Literatura científica selecionada sobre o tema "Recycled concrete fines"
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Artigos de revistas sobre o assunto "Recycled concrete fines"
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Naruts, Vitali, Oksana Larsen e Anton Bakhrakh. "SCC with activated recycled concrete fines". MATEC Web of Conferences 239 (2018): 01024. http://dx.doi.org/10.1051/matecconf/201823901024.
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The main application of concrete waste is its use as a coarse aggregate in concretes. Recycled concrete fines can be also used in concrete mixtures as fine aggregates or fillers. The paper describes an efficient activation method of recycled concrete fines to obtain technological, economical and ecological benefits. The idea is to combine mechanical and chemical methods of activation. According to various experiments the addition of superplasticizer into the mill speeds up grinding process. The present investigation shows that adding 0.5% by mass of recycled concrete fines allows obtaining higher specific area at the same processing time. Use of the prepared filler in SCC increases compressive strength more than 10% in compare with SCC containing limestone powder and mechanically activated recycled concrete fines.
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Iduwin, Tommy, Dicki Dian Purnama, Pratiwi Septyaning Putri e Hastanto Siswo Martono. "Pengaruh Penggunaan Material Daur Ulang Terhadap Sifat Mekanik Beton Non Pasir". FORUM MEKANIKA 9, n.º 1 (31 de maio de 2020): 11–19. http://dx.doi.org/10.33322/forummekanika.v9i1.1080.
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Infrastructure development is increasing every year making the need for concrete materials increases. Using alternative materials can reduce the scarcity of material and environmental damage caused by taking and dredging the material. This research is to find out how much influence the recycled material has on the compressive strength of no fines concrete. The variations used are recycled materials of 0%, 25%, 50%, 75% and 100%. Mechanical testing conducted is a compressive strength test to determine the compressive strength of no fines concrete at the age of 7, 14 and 28 days. The ratio of cement and aggregate used is 1: 4 with FAS 0.5. This research uses 15 x 30 cm cylindrical molds with 45 test specimens. The test results show the highest compressive strength value of non-sand concrete occurs at 0% recycled material by 10.47 Mpa and the lowest compressive strength on non-sand concrete 100% recycled material is 8.39 Mpa. The percentage of absorption of no fines concrete shows that the more recycled material is used, the smaller the value of water absorption. The highest absorption value in no fines concrete is 0% recycled material, which is 5.93% and the smallest value is in the variation of no fines concrete 100% recycled material recycled material that is equal to 4.99%.
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Soultana, Athanasia, Michael Galetakis, Anthoula Vasiliou, Konstantinos Komnitsas e Despina Vamvuka. "Utilization of Upgraded Recycled Concrete Aggregates and Recycled Concrete Fines in Cement Mortars". Recent Progress in Materials 03, n.º 03 (11 de fevereiro de 2021): 1. http://dx.doi.org/10.21926/rpm.2103035.
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Waste concrete is the most predominant constituent material among construction and demolition waste. Current waste concrete recycling is limited to the use of recycled concrete aggregates as a road-base material and less as aggregates in new concrete mixes. Further, the production of recycled concrete aggregates results in the generation of a high amount of fines, consisting mainly of cement paste particles. Hence, this study aims to produce the cement mortars using the upgraded recycled concrete aggregates (sand granulometry) for the total replacement of natural aggregates and recycled concrete fines activated through a thermal treatment method as a partial cement substitution material. Cement mortar specimens were tested for their compressive and flexural strength, density and water absorption performance. The results showed that the combined usage of upgraded recycled concrete sand for total replacement of primary crushed sand and recycled concrete fines as partial cement replacement material is a promising option to produce cement mortars.
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Dahri, S. A., B. A. Memon, M. Oad, R. Bhanbhro e I. A. Rahu. "Quality of Recycled Aggregates and Compressive Strength of No-Fines Recycled-Aggregate Concrete". Engineering, Technology & Applied Science Research 11, n.º 5 (12 de outubro de 2021): 7641–46. http://dx.doi.org/10.48084/etasr.4349.
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This research paper presents the laboratory investigations of the compressive strength of no-fines concrete made with demolished waste as coarse aggregates used in percentages from 20% to 100%. The basic properties of aggregates were determined. Sieve analysis of both conventional and recycled aggregates was conducted to ensure the existence of well-graded aggregates in concrete. Nine concrete mixes were designed with an aggregate-cement ratio of 4. Additionally, three batches were prepared (conventional, recycled, conventional no-fines concrete) and the results were compared. For all mixes, the water-cement ratio was equal to 0.5. In each batch, 5 cylinders of standard size (total 60 samples) were prepared and cured for 28 days. The weight of the specimens was determined and compressive strength was checked in a Universal Testing Machine under gradually increasing load. A decrease in weight and compressive strength was recorded for the batches of the proposed concrete. Results show that at 40% replacement level the loss of compressive strength is 19% and the weight reduction of the samples was equal to 9%.
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Bounouni, Sofiane, e Tounsia Boudina. "Durability characteristics of recycled high performance concretes under an aggressive environment (sea water)". Technium Social Sciences Journal 40 (8 de fevereiro de 2023): 578–91. http://dx.doi.org/10.47577/tssj.v40i1.8417.
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With the increase of solid construction waste (CSW) due to the acceleration of urbanization in Algeria, many ecological and environmental issues have been raised. Recycling and reuse of construction waste helps to reduce pollution, carbon emissions and preserve resources. Few studies have focused on the durability characteristics of concretes based on fine aggregates recycled from brick and concrete waste. The main purpose of this study is to formulate and analyze the performance of HPC based on waste brick and concrete fines. The substitution of alluvial sand with brick fines, causes the reduction of the heat of hydration and delays the appearance of the thermal flux peaks. while HPC rich in crushed concrete waste increases the heat of hydration. The appearance of heat flux peaks coincides for all mixtures with fines of waste concrete substitution and they will be delayed and prolonged for HPC with sand based on waste brick.
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Stuerwald, Simone, Ronny Meglin, Susanne Kytzia e Sabrina Gilg. "Use of recycled concrete fines in cement and as aggregate". Acta Polytechnica CTU Proceedings 33 (3 de março de 2022): 591–96. http://dx.doi.org/10.14311/app.2022.33.0591.
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The research project focused on investigating and optimizing the processing and use of recycled crushed sand 0/4 from concrete demolition waste, as an alternative raw material in the cement and concrete industry. Crushed sand is produced during the processing of concrete demolition waste. The goal was to identify the optimum way of using the processed material along the entire process chain so that greenhouse gas emissions, waste volumes are reduced, and natural resources are conserved. Different samples of laboratory and real crushed concrete fines were collected and examined in relation to various possible applications in accordance with the applicable standards. Results highlight, that crushed concrete fines can be used in various applications in the concrete value-chain. However, for an optimal usage, additional processing is needed.
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Mustafy, Tanvir, Md Maruf Hasan, Nayeem Ahmed Shuvo e Joarder Md Sarwar Mujib. "Characterization of Mechanical Properties of Concrete Recycled Ceramic and Glass Powder Exposed to Elevated Temperatures". MIST INTERNATIONAL JOURNAL OF SCIENCE AND TECHNOLOGY 10 (26 de junho de 2022): 01–14. http://dx.doi.org/10.47981/j.mijst.10(01)2022.350(01-14).
