Pub Date : 2024-04-09DOI: 10.21809/rilemtechlett.2023.190
Emanuele Rossi, Susanna Governo, Mahdieh Shakoorioskooie, Qianru Zhan, Shishir Mundra, David Mannes, Anders Kaestner, U. Angst
Corrosion of steel reinforcement in concrete is a common degradation mechanism occurring in infrastructures worldwide. Even though extensive research has been conducted over the last decades to accurately predict the influence of steel corrosion on concrete durability, a comprehensive understanding of several micro-scale processes simultaneously involved in the corrosion mechanism is still lacking. The application of X-ray Computed Tomography (X-ray CT) can contribute to elucidate these processes, since this technique allows observing the internal status of specimens non-destructively, over time, and with a spatial resolution in the range of µm. Nevertheless, the relatively low sensitivity of light elements (e.g., hydrogen and oxygen) to X-ray CT may hinder the observation of solution within the cementitious matrix. This consideration is discussed in this letter. The results of this study show that the detection of solution in macropores (e.g., air voids) through X-ray CT is not limited by the relatively low attenuation coefficient of the fluid per se, but more by the spatial resolution at which acquisitions are performed and by the dimensions of the porous volume where solution penetrates. The observations reported in this letter may open several opportunities to further study the influence of the moisture conditions of air voids on several degradation mechanisms of reinforced cementitious materials (e.g., steel corrosion, freeze-thaw damage), which have been rarely investigated with X-ray CT according to the literature. The application of these findings could significantly deepen the understanding of several micro- scale processes that affect the durability of reinforced cementitious materials which still need to be elucidated, as further discussed in the present letter.
混凝土中的钢筋锈蚀是全球基础设施中常见的退化机制。尽管在过去的几十年中已经开展了大量研究，以准确预测钢筋锈蚀对混凝土耐久性的影响，但仍缺乏对锈蚀机理中同时涉及的几个微观过程的全面了解。X 射线计算机断层扫描（X 射线 CT）的应用有助于阐明这些过程，因为这种技术可以非破坏性地观察试样的内部状态、时间变化和微米范围内的空间分辨率。不过，轻元素（如氢和氧）对 X 射线 CT 的灵敏度相对较低，可能会妨碍对水泥基质内溶液的观察。本信将讨论这一问题。本研究的结果表明，通过 X 射线 CT 检测宏观孔隙（如空隙）中的溶液并不受限于流体本身相对较低的衰减系数，而更多地受限于进行采集时的空间分辨率以及溶液穿透的多孔体积的尺寸。根据文献记载，X 射线 CT 很少对钢筋水泥材料的降解机制（如钢筋腐蚀、冻融破坏）进行研究。这些发现的应用可大大加深对影响钢筋水泥基材料耐久性的若干微尺度过程的理解，而这些过程仍有待阐明，这一点将在本信中进一步讨论。
{"title":"X-ray computed tomography to observe the presence of water in macropores of cementitious materials","authors":"Emanuele Rossi, Susanna Governo, Mahdieh Shakoorioskooie, Qianru Zhan, Shishir Mundra, David Mannes, Anders Kaestner, U. Angst","doi":"10.21809/rilemtechlett.2023.190","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.190","url":null,"abstract":"Corrosion of steel reinforcement in concrete is a common degradation mechanism occurring in infrastructures worldwide. Even though extensive research has been conducted over the last decades to accurately predict the influence of steel corrosion on concrete durability, a comprehensive understanding of several micro-scale processes simultaneously involved in the corrosion mechanism is still lacking. The application of X-ray Computed Tomography (X-ray CT) can contribute to elucidate these processes, since this technique allows observing the internal status of specimens non-destructively, over time, and with a spatial resolution in the range of µm. Nevertheless, the relatively low sensitivity of light elements (e.g., hydrogen and oxygen) to X-ray CT may hinder the observation of solution within the cementitious matrix. This consideration is discussed in this letter. The results of this study show that the detection of solution in macropores (e.g., air voids) through X-ray CT is not limited by the relatively low attenuation coefficient of the fluid per se, but more by the spatial resolution at which acquisitions are performed and by the dimensions of the porous volume where solution penetrates. The observations reported in this letter may open several opportunities to further study the influence of the moisture conditions of air voids on several degradation mechanisms of reinforced cementitious materials (e.g., steel corrosion, freeze-thaw damage), which have been rarely investigated with X-ray CT according to the literature. The application of these findings could significantly deepen the understanding of several micro- scale processes that affect the durability of reinforced cementitious materials which still need to be elucidated, as further discussed in the present letter.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":"113 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140724358","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}
Pub Date : 2024-03-01DOI: 10.21809/rilemtechlett.2023.184
H. Cheikh Sleiman, Murilo Henrique Moreira, Alessandro Tengattini, S. Dal Pont
Full-field techniques such as tomography are becoming progressively more central in the study of complex phenomena, in particular where spatiotemporal evolution is crucial, as in moisture transport or crack initiation in porous media. These techniques provide a unique insight in the local process whose quantification allows the improvement of our understanding and of the models describing them. Nevertheless, the model validation can be pushed further by attempting to explicitly represent the heterogeneities and simulate their role in the processes. Once validated, these models can be used to perform “virtual experiments”, and overcome the limitations of the experiments (e.g., sample size and number, fine control of the boundary and initial conditions). This study proposes a connection between tomography images and mesoscale models through a workflow that mainly employs open-source tools. This workflow is illustrated through the digitization of a Portland cement concrete sample, stemming from neutron tomographies and resulting in a numerical finite element mesh. The proposed workflow is flexible, allowing for the conversion of images from various sources, such as x-ray or neutron tomographies, to different numerical representations of the domain, such as finite element meshes or even a discrete domain required by discrete element methods, while preserving real morphologies with an accuracy proportionate to the specific need of the problem. Beside its generalizability, our method also offers automated labelling of the different domains and boundaries in both the volumetric and surface meshes, which is often necessary for assigning material properties and boundary conditions. Finally, the series of image, geometry and mesh processing steps described in this work are made available on a GitHub repository.
