ce/papers最新文献_第10页

Leichter Schaumstein aus groben Porenbetongranulaten im zweiten Nutzungszyklus – RC-Schaumstein 简便泡沫石

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2851

Frank Hlawatsch, Maike Peters, Daniel Ufermann-Wallmeier

引用次数: 0

Characterization of recycled sands and aggregates from selective separation 选择性分离再生砂和骨料的表征

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2867

Encarnacion Vargas-Serrano, W. Tian, N. Mikanovic, Jan Skocek

{"title":"Characterization of recycled sands and aggregates from selective separation","authors":"Encarnacion Vargas-Serrano, W. Tian, N. Mikanovic, Jan Skocek","doi":"10.1002/cepa.2867","DOIUrl":"https://doi.org/10.1002/cepa.2867","url":null,"abstract":"The use of recycling materials from demolished concrete as raw material for structural application represents an opportunity for decreasing the consumption of primary raw materials and waste generation, thus increasing global sustainability. However, this potential is nowadays not fully exploited due to standards limitations and concerns from the construction industry about the negative effect of the recycled sand in the fresh and hardened concrete performance. Thus, most of the recycled sand produced is only reused as roadbed or dumped in the landfill, whereas the recycled coarse aggregate is commonly downcycled when used for lower-grade applications.This paper presents an overview of the quality properties of recycled materials obtained through advanced recycling technologies designed to separate high-quality sand and coarse aggregates from hardened cement paste in demolished concrete. The study focuses on evaluating the selective separation technologies implemented in various industrial pilots and examining how the properties of recycled sands and aggregates compare to those of virgin materials of good quality, and their impact on performance.The test results indicate that there is a strong link between recycled sand quality and its effect on workability and strength development of cement-based materials. This study also identifies critical aggregate parameters based on which one can come up with realistic replacement levels of natural with recycled sands and aggregate without compromising performance in fresh and hardened state. Our intention is to provide sufficient evidence to specifiers and designers that good quality recycled sands can be used in larger amounts in structural concrete.","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"977-983"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502658","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

Einfluss von RC-Gesteinskörnung auf das Druckkriechen eines hochfesten Betons rc岩石结构对高固态岩石压力表的影响

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2868

Martin Markert, Harald Garrecht

引用次数: 0

Application of slags for the production of resource-efficient paving stones 矿渣在资源节约型铺路石生产中的应用

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2887

Taban Shams, Sebastian Dittrich

{"title":"Application of slags for the production of resource-efficient paving stones","authors":"Taban Shams, Sebastian Dittrich","doi":"10.1002/cepa.2887","DOIUrl":"https://doi.org/10.1002/cepa.2887","url":null,"abstract":"<div>\u0000 \u0000 In a recent research project under the lead of the Fraunhofer Institute for Building Physics IBP, gravel and sand within a mixture of paving stones were replaced with LD converter slag and blast furnace slag for 50 wt. % and 100 wt. % to produce resource-efficient concrete components. For this purpose, first, the dry processing of the slags including metal separation and crushing was carried out. In the next step, the particle size distributions of slags using sieve analysis were determined. Finally, the mix designs were set based on the optimum combination of different size fractions of slags. This combination was determined in a way to lead to an almost identical grading curve as that of the original formulation. Splitting tensile strengths of the obtained samples were measured after 14 days of curing under a humidity of 95%. Several paving stone specimens containing slags showed higher splitting tensile strengths than that of the reference sample. Similar results were observed for industrially produced paving stones which demonstrates the successful transfer of the laboratory mixes to the industrial plant.\u0000 </div>","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"1015-1017"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cepa.2887","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502664","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

Influence of calcined clay on micromechanical properties and creep of hardened cement paste 煅烧粘土对硬化水泥浆体微力学性能及蠕变的影响

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2785

Macielle Deiters, Corinna Rozanski, Tobias Schack, Michael Haist

{"title":"Influence of calcined clay on micromechanical properties and creep of hardened cement paste","authors":"Macielle Deiters, Corinna Rozanski, Tobias Schack, Michael Haist","doi":"10.1002/cepa.2785","DOIUrl":"https://doi.org/10.1002/cepa.2785","url":null,"abstract":"<div>\u0000 \u0000 A highly interesting approach to lower CO2 emissions in cement and concrete industry is to reduce the cement clinker content while using supplementary cementitious materials (SCMs) such as calcined clays. Whereas for classical Portland cement clinker, comprehensive studies are already available on the microstructural development during hydration as well as on the resulting macromechanical properties such as compressive strength or long-term deformation behavior, such understanding is missing for calcined clays. In this paper, systematic micromechanical investigations using microindentation of hardened cement pastes with various amounts of calcined clay at ages up to 28 days are presented. The micromechanical results indicate a faster strength development as well as a lower overall porosity of the classical clinker system compared to mixtures containing calcined clay. Looking to creep, the indentation creep modulus is higher for pure OPC mixtures compared to calcined clay systems up to seven days, indicating less pronounced creep. Beyond this age, however, the differences in creep behaviour became less pronounced. The outcomes suggest that the reactivity of the calcined clay seems to be decisive when it comes to mechanical properties and creep behaviour rather than the rate of substitution.\u0000 </div>","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"431-440"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cepa.2785","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502667","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