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Systematic reuse of industrial debris is a crucial component that helps shape the sustainable construction system and green technology. The effective optimization of waste ceramic and glass fines into concrete mixes, as partial replacements of natural sand by volume, has been used in this study to explore the mechanical properties of ceramic recycled aggregate (CRA) and glass recycled aggregate (GRA) concrete at higher temperatures. The study comprises 17 types of concrete mixtures comprised of normal concrete (NC) along with 8 different mixes from both GRA and CRA concrete. In both types of GRA and CRA concrete, the sand replacement (by volume) ratios are similar. This paper highlights NC along with the volumetric replacements of sand as 5%, 10%, 15%, 20%, 25%, 30%, 35%, and 40% in other mixes. A total of 306 cylinders were made whereas 18 cylinders for NC and each group (GRA and CRA) included n=18 cylinders. Selected temperatures were 25°C, 100°C, 200°C, 400°C, 600°C, and 800°C to determine the overall mechanical and chemical alterations in NC and recycled concrete. The study reveals that increasing the addition of recycled glass and ceramic fines improves the overall compressive strength, and tensile strength compared to normal concrete. Higher replacement of ceramic and glass fines reduces the cracks and enhances the durability of concrete. In addition, more strength reduction was noticed in NC with increasing temperatures, while the reduction rate was slower in both GRA and CRA concrete. Furthermore, the study expounds that, by exploiting the ceramic and glass wastes (as fines) into concrete would result in two-way environmental advantages. One is, it would reduce the hazardous ceramic and glass landfills while the other is, it would minimize the frequency of sand mining.
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Sharaky, Ibrahim A., Ahmed S. Elamary e Yasir M. Alharthi. "Effect of Waste Basalt Fines and Recycled Concrete Components on Mechanical, Water Absorption, and Microstructure Characteristics of Concrete". Materials 15, n.º 13 (21 de junho de 2022): 4385. http://dx.doi.org/10.3390/ma15134385.
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In this paper, the recycled fine aggregates and powders produced from crushing old basaltic concrete and natural basalt were used to produce new concrete. The sand was partially replaced by two types of recycled wastes at five percentages: 0%, 20%, 40%, 60%, and 80%. The cement was partially replaced by recycled powders and silica fume (SF) at four percentages: 0, 5%, 10%, and 20%. The concrete strengths and water absorption were obtained at several curing ages. The obtained results emphasized the positive effects of increasing the curing time on enhancing the concrete properties, regardless of the types or the waste sources. Moreover, the recycled powders retarded the hydration reaction. In addition, the recycled fine aggregates and powders could achieve about 99.5% and 99.3% of the ordinary concrete strength and enhance the tensile strength. Furthermore, the mix containing 40% of recycled fine concrete aggregate diffused the highest contents of both calcium and silicate, which led to enhancing the interfacial transition zone (ITZ) and concrete properties, compared to the other tested mixes. Finally, the water absorption of all tested concrete mixes decreased with an increase in the curing age, while the mixes integrating 10% and 20% of SF experienced the lowest values of water absorption.
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Rahu, Ahsan Ali, Bashir Ahmed Memon, Mahboob Oad, Shakeel Ahmed Dahri, Abdul Raqeeb Memon e Amjad Hussain Bhutto. "Assessment of the Flexural Strength of No-Fines Recycled Aggregate Concrete Prisms". Engineering, Technology & Applied Science Research 13, n.º 1 (5 de fevereiro de 2023): 10067–72. http://dx.doi.org/10.48084/etasr.5458.
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This study investigated experimentally the flexural strength of no-fines recycled aggregate concrete, produced using 20-70% replacement of conventional coarse aggregates with coarse aggregates from demolished waste. Six prisms in each dosage with a 1:4 mix and 0.5 water-binder ratios were prepared. A batch of prisms with conventional aggregates was also cast to compare them with the proposed concrete. An equal number of samples were cured for 7 and 28 days and tested under a gradually increasing central point load to examine failure load, central deflection, and flexural strength. The comparison of results showed an increasing trend in deflection with an increase in the dosage of recycled aggregates. The 7-day cured samples had approximately 2.6 times the deflection of conventional concrete. However, the deflection at all replacement levels remained less than that allowed by ACI-318. The results showed a decreasing trend in flexural strength with an increase in the dosage of recycled aggregates. The 40% replacement sample had a less than 20% strength reduction and is recommended as the optimum level of replacement of conventional aggregates for the production of no-fines recycled aggregate concrete.
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Zhang, Jiake, Liupeng Zhang, Boyang Xu e Jie Yuan. "Influences of Carbonated Recycled Concrete Fines on Cement Hydration". Buildings 13, n.º 4 (31 de março de 2023): 926. http://dx.doi.org/10.3390/buildings13040926.
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The preparation of recycled concrete aggregate generates a lot of fines, which are obstacles for implementing the recycled concrete aggregate. In this work, carbonation treatment is applied to improve the properties of recycled concrete fine, and the influences of carbonated recycled concrete fine (CRCF) on cement hydration process are evaluated. Both fresh and hardened properties of the cement paste samples replacing 0 to 30% of the CRCF are measured. The results reveal that the addition of CRCF obviously accelerates the hydration process of cement, especially during the early stage, and the initial and final setting times of the cement paste containing 30% CRCF are both reduced by approximately 25% compared to the control. The CRCF improves the strength gain of cement, and that influence becomes obvious with longer curing; the relative compressive strength of cement paste containing 30% CRCF is increased by 18% relative to the control after being cured for 28 days. At the same time, the early hydration of cement paste is accelerated with the addition of CRCF and the total hydration heat after 48 h of cement paste is significantly decreased with the addition of CRCF. Specifically, the total hydration heat after 48 h of cement paste with 30% CRCF is less than 50% of that with 0% CRCF. Besides that, CRCF consumes CH in cement paste and improves the pore structure of hardened cement paste. The morphology of hydrated samples shows that the shape of ettringite formed within the control sample with 0% CRCF is longer than those of the other ones formed in cement paste with CRCF, and the length decreases as the CRCF contents increase. In addition, the sample containing 30% CRCF does not show the particles, which means that CRCF reduces the ettringite forming in hardened paste samples. Thus, the findings from this work provide a better understanding of the field of waste concrete reuse.
Teses / dissertações sobre o assunto "Recycled concrete fines"
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Nguyen, Vu Nam. "Valorisation de fines et granulats issus de bétons recyclés comme matériaux cimentaires : Enhancement of fine and aggregate issued from recycled concrete as cementitious materials". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30058/document.
