsule (PCC) using the droplet and blended manufacturing methods to encapsulate cementitious materials. This study refers to the PCCs as droplet-PCC (D-PCC) and blended-PCC (B-PCC) according to the manufacturing method used. The fluidity, compressive strength, carbonation, drying shrinkage, and water permeability of cement mortar with PCCs were evaluated. The test results show that the flow of the mortar sample using D-PCC was slightly higher than that of the mortar using B-PCC. The compressive strength of the mortar sample with B-PCC was generally higher than that of the mortar sample with D-PCC. The compressive strength of the B-PCC2 sample (with 0.2% of B-PCC) was the highest at all curing ages. This may be because the B-PCC fracture load was higher than that of the D-PCC. In addition, more hydrates were observed in the B-PCC sample than in the D-PCC sample. A crack healing effect was observed in the samples with PCC, regardless of the PCC type. The effect was the greatest in the B-PCC6 sample (with 0.6% of B-PCC). The results of this study provide a reference for the PCC type and mix ratio that would yield the best mechanical properties and crack healing effect.
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Nava-Núñez, Magaly Y., Eva Jimenez-Relinque, Azael Martínez-de la Cruz i Marta Castellote. "Photocatalytic NOx Removal in Bismuth-Oxyhalide (BiOX, X = I, Cl) Cement-Based Materials Exposed to Outdoor Conditions". Catalysts 12, nr 9 (31.08.2022): 982. http://dx.doi.org/10.3390/catal12090982.
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Cement-based materials modified with 3D BiOX (X = I, Cl) microspheres at different percentages (1, 5 and 10% by weight of the cement binder) were prepared to investigate the durability of the photocatalytic NOx removal under outdoor conditions. Weathering—corresponding to a period of 13 months outdoors—was studied in terms of NO removal efficiency under visible and UVA light irradiation for BiOI and BiOCl mortars, respectively. Following this period, the samples were protected from the environment for four years, and NOx removal and selectivity to nitrates were assessed. BiOI and BiOCl mortar samples were initially photocatalytically active; NOx removal performance increased as BiOX content increased. There was good photocatalyst dispersion, and compressive strength was not significantly impacted. The BiOI mortars had nearly completely lost their activity after 5 years from casting, whereas mortars containing 10% BiOCl had maintained about 7% of initial performance. The results suggest that mortar deactivation is due to surface dirt and nitrates accumulation from NOx oxidation on the surface rather than carbonation. An internal self-deactivation mechanism that affects BiOI in mortar matrix has also been postulated.
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Cui, Yu, Min Pei, Ju Huang, Wei Hou i Zanqun Liu. "The Damage Performance of Uncarbonated Limestone Cement Pastes Partially Exposed to Na2SO4 Solution". Materials 15, nr 23 (24.11.2022): 8351. http://dx.doi.org/10.3390/ma15238351.
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Pore structure and composition of cement paste are the main two factors in controlling the sulfate attack on concrete, but the influence of carbonization on pore structure and composition is often ignored in sulfate attack. Therefore, will the damage performance of concrete partially exposed to sulfate solution be different avoiding the alterations of pore structure and composition due to carbonation? In this paper, the cement pastes were partially immersed in 5 wt. % sodium sulfate solution, with N2 as protective gas to avoid carbonation (20 ± 1°C, RH 65 ± 5%). Pore structures of cements were changed by introducing different contents of limestone powders (0 wt. %, 10 wt. %, 20 wt. %, and 30 wt. %) into cement pastes. The damage performance of the specimens was studied by 1H NMR, XRD and SEM. The results showed that the immersion zone of pure cement paste under N2 atmosphere remained intact while serious damage occurred in the evaporation zone. However, the damage of cement + limestone powders pastes appeared in the immersion zone rather than in the evaporation zone and cement pastes containing more limestone were more severely damaged. Compositional analysis suggested that the damage of the evaporation zone or the immersion zone was solely caused by chemical attack where substantial amount of gypsums and ettringites were filled in the pore volumes. Introduction of limestone powders led to the increase of the pore sizes and porosity of cement pastes, causing the damage occurred in the immersion zone not in the evaporation zone.
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Tale Ponga, Donato, Amirmohammad Sabziparvar, Patrice Cousin, Lina Boulos, Mathieu Robert i M. Reza Foruzanmehr. "Retarding Effect of Hemp Hurd Lixiviates on the Hydration of Hydraulic and CSA Cements". Materials 16, nr 16 (10.08.2023): 5561. http://dx.doi.org/10.3390/ma16165561.