层析成像等全场技术在复杂现象的研究中正变得越来越重要，尤其是在时空演变至关重要的情况下，如多孔介质中的水分传输或裂缝萌发。这些技术提供了对局部过程的独特见解，对这些过程的量化有助于提高我们的认识和改进描述这些过程的模型。然而，通过尝试明确表示异质性并模拟其在过程中的作用，可以进一步推动模型验证。这些模型一旦通过验证，就可以用来进行 "虚拟实验"，克服实验的局限性（如样本大小和数量、边界和初始条件的精细控制）。本研究建议通过主要采用开源工具的工作流程，将断层扫描图像与中尺度模型连接起来。该工作流程以波特兰水泥混凝土样本的数字化为例来说明，其源于中子断层扫描，并产生了数值有限元网格。建议的工作流程非常灵活，可将不同来源的图像（如 X 射线或中子断层扫描）转换为不同的域数值表示，如有限元网格，甚至是离散元方法所需的离散域，同时保留真实形态，其精度与问题的特定需求成正比。除通用性外，我们的方法还能自动标注体积网格和曲面网格中的不同域和边界，这对于分配材料属性和边界条件来说通常是必要的。最后，这项工作中描述的一系列图像、几何和网格处理步骤可在 GitHub 存储库中获取。
{"title":"From tomographic imaging to numerical simulations: an open-source workflow for true morphology mesoscale FE meshes","authors":"H. Cheikh Sleiman, Murilo Henrique Moreira, Alessandro Tengattini, S. Dal Pont","doi":"10.21809/rilemtechlett.2023.184","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.184","url":null,"abstract":"Full-field techniques such as tomography are becoming progressively more central in the study of complex phenomena, in particular where spatiotemporal evolution is crucial, as in moisture transport or crack initiation in porous media. These techniques provide a unique insight in the local process whose quantification allows the improvement of our understanding and of the models describing them. Nevertheless, the model validation can be pushed further by attempting to explicitly represent the heterogeneities and simulate their role in the processes. Once validated, these models can be used to perform “virtual experiments”, and overcome the limitations of the experiments (e.g., sample size and number, fine control of the boundary and initial conditions). This study proposes a connection between tomography images and mesoscale models through a workflow that mainly employs open-source tools. This workflow is illustrated through the digitization of a Portland cement concrete sample, stemming from neutron tomographies and resulting in a numerical finite element mesh. The proposed workflow is flexible, allowing for the conversion of images from various sources, such as x-ray or neutron tomographies, to different numerical representations of the domain, such as finite element meshes or even a discrete domain required by discrete element methods, while preserving real morphologies with an accuracy proportionate to the specific need of the problem. Beside its generalizability, our method also offers automated labelling of the different domains and boundaries in both the volumetric and surface meshes, which is often necessary for assigning material properties and boundary conditions. Finally, the series of image, geometry and mesh processing steps described in this work are made available on a GitHub repository.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":" 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140091204","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}
Pub Date : 2024-02-23DOI: 10.21809/rilemtechlett.2023.188
Kent Harries, Luisa Molari
Methods for material characterisation of bamboo necessary for the structural design of bamboo and its expanded use in the construction sector are described. Directions for revising the nascent existing ISO 22157:2019 standard and future directions for this standard are discussed. Critical needs identified include i) improved performance of standard shear and flexural tests; ii) the need to establish protocols and methods for quantifying the long-term behaviour of bamboo and its degradation under environmental exposure; and, iii) establishing the efficacy of emerging methods of bamboo treatment. Requirements are placed in the test standards – grading – structural design ecosystem and are intended to guide future revisions of test and design standards.