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La consommation de béton devient de plus en plus importante en raison d'une urbanisation accrue nécessitant la réhabilitation et la construction de bâtiments et d'infrastructures. Néanmoins, la production de béton qui doit accompagner le développement urbain entraîne des problèmes environnementaux relatifs à la préservation des ressources naturelles qui ne sont pas inépuisables. Malgré des efforts de recyclage, la plupart des matériaux recyclés sont généralement utilisés pour les travaux routiers ou de remblai. En s'inscrivant dans le Projet National Recybéton (PN), ce travail de thèse a pour objectif d'apprécier la valorisation du recyclage des matériaux issus des bétons déconstruits en les intégrant dans de nouveaux bétons. Deux types de matériaux recyclés sont étudiés, les fines qui sont produites en quantités importantes lors de la phase de concassage du béton d'ouvrage démoli, et les granulats (sable et gravillon) qui sont pour la plus grande part issus des granulats naturels initiaux. Le présent travail a donc pour mission de quantifier des propriétés des matériaux cimentaires aux différents états lors de l'utilisation de : * granulats recyclés dans le squelette granulaire, * fines de sable broyé (SBC) et de fines de dépoussiérage (FBC) en tant qu'additions minérales. La première partie est dédiée à l'étude de l'influence de l'état hydrique des granulats recyclés (sable et gravillon) sur l'évolution de la rhéologie du béton dans le temps, et à l'étude de leur incidence sur la résistance à la compression à 28 jours. Les résultats obtenus dans la limite du contexte expérimental nous permettent de suggérer des recommandations sur l'état hydrique initial des recyclés et sur leur taux d'incorporation dans le mélange de béton. La deuxième partie présente l'évaluation de la faisabilité d'utiliser des sables de bétons concassés et des fines de bétons concassés (récupérées industriellement) comme addition minérale dans les matériaux cimentaires. A partir des résultats obtenus, il est possible d'apprécier dans quelle mesure ces fines sont compatibles avec les matrices cimentaires aux états frais, durcissant et durci. La troisième partie propose une piste pour limiter le problème de la Réaction Alcali-Granulat (RAG) dans le béton de granulats recyclés. La stratégie est basée sur deux volets. La première insiste à vérifier l'applicabilité du fascicule de documentation FD P18-464 lors de l'utilisation de granulats recyclés. Le deuxième examine l'intérêt de l'utilisation des additions minérales pour limiter, voire empêcher la RAGThe concrete consumption has been becoming more and more important due to the increase of urbanization requiring the rehabilitation and the construction of buildings and infrastructure. Nevertheless, the concrete production that accompanies the urban development leads to many environmental problems related to the preservation of natural resources which are not inexhaustible. Despite of recycling efforts, most of recycled materials are typically used for road works or embankment. By participating in the French National Project Recybéton, this thesis aims to assess the enhancement of recycling materials issued from deconstructed concretes by incorporating them in new concrete design. Two types of recycled materials will be studied, the powder produced in large quantities during the crushing phase of demolished concrete, and the aggregates (sand and gravel) whose the most part issued from the initial natural aggregates. Therefore, research study aims to quantify the properties of cementitious materials in various states by the use of: • recycled aggregates in the granular skeleton, grinded recycled concrete sand and powder of dust removal as supplementary cementing materials. The first part is dedicated to the study of the influence of moisture states of recycled aggregates (sand and gravel) on the concrete's rheology evolution in time and the study of their impact on 28 days compressive strength. The results obtained within the limit of experimental context will allow suggesting recommendations on the initial moisture state of recycled aggregates and their incorporation's rate in the concrete mix. The second part presents the evaluation of the feasibility of using grinded recycled concrete sand and crushed concrete powder (industrially recovered) as supplementary cementing materials. From the results, it will be possible to assess the extent that these fines are compatible with cement matrix in the fresh state, hardening state and hardened state. The third part proposes a way to limit the problem of Alkali-Aggregate Reaction (AAR) in recycled concrete. The strategy is based on two methods. The first insists to verify the applicability of the FD P18-464 documentation when using recycled aggregates. The second examines the interest in the use of mineral additives to limit or even prevent the AAR
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Bouarroudj, Mohamed ElKarim. "Utilisation de matériaux naturels modèles pour la formulation de mortier contenant des sables et des fines de granulats recyclés". Thesis, Ecole nationale supérieure Mines-Télécom Lille Douai, 2019. http://www.theses.fr/2019MTLD0016.
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Les granulats de béton recyclé (GBR) ne sont pas suffisamment utilisés dans le secteur de la construction, principalement en raison de leur grande capacité d’absorption d’eau. Ces matériaux sont en effet composés de granulats naturels concassés et de pâte de ciment durcie adhérente qui possède une forte porosité. La première partie de ce travail de recherche s’intéresse à la valorisation des GBR de dimensions inférieures à 4 mm (sables recyclés) dans une formulation de mortier. Les comportements à l’état frais et durci de mortiers fabriqués soit avec un sable recyclé soit avec un sable naturel modèle sont comparés. Le sable naturel modèle est conçu dans le but d’obtenir des caractéristiques physiques proches de celles du sable recyclé. Cette démarche permet de mettre en évidence l’influence de la substitution d’un sable naturel par un sable recyclé de caractéristiques voisines. La seconde partie de ce travail consiste à trouver une piste de valorisation pour les particules de GBR inférieures à 125 µm. L’objectif est ici d’utiliser la poudre issue du broyage de GBR comme addition minérale. Un travail de caractérisation de la poudre recyclée permet de mettre en évidence que la fine recyclée reste poreuse après broyage. Un modèle théorique et une méthodologie expérimentale permettant d’estimer cette porosité sont développés. Enfin, des mortiers fabriqués avec un filler calcaire et une fine recyclée sont comparés, les résultats montrent que la fine recyclée peut être utilisée comme addition minéraleRecycled concrete aggregates (RCA) are not enough used in the construction sector, mainly because of their high water absorption capacity. These fine particles are composed of crushed natural aggregate and adherent hardened cement paste. The first part of this work consists in valuing particles smaller than 4 mm of an RCA in a mortar composition. Thus, the fresh and hardened behavior of mortar performed with recycled fine aggregate and model natural aggregate have been compared. The natural model fine aggregate has been performed to have an equivalent physical characteristics with the recycled one. This approach helped to understand the hardened behavior of the mortar made with recycled fine aggregate. The second part of this work consists in finding a recovery track for particles smaller than 125 μm of RCA, the goal is to use them as mineral addition. A characterization work show that the recycled powder is porous, thus a theoretical model and an experimental methodology allowing to estimate this porosity are developed. Finally, a comparison between mortar made with a limestone powder, and a recycled powder are compared. The results show that the recycled powder can be used as mineral additive in mortar composition
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Deodonne, Kunwufine. "Etudes des caractéristiques physico-chimiques de bétons de granulats recyclés et de leur impact environnemental". Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAD013/document.