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Wood wool panels are widely used in the construction industry as sustainable cementitious composites, but there is a growing need to replace traditional Portland cement with a binder that has a lower embodied carbon footprint. In addition, the sustainability of these panels may face serious impediments if the required amount of wood for their production needs a harvest rate higher than the rate at which the tree sources reach maturity. One solution is to use the wooden part of fast-growing plants such as hemp. However, the compounds extracted from the mixture of plants and water are the main cause of the delay observed during the hydration process of hydraulic binders in these cementitious composites. The objective of this study is to evaluate the effect of bio-aggregate lixiviates (hemp hurd) on the hydration kinetics of calcium sulfoaluminate (CSA) cement as a low-embodied-carbon alternative to ordinary Portland cement (OPC). The isothermal calorimeter showed that the hemp hurd lixiviate caused a greater delay in GU’s hydration process than CSA’s. At a 5% concentration, the main hydration peak for GU cement emerged after 91 h, whereas for CSA cement, it appeared much earlier, at 2.5 h. XRD and TGA analysis showed that after 12 h of hydration, hydration products such as calcium silicate hydrates (C-S-H) and portlandite (CH) were not able to form on GU cement, indicating low hydration of silicate products. Moreover, at 5% concentration, the carbonation of ettringite was observed in CSA cement. The compressive strength values obtained from the mixes containing hemp hurd lixiviate consistently showed lower values compared to the reference samples prepared with distilled water. Furthermore, the CSA samples demonstrated superior compressive strength when compared to the GU samples. After 28 days of hydration, the compressive strength values for CSA cement were 36.7%, 63.5% and 71% higher than GU cement at a concentration of 0.5%, 2% and 5% hemp hurd lixiviate, respectively.
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Ahmad, Jawad, Karolos J. Kontoleon, Ali Majdi, Muhammad Tayyab Naqash, Ahmed Farouk Deifalla, Nabil Ben Kahla, Haytham F. Isleem i Shaker M. A. Qaidi. "A Comprehensive Review on the Ground Granulated Blast Furnace Slag (GGBS) in Concrete Production". Sustainability 14, nr 14 (18.07.2022): 8783. http://dx.doi.org/10.3390/su14148783.
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In the last few decades, the concrete industry has been massively expanded with the adoption of various kinds of binding materials. As a substitute to cement and in an effort to relieve ecofriendly difficulties linked with cement creation, the utilization of industrial waste as cementitious material can sharply reduce the amount of trash disposed of in lakes and landfills. With respect to the mechanical properties, durability and thermal behavior, ground-granulated blast-furnace slag (GGBS) delineates a rational way to develop sustainable cement and concrete. Apart from environmental benefits, the replacement of cement by GGBS illustrates an adequate way to mitigate the economic impact. Although many researchers concentrate on utilizing GGBS in concrete production, knowledge is scattered, and additional research is needed to better understand relationships among a wide spectrum of key questions and to more accurately determine these preliminary findings. This work aims to shed some light on the scientific literature focusing on the use and effectiveness of GGBS as an alternative to cement. First and foremost, basic information on GGBS manufacturing and its physical, chemical and hydraulic activity and heat of hydration are thoroughly discussed. In a following step, fresh concrete properties, such as flowability and mechanical strength, are examined. Furthermore, the durability of concrete, such as density, permeability, acid resistance, carbonation depth and dry shrinkage, are also reviewed and interpreted. It can be deduced that the chemical structure of GGBS is parallel to that of cement, as it shows the creditability of being partially integrated and overall suggests an alternative to Ordinary Portland Cement (OPC). On the basis of such adjustments, the mechanical strength of concrete with GGBS has shown an increase, to a certain degree; however, the flowability of concrete has been reduced. In addition, the durability of concrete containing GGBS cement is shown to be superior. The optimum percentage of GGBS is an essential aspect of better performance. Previous studies have suggested different optimum percentages of GGBS varying from 10 to 20%, depending on the source of GGBS, concrete mix design and particle size of GGBS. Finally, the review also presents some basic process improvement tips for future generations to use GGBS in concrete.
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Mavroulidou, Maria, Blendi Feruku i Georgia Boulouki. "Properties of structural concrete with high-strength cement mixes containing waste paper sludge ash". Journal of Material Cycles and Waste Management, 26.04.2022. http://dx.doi.org/10.1007/s10163-022-01402-z.
