ce/papers最新文献_第10页

Leistungsbezogene Bewertung der Dauerhaftigkeit von Betonbauwerken durch baustellentaugliche Abnahmeprüfungen 评估混凝土结构通过工地进行预检测对其可行性的评估

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2915

David Ov, Juan Mauricio Lozano-Valcarcel, Rolf Breitenbücher, Thomas Kränkel, Christoph Gehlen

{"title":"Leistungsbezogene Bewertung der Dauerhaftigkeit von Betonbauwerken durch baustellentaugliche Abnahmeprüfungen","authors":"David Ov, Juan Mauricio Lozano-Valcarcel, Rolf Breitenbücher, Thomas Kränkel, Christoph Gehlen","doi":"10.1002/cepa.2915","DOIUrl":"https://doi.org/10.1002/cepa.2915","url":null,"abstract":"<div>\u0000 \u0000 <p>Für die Dauerhaftigkeit eines Bauwerks ist die Qualität des eingebauten Betons entscheidend. Allerdings sind bislang für die dauerhaftigkeitsrelevanten Betoneigenschaften noch keine direkten Bewertungskriterien definiert worden. Die Qualität des eingebauten Betons wird in der Regel an separat hergestellten Proben nachgewiesen. Vergangene Forschungsarbeiten haben gezeigt, dass die am Bauwerk erzielten Betoneigenschaften von denen der separat hergestellten Proben erheblich abweichen können. In dem künftigen performance-basierten Dauerhaftigkeitskonzept ist zudem die direkte Prüfung der relevanten Parameter (Karbonatisierungsrate, Chlorideindringung usw.) mit einem vergleichsweise hohen Aufwand verbunden. Es wird in der Praxis ohnehin nicht umsetzbar sein, die dauerhaftigkeitsrelevanten Eigenschaften im hinreichenden Umfang über die direkten Prüfverfahren zu überwachen. Vielmehr ist die Qualität des Betons auf der Baustelle durch indirekte Schnellprüfverfahren (z.B. Wenner-Sonde) zu bewerten, die damit verbunden in engeren Zeitabständen durchführbar und somit auch baustellengerecht sind. Hierzu liegen jedoch noch keine ausreichenden Erfahrungen über die Anwendbarkeit und Reproduzierbarkeit auf den Baustellen vor.</p>\u0000 </div>","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"1493-1504"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cepa.2915","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Eignung des RCM-Versuchs zur Bestimmung des Chloridmigrationskoeffizienten in Mörteln aus alternativen Bindemitteln 我的视力与先前的婴儿不配

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2974

Rebecca Achenbach, Bettina I. E. Kraft, Michael Raupach, Horst-Michael Ludwig

{"title":"Eignung des RCM-Versuchs zur Bestimmung des Chloridmigrationskoeffizienten in Mörteln aus alternativen Bindemitteln","authors":"Rebecca Achenbach, Bettina I. E. Kraft, Michael Raupach, Horst-Michael Ludwig","doi":"10.1002/cepa.2974","DOIUrl":"https://doi.org/10.1002/cepa.2974","url":null,"abstract":"<div>\u0000 \u0000 <p>Die Hauptursache für die Korrosion von Bewehrungsstahl vor allem in Infrastrukturbauwerken ist das Eindringen von Chloriden, die am Stahl zu hohen Korrosionsraten und großen Querschnittsverlusten führen können. Ein häufig verwendetes beschleunigtes Testverfahren ist der Rapid Chloride Migration (RCM)-Test, mit dem der Chlorideindringwiderstand von Betonen und Mörteln anhand eines im elektrischen Feld ermittelten Migrationskoeffizienten bewertet wird. Die neuartigen Bindemittel, die mit geringerem CO<sub>2</sub>-Ausstoß hergestellt werden können als reiner Portlandzement (PZ), unterscheiden sich teilweise in ihren Porenlösungszusammensetzungen von PZ-basierten Systemen. Daher besteht die aktuelle Fragestellung, ob die zur Berechnung des Migrationskoeffizienten notwendige und in den aktuellen Prüfvorschriften angegebene Chloridkonzentration, die den Farbumschlag der Indikatorlösung zur Bestimmung der Chlorideindringtiefe auslöst, für diese Bindemittel gültig ist. Zur Klärung dieser Fragestellung wurden an neun verschiedenen Mörteln aus alternativen Bindemitteln der RCM-Versuch und weitere Untersuchungen zur Bestimmung des Chloridgehaltes in der Tiefe des Farbumschlags durchgeführt und die Auswirkungen auf die ermittelten Migrationskoeffizienten dargestellt.</p>\u0000 </div>","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"1237-1245"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cepa.2974","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Frosteinfluss auf den Chloridtransport in Beton - Kennwerte 奎刚师父师父