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La valorisation de déchets de démolition en tant que granulats à béton présente un double objectif de préservation des ressources naturelles et de désengorgement des sites de stockage. Les granulats recyclés de béton présentent la particularité de contenir du mortier résiduel qui influence certaines de leurs propriétés et, par voie de conséquence, celles des bétons dans lesquels ils sont utilisés. Cette thèse a pour but de développer l’utilisation de bétons de granulats recyclés en remplacement total des matériaux naturels. Elle a été réalisée en partenariat industriel avec l’entreprise CHRYSO.Une étude approfondie des propriétés des granulats recyclés de béton sur plusieurs lots (plateforme industrielle et laboratoire) a conduit à l’identification puis à l’analyse des spécificités de ces matériaux comparés aux matériaux naturels. La validité des protocoles expérimentaux a été testée, et de nouveaux protocoles ont été proposés axés sur ces spécificités. Les granulats recyclés présentent une absorption plus élevée, une résistance à l’abrasion plus faible, une distribution granulaire plus étalée et une circularité moindre que les granulats naturels. La granulométrie, la proportion d’éléments fins et l’absorption d’eau des sables recyclés sont des caractéristiques dépendantes d’une part, du prélèvement des granulats recyclés et d’autre part, de la robustesse des protocoles expérimentaux. Une réactivité des éléments fins a été démontrée pour les lots issus de laboratoire, mais son influence sur les propriétés des bétons peut être considérée de second ordre lorsque les éléments fins sont constitutifs du sable. Enfin, l’absorption et la morphologie des granulats recyclés sont dépendantes de la classe granulaire étudiée. Des corrélations entre les propriétés morphologiques/géométriques et l’absorption ont été démontrées. A l’issue de l’analyse de ces propriétés, des corrections ou adaptations aux modèles prévisionnels de performances ont été proposées. La faisabilité de réalisation de bétons de granulats recyclés de béton avec remplacement total des matériaux naturels (BGRB à 100%) a ensuite été démontrée. Pour de tels matériaux, la conservation des éléments fins inférieurs à 63μm est conseillée car nécessaire à l’obtention d’un squelette granulaire correct.Afin de compenser la perte d’ouvrabilité et de résistance mécanique observée avec l’utilisation des granulats recyclés de bétons, une recherche d’adjuvant a été menée et a conduit au choix de superplastifiants de la famille des polycarboxylates. Les interprétations proposées permettent de mieux comprendre la formulation des bétons de granulats recyclés de béton et des mortiers de bétons équivalents (MBE). Ainsi, la complexité des cinétiques d’absorption et de désorption d’eau conduit à une discussion autour de la notion d’eau efficace ; la différence de morphologie des granulats recyclés implique une correction du squelette granulaire ; enfin la fragilité des granulats recyclés à l’abrasion pose la question de sa prise en compte dans la détermination du squelette granulaire optimal.Enfin, une analyse comparative des impacts environnementaux des bétons de granulats recyclés de bétons ouvre des perspectives intéressantesPromoting the use of demolition waste as recycled aggregates presents a double objective: first to preserve natural resources and secondly to relieve storage site. In regards to natural aggregates, recycled aggregates contain mortar that influences theirs properties and those of concrete in which they are used. The objective of this thesis is to develop the use of 100 % recycled aggregates in concrete. This study was realised in patnership with the company CHYRSO. Properties of recycled concrete aggregates collected from several sources were studied to identify and analyse their specificities ; results were compared to natural ones. Normalised methods were modified in order to be applied on recycled aggregates and new methods were also proposed. Recycled aggregates present higher water absorption, lower mechanical strength, spreader granular distribution and a less circular shape compared to natural aggregates. The granulometry of recycled sand, fines content and the water absorption are properties that depend on the sampling and the robustness of protocols used. A reactivity of fines obtained from materials made at the laboratory have been established, meanwhile their influence on concrete properties is considered as minor. Finally, the absorption and morphology of recycled aggregate depend on the granular fraction. Correlation between morphological and mechanical properties with water absorption have been demonstrated. After analysing these properties, correction were proposed on mechanical performance forecasting models. It was also shown that the use of fines in recycled aggregate concretes provides better mechanical properties. For such materials, keeping aggregates less than 63μm is advisable because it provides correct granular skeletton. In order to balance the loss of workability and mechanical strength observed with the use of recycled aggregates, studies were carried with several superplasticisers. Polycarboxylates were identified as appropriate superplasticisers. Interpretations facilitate understanding of concrete formulation and concrete equivalent mortar formulation made with recycled aggregates. Thus, the complexity of absorption and desorption kinectics lead to a discusion around effective water definition. The difference between the morphology of recycled aggregates and natural ones involved a correction of the granular skeletton; finally, their weakness during mechanical test modifies the granular skeletton and need to be taken into consideration.Finally, studies on environmental impacts of recycled aggregates concrete were done and compared with those of natural aggregates concrete. This study starts interesting perspectives
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Abidar, Abdellatif. "Etude des mécanismes de régénération de l'hydraulicité de bétons recyclés dans le cadre d'une approche économie circulaire". Electronic Thesis or Diss., Université Gustave Eiffel, 2024. http://www.theses.fr/2024UEFL2039.
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Le béton, largement utilisé dans la construction, est essentiel à la société moderne. Cependant, lorsque les bâtiments arrivent en fin de vie, la démolition devient inévitable, contribuant ainsi à l'accumulation annuelle des débris de béton. Cette situation pose un défi majeur en matière de gestion des déchets de construction. Face à cette réalité, le recyclage du béton émerge comme une nécessité. Cette approche permet non seulement de réduire la quantité de déchets envoyés en décharge, mais aussi de préserver les ressources naturelles, favorisant une construction plus durable. Cette thèse s'inscrit dans le cadre d'un projet de recherche centré sur le recyclage du béton dans une perspective d'économie circulaire. Elle propose une étude approfondie de la régénération des propriétés hydrauliques des matériaux cimentaires, avec pour objectif de comprendre les mécanismes impliqués à cette régénération. Cette analyse se déroule en trois étapes distinctes. Tout d'abord, nous avons examiné une phase pure de C3S, suivi par une phase intermédiaire utilisant du ciment Portland, pour finalement conclure avec une étude sur les bétons recyclés issus de retours et de déconstructions.Nous proposons un processus basé sur le traitement thermique des poudres issues du concassage des matériaux cimentaires, effectué à des températures basses allant de 400 °C à 800 °C. Des techniques de caractérisation comme l’ATG, l’IRTF, le RMN 29Si et la DRX avec la méthode Rietveld (TOPAS V6), ont été utilisées pour comprendre les mécanismes de régénération de l'hydraulicité.Les traitements thermiques appliqués aux différentes phases à partir de 600 °C ont révélé la formation de bélite. Plus précisément, le polymorphe β-C2S s'est formé dans le cas de la phase pure, tandis que les polymorphes α'-C2S et β-C2S se sont formés dans le cas de la pâte de ciment Portland. Les traitements thermiques appliqués sur les bétons de retour et de déconstruction ont révélé des mécanismes similaires, avec la formation de bélite observée à partir de 700 °C. Ces découvertes ont été confirmées par la diffraction des rayons X (DRX) et la spectroscopie RMN 29Si, cette dernière ayant également montré que les C-S-H sont complètement décomposés à cette température, conduisant à la formation de bélite.Les phases régénérées montrent une réactivité élevée, probablement en raison de la forte réactivité de la chaux produite pendant les traitements thermiques. Par conséquent, presque toute la bélite formée a été consommée après 28 jours d'hydratation. Les liants obtenus à des températures comprises entre 600 et 800 °C ont conduit à la reformation d'hydrates tels que les C-S-H, la Portlandite et l’Ettringite.Les mortiers fabriqués avec 100 % de liants issus des traitements thermiques appliqués aux pâtes de ciment ont dépassé 16 MPa en compression après 90 jours et peuvent atteindre plus de 30 MPa lorsqu’ils sont remplacés à 40 % par du CEM I, malgré leur forte demande en eau. En revanche, les mortiers composés de 100 % de liants issus de béton ne dépassent pas 4 MPa en compression après 90 jours, mais peuvent atteindre plus de 20 MPa en compression et 5 MPa en flexion lorsqu’ils sont remplacés à 40 % par du CEM IConcrete, widely used in construction, is essential to modern society. However, as buildings reach the end of their life cycle, demolition becomes inevitable, contributing to the annual accumulation of concrete debris. This situation presents a major challenge in construction waste management. Faced with this reality, concrete recycling emerges as a necessity. This approach not only reduces the amount of waste sent to landfills but also preserves natural resources, promoting sustainable construction.This thesis is part of a research project focused on concrete recycling from a circular economy perspective. It offers an in-depth study of the regeneration of hydraulic properties of cementitious materials, aiming to understand the underlying mechanisms of this regeneration. This analysis is performed in three distinct stages. Initially, we examined a pure phase of C3S, followed by an intermediate phase using Portland cement, concluding with a study on recycled concretes from returns and demolitions.We propose a process based on the thermal treatment of powders derived from crushing cementitious materials, conducted at low temperatures ranging from 400°C to 800°C. To understand the mechanisms of hydraulicity regeneration, characterization techniques such as TGA, FTIR, 29Si-NMR, and XRD with the Rietveld method (TOPAS V6) were employed.Thermal treatments applied to various phases from 600°C revealed the formation of belite. Specifically, the β-C2S polymorph formed in the case of the pure phase, while the α'-C2S and β-C2S polymorphs formed in the case of Portland cement paste. Thermal treatments applied to returns and demolition concretes revealed similar mechanisms, with belite formation observed from 700°C onwards. These findings were confirmed by X-ray diffraction (XRD) and 29Si-NMR spectroscopy, the latter also showing complete decomposition of C-S-H at 600°C, leading to belite formation. The regenerated phases exhibit high reactivity, likely due to the strong reactivity of lime produced during thermal treatments. Consequently, almost all formed belite was consumed after 28 days of hydration. Binders obtained at temperatures between 600 and 800°C led to the reformation of hydrates such as C-S-H, Portlandite, and Ettringite.Mortars made with 100% binders from thermal treatments applied to cement pastes exceeded 16 MPa in compression after 90 days and could reach over 30 MPa when replaced by 40% CEM I, despite their high water demand. Conversely, mortars composed of 100% binders from concrete do not exceed 4 MPa in compression after 90 days but can reach over 20 MPa in compression and 5 MPa in flexion when replaced by 40% CEM I
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De, Freitas Macedo Hian. "Concrete Made with Fine Recycled Concrete Aggregate (FRCA): A Feasibility Study". Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39619.