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AbstractThis paper studies the use of wastepaper sludge ash (WPSA) for structural concrete in binary and ternary mixes with high-strength cement and two industrial by-products, ground granulated blast-furnace slag (GGBS) and pulverised fuel ash (PFA). The potential use of WPSA in this type of concrete and its combination with other supplementary cementitious materials has not been established; thus, further research is needed prior to industrial-scale applications. A series of tests investigated the soundness and setting times of the resulting cements, the fresh concrete workability, cube compressive strength at various curing times, tensile splitting strength, flexural strength, static modulus of elasticity, water absorption and carbonation of the resulting concrete. Good binary WPSA mixes were achieved with high early strength gains, but workability reduced; binary mixes with 15% WPSA, were overall the best in terms of strength and durability, whilst maintaining pumpability. An improvement in the carbonation resistance of ternary GGBS and PFA mixes was also indicated upon addition of WPSA although their strengths were lower than those of binary WPSA mixes. Further mix optimisation can lead to other robust and durable high-strength cement systems with WPSA, allowing for higher cement replacements in structural concrete, for improved environmental impact.
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Mavroulidou, Maria, Blendi Feruku i Georgia Boulouki. "Properties of structural concrete with high-strength cement mixes containing waste paper sludge ash". Journal of Material Cycles and Waste Management, 26.04.2022. http://dx.doi.org/10.1007/s10163-022-01402-z.
Pełny tekst źródłaStreszczenie:
AbstractThis paper studies the use of wastepaper sludge ash (WPSA) for structural concrete in binary and ternary mixes with high-strength cement and two industrial by-products, ground granulated blast-furnace slag (GGBS) and pulverised fuel ash (PFA). The potential use of WPSA in this type of concrete and its combination with other supplementary cementitious materials has not been established; thus, further research is needed prior to industrial-scale applications. A series of tests investigated the soundness and setting times of the resulting cements, the fresh concrete workability, cube compressive strength at various curing times, tensile splitting strength, flexural strength, static modulus of elasticity, water absorption and carbonation of the resulting concrete. Good binary WPSA mixes were achieved with high early strength gains, but workability reduced; binary mixes with 15% WPSA, were overall the best in terms of strength and durability, whilst maintaining pumpability. An improvement in the carbonation resistance of ternary GGBS and PFA mixes was also indicated upon addition of WPSA although their strengths were lower than those of binary WPSA mixes. Further mix optimisation can lead to other robust and durable high-strength cement systems with WPSA, allowing for higher cement replacements in structural concrete, for improved environmental impact.
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Karimi, Amir, Mohammad Ghanooni-Bagha, Ehsan Ramezani, Ali Akbar Shirzadi Javid i Masoud Zabihi Samani. "Influential factors on concrete carbonation-a review". Magazine of Concrete Research, 26.05.2023, 1–67. http://dx.doi.org/10.1680/jmacr.22.00252.
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After water, concrete is the most widely used substance on the planet. Cementitious materials carbonation is an inevitable process through which concrete compositions react with carbon dioxide. Carbonation leads to rebar corrosion in reinforced concrete (RC) structures which reduces the structures' longevity. This process increases cement production due to the repair and replacement which brings about more carbon dioxide emission. On the other hand, plain concrete could be one of the most potential materials in terms of CO2 storage. Therefore, understanding concrete carbonation and the influential parameters on its carbonation is significant. Identifying the effective parameters help engineers increase RC structures' carbonation resistance and increase plain concrete capacity as a carbon capture source which could be both cost-effective and environmentally friendly. In this review, an attempt has been made to summarize the present-day knowledge considering the cementitious materials' carbonation and point out the areas that need more research to be conducted. Influential factors have been categorized comprehensively, to do so. Affecting factors have been explained in three parts, containing subsets. Environmental conditions, concrete characteristics, and construction operation effects have been reviewed. Furthermore, concrete carbonation mathematical models proposed by different researchers have been examined to investigate influential parameters in the models and their precision in prediction.
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Irwan, J. M. Irwan, N. Othman i H. B. Koh. "Properties of Sand Cement Brick Containing Quarry Dust (SCBQD) and Bacteria Strain". International Journal of Sustainable Construction Engineering and Technology 11, nr 2 (2.09.2020). http://dx.doi.org/10.30880/ijscet.2020.11.02.002.