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2953

Christoph Langer, Gesa Kapteina

{"title":"Frosteinfluss auf den Chloridtransport in Beton - Kennwerte","authors":"Christoph Langer, Gesa Kapteina","doi":"10.1002/cepa.2953","DOIUrl":"https://doi.org/10.1002/cepa.2953","url":null,"abstract":"<div>\u0000 \u0000 <p>Im Winter wird überwiegend das Salz NaCl zur Aufrechterhaltung der Verkehrssicherheit auf Straßen und andere Infrastrukturbauwerke gestreut. Die in der Eisschmelze vorhandenen Chloridionen dringen in den Stahlbeton überwiegend durch die Transportprozesse Diffusion und Konvektion ein. Durch die Exposition Frost (XF) kann es zur Koppelung der Transportprozesse kommen und den Chlorideintrag in Hinblick auf die eingetragene Menge und Tiefe erhöhen. Betone, die bereits im CDF-Test mit NaCl beaufschlagt wurden, werden zu verschiedenen Zeitpunkten im Migrationstest auf die Widerstandsfähigkeit gegenüber erneutem Ioneneindringen (Bromidionen, RBM-Versuch) getestet. Dadurch kann der Einfluss der Frost-Tausalz-Wechsel (FTSW) des CDF-Versuches auf das Bromideindringen im anschließenden Migrationsversuch (RBM) untersucht werden. Die Quantifizierung der Chlorid- und Bromidgehalte erfolgt mit der Laser-Induzierten Breakdown Spektroskopie (LIBS). Ergänzende Untersuchungen wie die Fluoreszenzmikroskopie liefern weitere Erkenntnisse, die auf das Wirken von Frost in der Konvektionszone zurückzuführen sind. Durch die Kombination der Laborversuche CDF- und Migrationsversuch (RBM) können unter Einbezug der LIBS-Analyse Kennwerte ermittelt werden, die den Frosteinfluss auf den Chloridtransport in Beton quantifizierbar machen.</p>\u0000 </div>","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"1205-1213"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cepa.2953","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Vorwort | Preface

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.3014

引用次数: 0

Challenges for Embedding RFID Sensors in Reinforced Concrete for Low-effort Structural Health Monitoring 在钢筋混凝土中嵌入射频识别传感器进行低强度结构健康监测的挑战

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2893

Christian Walther, Feras Alkam, Long Nguyen-Tuan, Matthias Lieboldt, Tom Lahmer

{"title":"Challenges for Embedding RFID Sensors in Reinforced Concrete for Low-effort Structural Health Monitoring","authors":"Christian Walther, Feras Alkam, Long Nguyen-Tuan, Matthias Lieboldt, Tom Lahmer","doi":"10.1002/cepa.2893","DOIUrl":"https://doi.org/10.1002/cepa.2893","url":null,"abstract":"The structural health of civil infrastructure can be monitored using non‐destructive testing methods and wireless sensor technology. Buildings are often made of reinforced concrete, in which the sensors can be embedded during construction. The implementation of sensor‐based monitoring therefore fundamentally requires robust electronics. The wireless sensors must meet the special requirements of different areas such as communication, durability in the concrete, and compatibility with future readers. Taking into account previous approaches from practice and research, an elicitation of basic requirements for a Radio Frequency Identification (RFID) sensor system that can be embedded in concrete was carried out. Specific problems related to embedding electronic sensors in concrete and their design are investigated. Simple RFID sensor systems have been developed that allow operation without cables or batteries. The main sensor requirements are listed accordingly. Challenges and issues that need to be considered when using RFID sensors in concrete are described. Finally, the “life cycle” of a sensor system embedded in reinforced concrete is briefly discussed.","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"1460-1469"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cepa.2893","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quellverhalten von Portland- und Hochofenzementstein bei unterschiedlichen Temperaturen 同时气温偏高的波特兰和高音部的失常状态