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In the process of crushing concrete waste, significant amounts of fine by-products, the so called fine recycled concrete aggregates (FRCA), are generated and excluded from potential use. Limited research has thoroughly investigated the performance of concrete mixes with FRCA, very likely due to the complexity in analysing non-negligible amounts of adhered residual cement paste (RCP). Although some studies have proposed promising sustainable mix-design procedures accounting for the different microstructure when using coarse recycled concrete aggregates (CRCA), no similar approach exists for FRCA concrete. In this work, two promising procedures for mix-designing eco-efficient concrete with 100% FRCA are proposed accounting for the presence of RCP to reduce cement content in new mixtures. First, built on top of the existing procedure for CRCA mix-design, modifications to the Equivalent Volume (EV) method were introduced toconsider full replacement of fine natural sand by FRCA. Second, based on the concept of continuous Particle Packing Models (PPM), an optimized procedure was proposed to allow maximum packing density of FRCA mix linked to a given level of measured RCP content. Results verified the feasibility of producing eco-efficient concrete mixes with 100% FRCA, emphasizing the PPM mixes to report superior rheological and mechanical performance along with suitable durability-related properties. Yet, results also indicated the influence of simple or multistage crushed FRCA on the overall performance of mixes.
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Mendes, Everton Luiz da Silva. "Caracterização e composição de agregados reciclados para obtenção de concreto autoadensável leve reciclado com fins estruturais". Universidade Federal de Alagoas, 2016. http://www.repositorio.ufal.br/handle/riufal/1706.
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The use of recycled aggregate in the production of self-compactig concrete (SCC) is relatively recent. Few studies have been developed, but, there are numerous advantages in its application. The recycled lightweight self-compacting concrete (RLSCC) offers several advantages of SCC, due to the self-compacting properties, it absorbs construction residues, in the use as recycled aggregates, and the lightness due to the smaller specific mass of the recycled aggregates, it promotes the reduction of the loads due to the own weight . However, studies carried out in concrete with recycled aggregates (RA) have shown to be very complex due to the characteristics of these aggregates, such as: high porosity, high water absorption, irregular shape, rough surface, etc. These characteristics tend to lead to mixtures with less workable and lower mechanical strength. In this way, the study had as objective to obtaining the RLSCC, separate the process in two steps: aggregates and mortar. Where, the characterization of the RA is the way to understand its characteristics and the limitations that it will impose in the mixture of concrete. The study of mortars, to verify a composition with the best parameters of fluidity and rheological, since the difficulty faced by researchers in obtaining workable mixtures. Thus, it was verified that the standardized characterization methodologies, for natural aggregates, face some difficulties in their application in recycled aggregates, rendering them inefficient. The characteristics of the recycled aggregate could be attenuated with a composition study, reaching very workable mortars, with low yield stress and moderate viscosity. The SCC was obtained through a study of maximum content of recycled coarse aggregate, through concrete tests. The obtained concrete presented compression strength of 30 MPa and apparent specific mass of 2000 kg/m³, classifying it as concrete of structural application and light.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
A utilização de agregado reciclado na produção de concreto autoadensável (CAA) é relativamente recente. Poucos estudos têm sido desenvolvidos, mas, observam-se inúmeras vantagens em sua aplicação. O concreto autoadensável leve reciclado (CAALR) oferece diversas vantagens do CAA, devido às propriedades de autoadensabilidade, absorve resíduos de construções, na utilização como agregados reciclados, e a leveza devido a menor massa específica dos agregados reciclados, promove a redução das cargas devido ao peso próprio. No entanto, estudos realizados em concreto com agregados reciclados (AGR), têm se mostrado muito complexos devido às características destes agregados, como: elevada porosidade, alto teor de absorção de água, forma irregular, superfície rugosa, etc. Características estas que tendem a conduzir a misturas pouco trabalháveis e de resistência mecânica inferior. Desta forma, o estudo teve como objetivo a obtenção CAALR, separando o processo em duas etapas: agregados e argamassa. Onde, a caracterização do AGR é o meio para o entendimento de suas características e das limitações que ele irá impor na mistura de concreto. Já o estudo de argamassa, o objetivo foi verificar uma composição com os melhores parâmetros de fluidez e reológicos, visto as dificuldades enfrentadas por pesquisadores em obter-se misturas trabalháveis. Assim, verificou-se que as metodologias de caracterização normatizadas, para agregados naturais, enfrentam algumas dificuldades na sua aplicação em agregados reciclados, tornando-as pouco eficientes. As características do agregado reciclado miúdo puderam ser atenuadas com um estudo de composição, chegando a argamassas muito trabalháveis, com baixa tensão de escoamento e viscosidade moderada. A obtenção do CAA foi possível, através de um estudo de teor máximo de agregado reciclado graúdo, através de ensaios em concreto. O concreto obtido apresentou resistência de 30 MPa e massa específica aparente de 2000 kg/m³, classificando-o como concreto de aplicação estrutural e leve.
