RILEM Technical Letters最新文献_第2页

MgO-based cements – Current status and opportunities 氧化镁基水泥 - 现状与机遇

RILEM Technical Letters Pub Date : 2023-11-16 DOI: 10.21809/rilemtechlett.2023.177

E. Bernard, Hoang Nguyen, S. Kawashima, B. Lothenbach, Hegoi Manzano, John Provis, Allan Scott, C. Unluer, F. Winnefeld, P. Kinnunen

{"title":"MgO-based cements – Current status and opportunities","authors":"E. Bernard, Hoang Nguyen, S. Kawashima, B. Lothenbach, Hegoi Manzano, John Provis, Allan Scott, C. Unluer, F. Winnefeld, P. Kinnunen","doi":"10.21809/rilemtechlett.2023.177","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.177","url":null,"abstract":"The cement industry is a major contributor to the anthropogenic CO2 emissions, with about 8% of all emissions coming from this sector. The global cement and concrete association has set a goal to achieve net-zero CO2 concrete by 2050, with 45% of the reduction coming from alternatives to Portland cement, substitution, and carbon capture and utilization/storage (CCU/S) approaches. Magnesia-based cements offer a conceivable solution to this problem due to their potential for low-to-negative CO2 emissions (CCU/S) but also being alternatives to Portland cement. The sources of magnesia can come from magnesium silicates or desalination brines which are carbon free for raw-material-related emissions (cf. carbonated rocks). This opens up possibilities for low or even net-negative carbon emissions. However, research on magnesia-based cements is still in its early stages. In this paper, we summarize the current understanding of different MgO-based cements and their chemistries: magnesia oxysulfate cement, magnesia oxychloride cement, magnesia carbonate cement, and magnesia silicate cement. We also discuss relevant research needed for MgO-based cements and concretes including the issues relating to the low pH of these cements and suitability of steel reinforcement. Alternatives reinforcements, suitable admixtures, and durability studies are the most needed for the further development of MgO-based concretes to achieve a radical CO2 reduction in this industry. Additionally, techno-economic and life cycle assessments are also needed to assess the competition of raw materials and the produced binder or concrete with other solutions. Overall, magnesia-based cements are a promising emerging technology that requires further research and development to realize their potential in reducing CO2 emissions in the construction industry.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139268142","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

Guidelines for using superabsorbent polymers (SAP) in concrete construction 在混凝土建筑中使用超吸水性聚合物（SAP）的指导原则

RILEM Technical Letters Pub Date : 2023-11-14 DOI: 10.21809/rilemtechlett.2023.182

Viktor Mechtcherine

引用次数: 0

A two-fold strategy towards low-carbon concrete 低碳混凝土的双重战略

RILEM Technical Letters Pub Date : 2023-11-08 DOI: 10.21809/rilemtechlett.2023.179

Franco Zunino

引用次数: 0

The missing link in the bottom-up theory of mechanical properties of calcium silicate hydrate 水合硅酸钙力学性能自下而上理论的缺失环节

RILEM Technical Letters Pub Date : 2023-11-08 DOI: 10.21809/rilemtechlett.2023.180

Guoqing Geng, Zhe Zhang

引用次数: 0

Viscoelastic properties of fresh cement paste: measuring procedures and influencing parameters 新鲜水泥浆的粘弹性特性:测量方法和影响参数

RILEM Technical Letters Pub Date : 2023-08-21 DOI: 10.21809/rilemtechlett.2023.176

A. Yahia, A. Perrot, D. Feys, K. Khayat, M. Sonebi, S. Kawashima, Wolfram Schimdt

{"title":"Viscoelastic properties of fresh cement paste: measuring procedures and influencing parameters","authors":"A. Yahia, A. Perrot, D. Feys, K. Khayat, M. Sonebi, S. Kawashima, Wolfram Schimdt","doi":"10.21809/rilemtechlett.2023.176","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.176","url":null,"abstract":"Fresh cement pastes behave as viscoelastic materials below the flow onset. The measurements of viscoelastic properties of fresh cement paste provide valuable insight into the dispersion of solid particles as well as the hydration kinetics at early age and its influence on the structural evolution and solidification behavior at quasi-static conditions. Monitoring the development of viscoelastic properties of fresh cement paste using dynamic oscillatory shear measurements can also elucidate the working mechanisms of chemical admixtures. These properties are efficient indicators to guide mixture proportion design and are necessary to understand the rheology and stability of concrete. In this paper, the most common techniques, including dynamic oscillatory measurements, used to assess the viscoelastic properties of fresh cement paste are presented and discussed. The measurement challenges and their effects on the accuracy of the obtained properties are highlighted. On the other hand, the effects of high-range water-reducer, viscosity-modifying admixture, and supplementary cementitious materials are discussed. Furthermore, the use of viscoelastic measurements to assess yield stress and structural build-up of cement paste is presented.\u0000 ","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68366200","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: 1

Limestone-Calcined Clay (LC2) as a supplementary cementitious material for concrete 石灰石煅烧粘土(LC2)作为混凝土的补充胶凝材料

RILEM Technical Letters Pub Date : 2023-08-18 DOI: 10.21809/rilemtechlett.2023.172