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2918

Falk Wagemann, Frank Schmidt-Döhl, Amir Rahimi

{"title":"Quellverhalten von Portland- und Hochofenzementstein bei unterschiedlichen Temperaturen","authors":"Falk Wagemann, Frank Schmidt-Döhl, Amir Rahimi","doi":"10.1002/cepa.2918","DOIUrl":"https://doi.org/10.1002/cepa.2918","url":null,"abstract":"<div>\u0000 \u0000 <p>Zementgebundene Baustoffe quellen bei permanenter Wasserlagerung, d. h., sie erfahren eine zeitabhängige Volumenzunahme. Wesentlich für das Quellverhalten zementgebundener Baustoffe ist der volumetrische Anteil an Zementstein. Für Bereiche, in denen Betonbauteile permanent einer Wasserumgebung ausgesetzt sind, wie zum Beispiel bei Gründungen im Grundwasser, kann das Quellverhalten ggf. die Tragwirkung verbessern, da sich Bauteile im Boden infolge des Quelldruckes verspannen. Dieser Beitrag untersucht das Quellverhalten von Zementstein aus CEM I und CEM III/B mit w/z-Werten von 0,3 und 0,5 bei 10 °C und 20 °C betrachtet. Zusätzlich wurden im Rahmen der Untersuchungen Zementsuspensionen verpresst, um Filtrationseffekte abzubilden. Neben dem Quellmaß zu verschiedenen Zeitpunkten (1, 3, 5, 7, 14, 28 und 56 Tage) wurde der Hydratationsgrad und Gehalt an Calciumhydroxid mit Hilfe der Thermogravimetrie und die Porosität mittels Quecksilberdruckporosimetrie als Materialkennwerte bestimmt. Die Untersuchungsmethoden erlauben einen Rückschluss von Porosität und Hydratphasenausbildung auf das Quellverhalten der untersuchten Zementsteine zu ziehen. Bei beiden Zementarten führen niedrigere Lagerungstemperaturen zu höheren Quellmaßen.</p>\u0000 </div>","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"1091-1100"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cepa.2918","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Erratum to: Changes to the lambda model for fatigue loads on steel railway bridges in Europe 对欧洲钢铁路桥梁疲劳荷载lambda模型的修改的勘误

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.3013

引用次数: 0

Preventing Alkali-Silica Reaction in Concrete 防止混凝土中的碱-硅反应

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2935

Jason H. Ideker, Thano Drimalas, Kevin J. Folliard, Ardalan Ghanizadeh, Anuj Parashar, Krishna Siva Teja Chopperla, April Snyder, Michael D.A. Thomas

{"title":"Preventing Alkali-Silica Reaction in Concrete","authors":"Jason H. Ideker, Thano Drimalas, Kevin J. Folliard, Ardalan Ghanizadeh, Anuj Parashar, Krishna Siva Teja Chopperla, April Snyder, Michael D.A. Thomas","doi":"10.1002/cepa.2935","DOIUrl":"https://doi.org/10.1002/cepa.2935","url":null,"abstract":"<div>\u0000 \u0000 <p>Alkali-silica reaction continues to be a challenging durability issue for portland cement-based concrete. While myriad of preventive options is known to reduce the risk of ASR, changes in availability and consistency of materials make either prescriptive or performance-based approaches difficult to develop and then quickly adapt. In general, the research community has supported industry with practical solutions based on empirically derived relationships, mostly from accelerated test methods and to a lesser extent realistic exposure/field structures. It is time to increase the level of science behind our approach. The research team represented in this talk is investigating a new methodology that combines the alkali availability needed to initiate ASR (aggregate specific) with the available alkali from the total cementitious blend. The relationship between reactivity of a supplementary cementitious material and the ASR expansion is also explored. This keynote lecture will: 1) Explore performance-based testing versus prescriptive approaches and why a hybrid approach should be considered ASR prevention; 2) Evaluate the relationship between accelerated laboratory tests, outdoor exposure blocks and field structures; 3) Examine the use of “non-traditional” supplementary cementitious materials and/or chemical admixtures to prevent alkali-silica reaction; 4) Propose future research needs and; 5) Make recommendations for how best to prevent alkali-silica reactivity following the proposed approach.</p>\u0000 </div>","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"1101-1109"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cepa.2935","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Increase in physical and mechanical properties of decorative concretes for the post-war restoration of residential and public buildings in the Kharkiv region with the addition of highly dispersed calcite (chalk) 增加装饰混凝土的物理和机械性能，用于哈尔科夫地区住宅和公共建筑的战后修复，添加高度分散的方解石(白垩)