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Rostirola, Ângelo Cezar Fumagalli. "Estudos exploratórios da produção de concreto celular autoclavado com o emprego de finos oriundos da reciclagem de concreto como agregados". Universidade do Vale do Rio dos Sinos, 2013. http://www.repositorio.jesuita.org.br/handle/UNISINOS/3728.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
SINDUSCON-NH - Sindicato das Indústrias da Construção Civil Novo Hamburgo
A construção civil atualmente é a indústria com maior crescimento no Brasil, fomentada por financiamentos e programas do governo federal. É também uma das indústrias que mais consome recursos naturais e energia, além de ser a principal geradora de resíduos sólidos urbanos. Grande parcela destes recursos naturais consumidos pela construção é formada pelos agregados. Uma alternativa econômica e ambientalmente correta, para diminuir a extração deste material, é a sua substituição por algum outro material, se possível por um resíduo, como apontam várias pesquisas. A busca por materiais e produtos ecologicamente corretos está em uma crescente, assim como os estudos para a reciclagem de diversos resíduos. A união entre produtos que consomem um volume menor de matéria-prima com o emprego de resíduos na sua produção parece uma saída viável para um desenvolvimento mais sustentável. Artefatos para a construção civil produzidos com concreto celular autoclavado (CCA) utilizam até quatro vezes menos materiais quando comparados a produtos com características semelhantes, produzidos com concreto convencional, cerâmico, entre outros. Além do menor consumo dos materiais constituintes, o concreto celular possui outras propriedades interessantes, como: suficiente resistência à compressão; isolamento térmico e acústico; baixa densidade; resistência ao fogo. Esta pesquisa teve como objetivo principal avaliar a influência da substituição parcial do agregado natural por agregado reciclado de concreto (ARC) na produção de concreto celular autoclavado. Após realização de estudos-piloto, optou-se pelo emprego da proporção de Cimento e Agregado Natural (AN) de 67% e 33% e sobre estes 0,45% de Cal e 0,3% de Alumínio com relação água/sólidos igual a 0,32. Foram empregados Cimento Portland CP-V ARI, Cal calcítica, areia natural e agregado fino reciclado de concreto, em teores de 0%, 25% e 50%. A dimensão máxima do agregado empregado na produção de CCA é de 150 µm. A cura foi realizada em autoclave após um tempo de espera de 24 horas a partir do início da mistura, por um período de 6 horas. Foram avaliadas a resistência à compressão, a absorção de água capilar, a massa específica e a porosidade. Os ensaios de resistência à compressão foram realizados em 48 e 72 horas, e a absorção de água, em corpos de prova preparados e acompanhados pelo período de 96 horas. A microestrutura dos CCA produzidos foi caracterizada por microscopia eletrônica de varredura (MEV). Verificou-se que existem expressivas alterações nas propriedades do CCA produzidos com ARC em substituição do AN, com a tendência de aumentar a densidade de massa aparente, bem com a resistência à compressão, a medida que aumenta-se o teor de ARC. Na análise dos resultados, percebeu-se que o uso de ARC alterou as propriedades dos concretos produzidos neste estudo exploratório, sem, entretanto, inviabilizar o seu emprego. Com um ajuste da dosagem, pode ser obtido um CCA produzido com ARC, cujo comportamento seja compatível com o comportamento de CCA produzido somente com o AN.
In the last years, the Brazilian construction industry is among those of national production sectors that have been having a great growing, mostly due to the incentive from the government and due to financed resources by private and public agents. This industry is also one of the major consumers of natural resources and energy, besides being the main generator of solid waste. One of these natural resources used in the constructions is sand. An environmentally friendly and economical alternative to reduce the extraction of natural resources is the use of recycled waste. The associated use of low volume of raw materials with alternative materials, like waste, is one of the ways to get more sustainability in the construction sector. Construction and building components made with autoclaved cellular concrete (ACC) employ four times less material than others with the same function. Other advantage of ACC is the performance of its properties like compressive strength, thermal and acoustic behavior, lower density, fire resistance. The aim of this research was to investigate the use of fine grains from recycled concrete aggregate (ARC) as partial sand replacement in the production of autoclaved aerated concrete. With the goal to find the mix proportion some pilot studies were made. After this, it was chosen a relation of 67% of cement and 33% of natural fine aggregate (sand). The lime was used in the amount of 0.45% of total cement and sand, and 0.3% of aluminium. The water to total solids ratio was 0.32. It was employed Portland cement type V according to Brazilian standards, calcitic lime, natural sand and ARC passing in sieve with 150 micron opening. The replacement rate of sand by ARC was 0%, 25% and 50%. From 24 hours after the mixing of materials, the samples were submitted to steam curing in an autoclave chamber for 6 hours. It was evaluated the compressive strength, the density, the capillary water absorption and porosity. The compression strength tests were performed at 48 and 72 hours. Water absorption tests were conducted for 96 hours after samples preparing. The capillary porosity was calculated with the capillary water absorption data. ACC's microstructure analysis was done by scanning electron microscopy (SEM). The results showed in general that the behavior of ACC produced with ARC differs significantly from the ACC produced with natural aggregate. When the ARC rate increases the apparent specific gravity also increases as well as the compressive strength. The observed increase in the apparent specific gravity is not desired. However this behavior of ACC done with RCA does not prevent the use of this recycled aggregate. An optimized study of pre-wetting of RCA could improve its performance as aggregate for use in ACC, once its grain size showed to be appropriated for this kind of use.
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Yerramala, Amarnath. "Development and characteristics of foamed concrete containing fine recycled and secondary aggregate". Thesis, University of Dundee, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500568.
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Adessina, Ayodele. "Caractérisation expérimentale et modélisation multi-échelle des propriétés mécaniques et de durabilité des bétons à base de granulats recyclés". Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1100/document.
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Ce travail de thèse combine des approches expérimentales et théoriques visant à caractériser les propriétés mécaniques et de durabilité des bétons à base de granulats recyclés. La première partie est consacrée à la quantification de l'effet des granulats recyclés sur les propriétés mécaniques et de durabilité de ces bétons. Les résultats montrent que les propriétés mécaniques et de durabilité des bétons à base de granulats recyclés sont sensibles non seulement aux propriétés physiques des granulats recyclés mais aussi à leur quantité au sein de la microstructure. Par ailleurs, une caractérisation des propriétés mécaniques locales grâce aux essais de nano indentation et micro indentation a aussi été entreprise; ce qui a permis d'avoir accès aux propriétés mécaniques des phases telles que les zones d'interface ou encore l'ancien mortier. La deuxième partie est une approche consacrée à l'établissement des modèles multi-échelles en mesure de rendre compte des propriétés macroscopiques (mécanique et de diffusion) des bétons à base de granulats de démolition en tirant profit des informations recueillies sur la microstructure (observation au microscope, nano et micro indentation,...). Une prise en compte du caractère complexe des granulats recyclés a aussi été abordée dans ce développement théorique. Enfin, une comparaison des résultats des modèles avec ceux expérimentaux est présentée puis discutée dans ce travailThis thesis combines experimental and theoretical approaches to characterize the mechanical and durability properties of recycled aggregate concretes (RAC). The first part of the work is devoted to the quantification of the impact of recycled concrete aggregates on the mechanical and durability properties of RAC. The results show that mechanical and durability properties of recycled aggregate concretes depend not only on the physical properties of recycled concrete aggregates but also on their quantity in the microstructure. Furthermore, statistical indentation technique is used to capture the local mechanical properties of phases in the microstructure of RAC such as the interfacial transition zones and the attached mortar. The second part of this study deals with the multi-scale modeling of the mechanical and the durability properties of RAC. The main purpose of this theoretical work is to establish models capable to predict the macroscopic behaviour based on the available information on the microstructure (obtained by optical microscopy or through indentation technique). The established models take into account the complex structure of the recycled concrete aggregates. Finally, the results of the models are compared with experimental data for discussion
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Nagaraju, Yathiraj. "Contribution to the Understanding of the Rheological Behaviour of Recycled Concrete Aggregate Mixtures Made of Coarse and Fine Particles". Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40684.
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The use of recycled concrete aggregates (RCA) has gained increased attention in the past few decades as an alternative to decrease the carbon footprint of concrete construction. Yet, most of the research performed so far demonstrates that RCA concrete displays inferior performance in the fresh and hardened states when compared to conventional concrete (CC). The latter is believed due to the fact that very often the different microstructure of RCA is not accounted for while the mix-proportioning of RCA concrete.