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Sand cement brick among favorable building material for low cost house construction due to its low price. Technology development in building material already explored varies waste to be added in improving properties of building materials. Beside that addition of bacteria in building material also proven in literature to improve its properties. In this research addition of bacteria in the cement sand block containing quarry dust (SCBQD) was studied. Several properties namely, compressive strength, depth of carbonation, initial rate of suction (IRS) and water absorption were studied. SCBQD is made from sand, cement, quarry dust and chipping using industrial mix design. In this study, 3% of Enterococcus faecalis (EF) and 5% of Bacillus sp (BSP) bacteria was added in the SCBQD mixes. Three SCBQD mixes were prepared including the control mix without bacteria, SCBQD with 3% EF and SCBQD with 5% BSP. Natural fine aggregate was replaced partially with the quarry dust. 100 mm SCBQD cubes were used to conduct compressive strength, depth of carbonation, initial rate of suction and water absorption test at 7, 14 and 28 days. The experimental results showed that the compressive strength value of SCBQD with addition of bacteria was increased for all curing ages. At 28 days of curing, the compressive strength value for control SCBQD containing quarry without any addition of bacteria is 3.30 MPa, while SCBQD containing quarry dust with addition of 3% of EF bacteria is 3.57 MPa and for SCBQD with 5% of BSP bacteria the value is 4.90 MPa. On the other hand, SCBQD containing 3% EF and 5% BSP gained lower IRS and carbonation depth. Depth of carbonation at 28 days was decreased 9.3% and 20% for SCBQD containing 3% EF and 5% BSP, respectively. Meanwhile, 28-day IRS was reduced 12.9% and 22.6% for SCBQD containing 3% EF and 5% BSP, respectively. In overall, the result shows that, SCBQD with 5% BSP as proven positive and better results when compared to control SCBQD and SCBQD with 3% EF bacteria which is absorb of 12.02% in water absorption. The findings showed that bio-SCBQD containing industrial waste and bacteria has good potential to be used as building material.
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Bier, Th A. "Influence of Type of Cement and Curing on Carbonation Progress and Pore Structure of Hydrated Cement Pastes". MRS Proceedings 85 (1986). http://dx.doi.org/10.1557/proc-85-123.
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ABSTRACTDifferent series of cement paste specimens were prepared with ordinary portland cement, with portland, blast furnace slag cements having slag contents of 30, 50 and 75% by mass, with commercial fly ash cement and with portland cement containing fly ash additions of 10, 20, 30 and 50% by mass. Moist curing of the specimens varied between 3 and 28 days before the pore size distribution and characteristics of the phase composition were analyzed. Subsequent to curing, the specimens were subjected to drying in air of 65% RH with a controlled CO2 content of 0, 0.03 and 2% CO2 by volume. Depth of carbonation, pore size distribution of the carbonated paste, and the phase composition were investigated after 28 days and 6 months of drying, respectively. The results show that carbonation alters the prevailing pore structure of the hydrated paste. Important parameters are the type of cement used and the duration of curing.
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MUTUNGA, Fredrick, Najya MUHAMMED, Festus NGUİ, Ismael KİNOTİ i Joseph MARANGU. "A Review on Selected Durability Parameters on Performance of Geopolymers Containing Industrial By-products, Agro- Wastes and Natural Pozzolan". Journal of Sustainable Construction Materials and Technologies, 20.11.2022. http://dx.doi.org/10.47481/jscmt.1190244.
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The applications of geopolymers as cementitious systems are becoming an alternative source of cement daily. The use of potentially suitable aluminosilicate inorganic waste materials incorporated with agro-industrial waste in the production of suitable geopolymer binders has been reported. Calcined clay and some agro-waste ash, such as coconut shells, are examples of aluminosilicate materials that exhibit strong pozzolanic activity because of their high silica-alumina composition. The pozzolanic reaction is primarily caused by the amorphous silica present in properly burned agricultural waste and clay. Based on a variety of available literature on concrete and mortar including geopolymers synthesized from agro-industrial waste, a critical review of raw materials and the mechanism of synthesis of the geopolymer has been outlined in this work. Additionally, the durability characteristics of agro-industrial waste geopolymer concrete and mortar, including resistance to chloride, corrosion, sulfate, acid attack, depth of carbonation, water absorption, thermal resistivity, Creep and drying shrinkage, are briefly reviewed.