A. S. Basavaraj, Hareesh Muni, Yuvaraj Dhandapani, R. Gettu, M. Santhanam

{"title":"Limestone-Calcined Clay (LC2) as a supplementary cementitious material for concrete","authors":"A. S. Basavaraj, Hareesh Muni, Yuvaraj Dhandapani, R. Gettu, M. Santhanam","doi":"10.21809/rilemtechlett.2023.172","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.172","url":null,"abstract":"In this work, limestone-calcined clay (LC2) is studied as an alternative supplementary cementitious material (SCM), combining two widely available resources – calcinated kaolinitic clay and limestone, to partially substitute portland clinker. The primary goal is to assess the potential of LC2 to produce moderate to high strength concretes with design compressive strengths of 20 to 50 MPa. For this purpose, 27 mixes with LC2 were prepared with a range of binder contents and water-binder ratios, and the performance was benchmarked against those of mixes having fly ash (PFA). In addition to the quantification of strength and concrete resistivity, life cycle assessment was performed for the concretes considering a typical situation in India. The efficiency of concretes made with LC2, PFA and ordinary portland cement (OPC) was analyzed using the energy intensity index (eics) and apathy index (A-index) as sustainability indicators. This framework establishes the sustainability potential of the LC2 with insights on the influence of strength on the indicators. It is concluded that the LC2 concretes with 45% replacement level, w/b≤0.45 and binder content lower than 400 kg/m3 possess the highest sustainability potential, among the concretes studied here.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44964448","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

Five recommendations to accelerate sustainable solutions in cement and concrete through partnership 通过伙伴关系加快水泥和混凝土可持续解决方案的五项建议

RILEM Technical Letters Pub Date : 2023-07-04 DOI: 10.21809/rilemtechlett.2023.173

Joseph Mwiti Marangu, A. Marsh, D. Panesar, N. Radebe, Alicia Regodon Puyalto, W. Schmidt, L. Valentini

{"title":"Five recommendations to accelerate sustainable solutions in cement and concrete through partnership","authors":"Joseph Mwiti Marangu, A. Marsh, D. Panesar, N. Radebe, Alicia Regodon Puyalto, W. Schmidt, L. Valentini","doi":"10.21809/rilemtechlett.2023.173","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.173","url":null,"abstract":"Though the technical knowledge to make cement and concrete more sustainable already exists, implementation of solutions lags behind the rate needed to mitigate climate change and meet the targets set by the Sustainable Development Goals. Whilst most of the focus around the built environment is on embodied carbon, we stress an important but neglected dimension: partnership (SDG17). Effective partnerships can be powerful enablers to accelerate sustainable solutions in cement and concrete, and let such solutions transfer from academia to the market. This can be achieved through knowledge generation, solution implementation, and policy development, among other routes. In this article, we share five recommendations for how partnerships can address neglected research questions and practical needs: 1) reform Science, Technology, Engineering and Mathematics (STEM) education to train “circular citizens”; 2) map out routes by which cementitious materials can contribute to a “localization” agenda; 3) generate open-access maps for the geographical distribution of primary and secondary raw materials; 4) predict the long-term environmental performance of different solutions for low-CO2 cements in different geographical areas; 5) overhaul standards to be technically and regionally fit for purpose. These approaches have the potential to make a unique and substantial contribution towards achieving collective sustainability goals.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47018078","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

Research needs for cementitious building materials with focus on Europe 水泥建筑材料的研究需求，重点在欧洲

RILEM Technical Letters Pub Date : 2023-04-26 DOI: 10.21809/rilemtechlett.2022.165

K. Scrivener, Mohsen Ben Haha, P. Juilland, Christophe Levy

引用次数: 3

Molecular modelling of cementitious materials: current progress and benefits 胶凝材料的分子建模:目前的进展和好处

RILEM Technical Letters Pub Date : 2023-03-23 DOI: 10.21809/rilemtechlett.2022.175

A. Kunhi Mohamed, A. Bouibes, M. Bauchy, Ziga Casar

引用次数: 3

In-Crease: Less Concrete More Paper 增加:减少混凝土，增加纸张

RILEM Technical Letters Pub Date : 2023-02-20 DOI: 10.21809/rilemtechlett.2022.168

E. Lloret-Fritschi, Joseph Choma, F. Scotto, A. Szabo, F. Gramazio, M. Kohler, R. Flatt

{"title":"In-Crease: Less Concrete More Paper","authors":"E. Lloret-Fritschi, Joseph Choma, F. Scotto, A. Szabo, F. Gramazio, M. Kohler, R. Flatt","doi":"10.21809/rilemtechlett.2022.168","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2022.168","url":null,"abstract":"Concrete is one of the most used materials after water. Largely owing to this, its environmental impact is substantial, although its embodied carbon per unit volume or mass is low when compared to most alternatives. This, along with the broad availability, good strength, durability and versatility of concrete means that it will remain a material of choice, although more efficient ways of using it must be found.\u0000Structurally optimized building components are a means to do this as they can save about 50% material. Unfortunately, however, such elements are presently too expensive to produce owing to them requiring non-standard formwork. It is an objective of digital fabrication to propose solutions to this issue. In this con-text, Digital Casting Systems (DCS) have advanced material control strategies for setting-on-demand in digital concrete processing. Thereby, the formwork pressure is reduced to a minimum, which opens possibilities of rethinking formworks as systems that are dynamically shaping, millimetre thin or weakly supporting the material cast inside.\u0000In this paper we present a brief overview of millimetre thin formworks and summarize the first realization of concrete elements that utilizes the mechanics of paper folding to make millimetre thin formworks up to 2.5 meters high. Such formworks could initially be flat packed, erected into shape, and eventually peeled-off and recycled in established material streams. This would reduce waste and transport cost, while offering a surface finish that meets the expectations for exposed concrete surfaces.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41632742","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