Recently, a number of mix-design procedures accounting for RCA microstructure have been proposed. Amongst them, the Equivalent Volume (EV) method seems to be quite promising. The EV method may proportion RCA concrete made of coarse (CRCA) or fine (FRCA) RCA and is based on a companion CC. Previous research has demonstrated that the fresh and hardened properties of EV mix-designed CRCA are suitable for structural applications. Yet, very few research, analysis and quantification have been conducted on the fresh behaviour of EV mix- proportioned FRCA concrete. This work presents a comprehensive study on the rheological behaviour of EV mix-designed CRCA and FRCA concrete presenting distinct features (i.e. inner qualities, mineralogy, fabrication process, etc.) through the use of a planetary rheometer (IBB). Results show that the EV is capable of proportioning low embodied energy CRCA and FRCA concrete with shear thinning profiles. The latter suggests that these mixtures are suitable for applications under high torque regimes such as vibrated or pumped concrete.
Capítulos de livros sobre o assunto "Recycled concrete fines"
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Kulisch, D. "The Effect of Grinding Process on Recycled Cement Paste Fines". In Concrete Durability and Service Life Planning, 18–22. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-43332-1_4.
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Kalinowska-Wichrowska, Katarzyna, Edyta Pawluczuk, Marta Kosior-Kazberuk, Filip Chyliński, Alejandra Vidales Barriguete e Carolina Pina Ramirez. "Geopolymer Composites with Recycled Binders". In Springer Proceedings in Materials, 212–19. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-72955-3_21.
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AbstractThe application of geopolymers as an alternative to cement concretes is becoming increasingly important. The significant advantage of this composites is that, the basic ingredient is not a cement, but pozzolans such as waste materials—fly ash, fly ash slag mix, red ceramic fines, recycling cement mortar—which makes building materials more environmentally friendly. Currently the availability of blast furnace slag and high-quality fly ash is limited in Europe. At the same time, the ways for management of the concrete rubble and the construction waste are being sought, because the volume of waste materials is constantly increasing.Therefore, the application of secondary binders extracted from the recycling of various construction waste (recycled cement mortar, red ceramic fines, fly ash-slag mix) in geopolymers was proposed. The recycled binders were introduced into geopolymer composites as a replacement of 25% by mass of primary binder (fly ash) and the 65, 75 and 85ºC was the curing temperature. The process of manufacturing the recycled binders has been described and basic parameters of new binders. The tests of physical and mechanical properties of the composites such as compressive strength, flexural strength, volume density in dry state and saturated one and water absorption were performed. The microstructure of geopolymers was examined using scanning electron microscopy (SEM). The results obtained show that recycled binders obtained from the treatment of construction waste could be a valuable component of geopolymers.
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Kono, T., S. Nishiie e M. Sugimoto. "Study on carbon-neutral ground improvement using recycled concrete fines". In Geotechnical Engineering Challenges to Meet Current and Emerging Needs of Society, 3038–41. London: CRC Press, 2024. http://dx.doi.org/10.1201/9781003431749-595.
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Liu, Jingwen, Caitlin Lommaert, Pieter Rauwoens e Özlem Cizer. "Early Hydration of Slag Cements Blended with Recycled Concrete Fines". In RILEM Bookseries, 394–402. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-70277-8_45.
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Wang, Chen, Yue Chen, Jianfeng Xue e Yuekai Xie. "Mechanical and Dynamic Behaviour of Natural and Recycled Concrete Aggregates Containing Different Percentages of Fines". In Lecture Notes in Civil Engineering, 313–19. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-8229-1_33.
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Lee, Kevin Jia, e Sook Fun Wong. "Recycled Mixed Plastic Fine Aggregate in Cement Concrete". In Springer Proceedings in Materials, 111–18. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-72955-3_9.
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AbstractThe literature extensively examines the utilization of sorted single-type plastic waste from post-consumer waste streams as a sustainable substitute for natural sand in cement concrete. However, severe heterogeneity of plastic waste in municipal solid waste streams, including variations in polymer types, grades, shapes, sizes, and cross-contamination with other commingled waste materials, poses a significant challenge in adopting findings from prior research that necessitates high-purity single-type plastic waste for concrete applications. This paper reports the characterization of cement concrete incorporated with mixed plastic fine aggregate (rMPFA) containing an optimized blend of plastic types produced using a proprietary mixed plastic recycling process. Five concrete mixtures containing 0% (M0), 10% (M10), 20% (M20), 30% (M30), and 40% (M40) rMPFA by volume of natural sand were investigated in this study. The laboratory results show that concrete mixture M20 had comparable compressive strength and water penetration test results when compared to control mixture M0. Additionally, toxicity characterization of concrete mixture M20 demonstrated a reduction of heavy metals in the leachate solution when compared to control mixture M0. Furthermore, microplastic detection analysis results of concrete mixtures M0 and M20 were comparable and stable.
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Hansen, Torben C., e Marius Marga. "Strength of Recycled Concrete Made from Coarse and Fine Recycled Concrete Aggregates". In Demolition Reuse Conc Mason V2, 605–12. London: CRC Press, 2023. http://dx.doi.org/10.1201/9781003416562-13.
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Nebiyu, Wallelign Mulugeta, Denamo Addissie Nuramo e Abel Fantahun Ketema. "Experimental Study of Recycled Aggregate Concrete Produced from Recycled Fine Aggregate". In Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 49–67. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-93712-6_4.
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Soni, Nancy, e Dharmendra Kumar Shukla. "Study on Concrete Developed with Recycled Fine Aggregate". In Lecture Notes in Civil Engineering, 77–94. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-6557-8_7.
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Pedersen, L. G., e L. M. Ottosen. "Fine Recycled Concrete Aggregates Particle Morphological Parameters and Packing Properties". In Concrete Durability and Service Life Planning, 33–36. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-43332-1_7.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Recycled concrete fines"
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Feng, Jun, Kai Zhang e Jie Zhang. "Study on the Influence of Fine Aggregate Replacement Rate and Age on the Mechanical Properties of Recycled Concrete". In Conference Proceedings of The 12th International Symposium on Project Management, China, 790–95. Riverwood, NSW, Australia: Aussino Academic Publishing House (AAPH), 2024. http://dx.doi.org/10.52202/076061-0105.
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Reiners, Jochen, Jan Höffgen, Maureen Denu, Christoph Müller e Frank Dehn. "Der Einfluss von Recyclingmaterial auf die Eigenschaften von Beton". In Bauen mit rezyklierten mineralischen Baustoffen - Von der Ausnahme zur Regelbauweise : 20. Symposium Baustoffe und Bauwerkserhaltung. KIT Scientific Publishing, 2024. http://dx.doi.org/10.58895/ksp/1000167485-6.
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In recent years, the increasing scarcity of resources, particularly in the area of aggregates in the construction industry, as well as the recognition of the need for a circular economy in concrete construction, has led to a greater focus on the use of recycled materials. Recycled concrete aggregates in particular are increasingly being used. However, as these can have an impact on the properties of fresh and hardened concrete, it is important to analyse their influence. This article therefore deals with the production, mechanical behaviour, durability properties and fire behaviour of concretes containing recycled aggregates. In addition, accompanying scientific programmes such as an AiF joint research project at the VDZ/KIT are presented. As a positive environmental impact is the goal when using recycled materials, the life cycle assessment of concrete with recycled aggregates is highlighted in this article. As cement in particular is decisive for the environmental impacts of concrete, the approach of using recycled concrete fines as a cement main constituent is also addressed.
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"The Stabalization of Aqueous Heavy Metal Species Using Recycled Concrete Fines". In SP-202: Third Canmet/ACI International Symposium: Sustainable Development of Cement and Concrete. American Concrete Institute, 2001. http://dx.doi.org/10.14359/10783.