Activation of LC3 binders by C-S-H nucleation seeding with a new tailored admixture for low-carbon cements 低碳水泥专用新型外加剂C-S-H成核播种活化LC3粘结剂

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2786

Ana Cuesta, Alejandro Morales-Cantero, Angeles G. De la Torre, Isabel Santacruz, Oliver Mazanec, Alessandro Dalla-Libera, Sebastien Dhers, Peter Schwesig, Pere Borralleras, Miguel A.G. Aranda

{"title":"Activation of LC3 binders by C-S-H nucleation seeding with a new tailored admixture for low-carbon cements","authors":"Ana Cuesta, Alejandro Morales-Cantero, Angeles G. De la Torre, Isabel Santacruz, Oliver Mazanec, Alessandro Dalla-Libera, Sebastien Dhers, Peter Schwesig, Pere Borralleras, Miguel A.G. Aranda","doi":"10.1002/cepa.2786","DOIUrl":"https://doi.org/10.1002/cepa.2786","url":null,"abstract":"<div>\u0000 \u0000 The use of supplementary cementitious materials is currently the most favorable strategy for reducing CO2 emissions in cements. Limestone Calcined Clay Cements, LC3, are a type of cement that allows the reduction of CO2 emissions up to 40%. The proportions of the mixtures can vary, but the most investigated combination, LC3-50, contains about 50 wt% clinker, 30 wt% calcined kaolinitic clay, 15 wt% limestone and an optimised calcium sulphate content. However, the mechanical strengths of LC3 at early ages are not good enough and they should be improved. One way of doing this is by employing commercial strength-enhancing (accelerator) admixtures based on C-S-H nucleation seeding. For this work, LC3-50 cements were prepared with clays with varying kaolinite contents. Mortars and pastes were fabricated using a new PCE-based superplasticizer developed to avoid the loss of fluidity at early ages typical of LC3 binders. The selected accelerator for this study was Master X-Seed STE53. The results show that the loss of fluidity of LC3 mortars during the first hours could be solved by a recently developed PCE-based superplasticizer. The compressive strengths at 1 day for LC3 mortars strikingly improved by using the C-S-H seeding admixture and this behavior was maintained for up to 28 days.\u0000 </div>","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"446-453"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/cepa.2786","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502674","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

Mechanochemical Activation of the C-S-H binder Celitement C-S-H粘结剂的机械化学活化

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2906

Daniel Hinder, Adrian Zimmermann, Marc Fylak

引用次数: 0

Clinker-efficient cements and their application - today and tomorrow 高效熟料水泥及其应用——今天和明天

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2824

Christoph Müller

{"title":"Clinker-efficient cements and their application - today and tomorrow","authors":"Christoph Müller","doi":"10.1002/cepa.2824","DOIUrl":"https://doi.org/10.1002/cepa.2824","url":null,"abstract":"The concrete standard DIN 1045-2 currently provides fixed limit formulations for the respective exposure class. The tests of cements in concrete with regard to durability (carbonation, chloride penetration, frost and freeze-thaw salt resistance) are now carried out within approvals procedures in a limit composition for the exposure class under consideration. Test results of clinker-efficient cements are shown against the assessment background of the German Institute for Building Technology (DIBt) e. g. for carbonation: This test is currently to be carried out with a water-cement ratio of w/c = 0.50. While, for example, a CEM III/A or a CEM II/C-M (S-LL) fit well into the assessment background in this test with the required limit composition, the depth of carbonation of a cement is 20 percent clinker, 30 percent blast furnace slag and 50 percent unburned limestone clearly outside. If the water-cement ratio is reduced to w/c = 0.40, the result is already in the upper range of the evaluation background. A further reduction to w/c = 0.35 leads to a result in the range of the reference cements. A further significant reduction in the clinker content in cements with a high proportion of unburnt limestone would therefore be possible if the concretes are composed accordingly.","PeriodicalId":100223,"journal":{"name":"ce/papers","volume":"6 6","pages":"114-126"},"PeriodicalIF":0.0,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138502701","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

A Bogue approach applied to BOF slag Bogue方法在转炉炉渣处理中的应用

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2844

Jonathan Zepper, Katrin Schollbach, Sieger van der Laan, H.J.H Brouwers

引用次数: 0

Resource and energy saving technology of specialpurpose cements 特种水泥资源与节能技术

ce/papers Pub Date : 2023-12-06 DOI: 10.1002/cepa.2980

Olena Khrystych, Halyna Shabanova, Alla Korohodska, Olga Gamova

引用次数: 0