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2793

Svitlana Chepurna, Olena Dudka, Yevhenii Chepurnyi

{"title":"Increase in physical and mechanical properties of decorative concretes for the post-war restoration of residential and public buildings in the Kharkiv region with the addition of highly dispersed calcite (chalk)","authors":"Svitlana Chepurna, Olena Dudka, Yevhenii Chepurnyi","doi":"10.1002/cepa.2793","DOIUrl":"https://doi.org/10.1002/cepa.2793","url":null,"abstract":"<p>During the war active, a huge number of residential and public buildings were destroyed not only in Kharkiv and the region, but throughout Ukraine. For the restoration of destroyed buildings, new types of cement will be needed to look for and will be created decorated concretes based on them that would provide high operational and technological properties of constrictions and will be focused on local materials. Carbonate additive such as highly dispersed calcite (chalk) can be used for as local additive for concrete due to significant reserves are located in Kharkiv region. In the article research on the impact of joint action additive of highly dispersed calcite (chalk) and natural pigment (ocher) is presented by physical and mechanical properties such as density, strength, water resistance, and frost resistance. It has been established that, depending on the percentage of highly dispersed calcite (chalk), the physical and mechanical properties are changed irregularly. On the basis of the conducted researches it was established that the optimal amount of the addition of high-fossil chalk, which provides increased frost resistance and corrosion resistance of concrete in an aggressive environment, containing chlorides, sulfates and magnesium ions, is from 10 % to 30 %. In addition, it increases density, compressive strength, stretching strength at bending. At the same time, it should be noted at an increased amount of fine chalk to 40% leads to a decrease in physical and mechanical characteristics. But the introduction of plasticizer in the amount of 0.5% leads to increased compressive strength and, accordingly, increases the positive qualities of chalk. The concrete compositions that getting with high decorative and operational properties are allowed to use them for the restoration of the city and increase in urban space.</p>","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"1429-1433"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Shotcrete 3D Printing - Interaction of nozzle geometry, homogeneity and hardened concrete properties 喷射混凝土3D打印-喷嘴几何形状、均匀性和硬化混凝土特性的相互作用

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2818

Niklas Freund, Martin David, David Böhler, Inka Mai, Stefan Ullmann, Klaus Dröder, Dirk Lowke

{"title":"Shotcrete 3D Printing - Interaction of nozzle geometry, homogeneity and hardened concrete properties","authors":"Niklas Freund, Martin David, David Böhler, Inka Mai, Stefan Ullmann, Klaus Dröder, Dirk Lowke","doi":"10.1002/cepa.2818","DOIUrl":"https://doi.org/10.1002/cepa.2818","url":null,"abstract":"<div>\u0000 \u0000 <p>Shotcrete 3D Printing (SC3DP) applies concrete layer by layer using a wet-spray process. The resulting hardened concrete properties of the applied SC3DP layers (e.g. height, width or mechanical strength) are largely dependent on the selected material and process parameters. In this context, the nozzle geometry is an important influencing parameter. During printing, the velocity of the shotcrete jet is significantly influenced by the nozzle outlet diameter. Therefore, in the present study, the effect of the nozzle outlet diameter (15 - 30 mm) is investigated with regard to the resulting layer homogeneity, i.e. local density and aggregate distribution in the cross-section, and hardened concrete properties, i.e. flexural strength. By analysing the manufactured specimens, an uneven distribution of the aggregate is observed horizontally across the cross-section of the layers. An accumulation of aggregate is present in the core of the layer resulting in a cement paste-rich region in the edge areas. This leads to increased local densities in the core of the specimen. The application of the concrete with small nozzle outlet diameters results in the highest local densities and the highest flexural strength.</p>\u0000 </div>","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"746-754"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cepa.2818","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0