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Klink, Tyler S., William J. Likos e Bu Wang. "Particle Breakage and Fines Generation of Recycled Concrete Aggregates Subjected to Compaction". In Geo-Congress 2020. Reston, VA: American Society of Civil Engineers, 2020. http://dx.doi.org/10.1061/9780784482827.014.
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"A Systematic Study on Physical and Mechanical Properties of No-Fine Concrete with Additives". In Recent Advancements in Geotechnical Engineering. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901618-24.
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Abstract. No-fine concrete (also called as pervious concrete or porous concrete) is a lightweight concrete made up of primary binder and coarse aggregates with little or no sand. Due to the reduced amount or absence of fines, it produces large number of voids which improves permeability to greater extent. Hence this type of concrete can be used in pavements and in parking lots. The literature review is carried out to study the physical and mechanical properties of no-fine concrete with additives. Various reports were collected and studied about variation in physical and mechanical properties of pervious concrete with different additives. Additives may be either mineral additives (fly ash, silica fumes, rice husk ash etc..,) or chemical additives (plasticizers, super plasticizers, retarders etc..,). Our project involved the utilization of recycled coarse aggregates, fly ash and rice husk in no-fine concrete. After this study, it was concluded that ‘upon the addition of additives, it increases permeability by decreasing its strength and vice-versa’. Balancing its permeability and strength remains challenging.
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Herath, H. M. V. K., e A. S. M. Mendis. "INVESTIGATION MECHANICAL & DURABILITY PROPERTIES OF CRUMBED RUBBER CONCRETE CONTAINING RECYCLED CONCRETE AGGREGATE". In The SLIIT International Conference on Engineering and Technology 2022. Faculty of Engineering, SLIIT, 2022. http://dx.doi.org/10.54389/rske7223.
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The concrete construction industry requires huge amount of natural resources. Currently natural resources are depleting while demand for concrete is increasing. Several studies are focused to solve this issue. The waste rubber has become a huge environmental issue worldwide. Researchers identified a sustainable way of reusing waste rubber by recycling it to Crumbed Rubber and partially replacing that for fine aggregate in concrete. However, with introduction of this crumbed rubber to concrete, the compressive strength of developed concrete was decreased. Therefore, the main aim of this research is to improve compressive strength in Crumbed Rubber Concrete using recycle concrete aggregate. Other than that, some fresh properties, mechanical & durability properties were investigated. 15 percent of replacement of fine aggregate by rubber has been identified as an optimum replacement level by other studies. Therefore, this study was conducted for 15% volume based fine aggregate replacement. As recycle aggregate act as a cementitious binder, it was added in 10,15,20,30 percent of weight basis for cement. The w/c ratio was kept constant at 0.57. Maximum 10 mm aggregate was used in the study. The crumbed rubber replacement resulted in 60 percent decrement in compressive strength and recycled aggregate in all levels resulted in a higher compressive strength than rubber-only concrete but got optimum increment in 20 percent and starts to decrease. Same as compressive strength, splitting tensile, flexural strength increased to optimum values with 20 percent of recycled aggregate. The available design codes were used to calculate theoretical values using experimental values to investigate adequacy of these mixes. The investigate revealed that available standard guidelines cannot be used to predict the behavior of crumbed rubber concrete containing recycled concrete aggregate. This study proves that addition of recycle aggregate to crumbed rubber concrete improves its strength. However, the durability and dynamic properties of this developed concrete needs to be investigated. KEYWORDS: crumbed rubber concrete, recycled concrete aggregate, mechanical properties
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Bosold, Diethelm. "Rezykliertes Material: Die Integration von R-Beton in den neuen Regelwerken". In Bauen mit rezyklierten mineralischen Baustoffen - Von der Ausnahme zur Regelbauweise : 20. Symposium Baustoffe und Bauwerkserhaltung. KIT Scientific Publishing, 2024. http://dx.doi.org/10.58895/ksp/1000167485-1.
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The German Committee for Reinforced Concrete's guideline on concrete with recycled aggregates has regulated the use of recycled concrete for many years. With increasing discussion on the topics of sustainability and resource efficiency, the demand for recycled aggregates is growing. This development has been taken into account with the adoption and continuation of the regulations of the DAfStb guideline in the revised DIN 1045. This topic also plays a role in other areas such as cement production. In future, the fine components of recycled aggregates can also be used as a further main component of cement. In addition to the sometimes restrictive specifications of the regulations, innovative ideas can of course always be realised via approvals, for example concrete components that contain exclusively recycled aggregates.
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Abdulkarem, Mais A., Dalia Adil Rasool e Baydaa Jabber Nabhan. "Exploring Sustainable Building Practices: Utilizing Olive Stone Waste and Crushed Glass in Concrete Mixtures". In The 2nd International Conference on The Future Sustainable Energy. Switzerland: Trans Tech Publications Ltd, 2024. http://dx.doi.org/10.4028/p-8rv6cm.
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The utilization of waste materials in concrete production can provide potential technical and environmental benefits. In this study, the incorporation of recycled waste glass and olive stone aggregates as partial replacements for fine and coarse aggregates in concrete mixtures was evaluated. Coarse aggregate was replaced with crushed bottle glass, while fine aggregate was replaced with processed olive stones from agricultural waste. Five concrete mixtures were tested, with a control mixture containing 0% waste aggregates and others containing 10%, 20%, 30%, and 40% replacements by weight of aggregates with waste glass and olive stones. The compressive strength, flexural strength, and thermal conductivity of standard concrete and specimens were evaluated. The results indicate that compressive strength was equal to or higher in the waste aggregate concretes compared to the control, with 20-30% of replacements showing the best performance. The olive stones increased flexural strength, while the glass reduced it compared to control samples. Thermal conductivity decreased linearly with increasing waste aggregate content due to the lower density and non-crystalline structures. These findings provide evidence that recycled glass and olive stone aggregates can be successfully used as sustainable substitutes for natural aggregates in concrete mixtures.
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"Durability of Concrete with Recycled Fine Aggregate". In SP-234: Seventh CANMET/ACI International Conference on Durability of Concrete. American Concrete Institute, 2006. http://dx.doi.org/10.14359/15952.
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Boukhelkhal, Aboubakeur. "Hardened Properties of Self-Compacting Concrete Incorporating Recycled Granite Waste as Fine Aggregate". In The 2nd International Conference on Civil Infrastructure and Construction. Qatar University Press, 2023. http://dx.doi.org/10.29117/cic.2023.0107.
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The present paper investigates the hardened properties of self-compacting concrete by reusing granite waste to replace natural fin aggregates. The reuse of solid wastes as powder or aggregates allows us to produce sustainable concretes that have lower environmental impacts and reduced cost. In this work, granite waste was used as a partial replacement to natural river sand in self-compacting concrete (SCC). For this purpose, four mixtures were designed in which three contained a combination of river sand (RS) and recycled granite (RG) and one only included river sand (RS) as reference mix. Compressive strength, flexural strength, ultrasonic pulse velocity and water absorption were investigated for the hardened SCC at 28 days of hydration. The results showed that the introduction of RG has no effect on compressive strength of SCC. Adding 30% of RG increased flexural strength by 12%. According to ultrasonic pulse velocity results, the use of RG resulted in more compactness and homogeneous SCC. In addition, SCC including RG showed less water absorption.
Relatórios de organizações sobre o assunto "Recycled concrete fines"
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Mattapalli, Akhila, e Yang Lu. Thermodynamic Study of Carbon Mineralization with Recycled Concrete Fines for Carbon Capture and Utilization Applications. Peeref, julho de 2022. http://dx.doi.org/10.54985/peeref.2207p6658185.
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