介绍了竹材结构设计所需的竹材材料特性分析方法，以及竹材在建筑领域的广泛应用。讨论了修订现行 ISO 22157:2019 标准的方向以及该标准的未来发展方向。确定的关键需求包括：i) 提高标准剪切和弯曲试验的性能；ii) 需要建立协议和方法，量化竹材的长期行为及其在环境暴露下的降解；iii) 确定新出现的竹材处理方法的功效。测试标准--分级--结构设计生态系统中的要求旨在指导未来测试和设计标准的修订。
{"title":"Mechanical characterisation of bamboo for construction: the state-of-practice and future prospects","authors":"Kent Harries, Luisa Molari","doi":"10.21809/rilemtechlett.2023.188","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.188","url":null,"abstract":"Methods for material characterisation of bamboo necessary for the structural design of bamboo and its expanded use in the construction sector are described. Directions for revising the nascent existing ISO 22157:2019 standard and future directions for this standard are discussed. Critical needs identified include i) improved performance of standard shear and flexural tests; ii) the need to establish protocols and methods for quantifying the long-term behaviour of bamboo and its degradation under environmental exposure; and, iii) establishing the efficacy of emerging methods of bamboo treatment. Requirements are placed in the test standards – grading – structural design ecosystem and are intended to guide future revisions of test and design standards.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":"6 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140436352","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}
Pub Date : 2024-02-01DOI: 10.21809/rilemtechlett.2023.186
Emmanuel Keita, Arnaud Perrot
With the overall aim of supporting the development of new construction techniques and materials that are more economical and less carbon intensive, RILEM has decided to launch three new technical committees on earth construction in 2022. One of these committees will focus on the manufacturing processes used in earth construction (TC PEM). The aim of this committee is to bring together experts from several disciplines (materials science, earth construction, rheology, geotechnics, cement chemistry, etc.) to advance earth construction techniques by sharing and promoting good practice. The processing of earth is today based on solid empirical knowledge which fails to convince structural design engineers. As a result, earth construction is still limited to small buildings. To upscale the use of earthen material in construction, it is required to provide a solid scientific background that can be used for the writing of standards and recommendations to guarantee minimal performances in service. Areas of work include improving understanding of the mechanical behaviour of the material in the fresh state, developing characterization methods, monitoring the material during curing, and studying new construction techniques, particularly digital ones. The work of the technical committee PEM “Processing of earth-based materials” is expected to gather the scientific knowledge that can be further used for the writing of construction and design codes for earthen materials.
{"title":"Processing of earth-based materials: current situation and challenges ahead","authors":"Emmanuel Keita, Arnaud Perrot","doi":"10.21809/rilemtechlett.2023.186","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.186","url":null,"abstract":"With the overall aim of supporting the development of new construction techniques and materials that are more economical and less carbon intensive, RILEM has decided to launch three new technical committees on earth construction in 2022. One of these committees will focus on the manufacturing processes used in earth construction (TC PEM). The aim of this committee is to bring together experts from several disciplines (materials science, earth construction, rheology, geotechnics, cement chemistry, etc.) to advance earth construction techniques by sharing and promoting good practice. The processing of earth is today based on solid empirical knowledge which fails to convince structural design engineers. As a result, earth construction is still limited to small buildings. To upscale the use of earthen material in construction, it is required to provide a solid scientific background that can be used for the writing of standards and recommendations to guarantee minimal performances in service. Areas of work include improving understanding of the mechanical behaviour of the material in the fresh state, developing characterization methods, monitoring the material during curing, and studying new construction techniques, particularly digital ones. The work of the technical committee PEM “Processing of earth-based materials” is expected to gather the scientific knowledge that can be further used for the writing of construction and design codes for earthen materials.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":"24 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139883601","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}
Pub Date : 2024-02-01DOI: 10.21809/rilemtechlett.2023.186
Emmanuel Keita, Arnaud Perrot
With the overall aim of supporting the development of new construction techniques and materials that are more economical and less carbon intensive, RILEM has decided to launch three new technical committees on earth construction in 2022. One of these committees will focus on the manufacturing processes used in earth construction (TC PEM). The aim of this committee is to bring together experts from several disciplines (materials science, earth construction, rheology, geotechnics, cement chemistry, etc.) to advance earth construction techniques by sharing and promoting good practice. The processing of earth is today based on solid empirical knowledge which fails to convince structural design engineers. As a result, earth construction is still limited to small buildings. To upscale the use of earthen material in construction, it is required to provide a solid scientific background that can be used for the writing of standards and recommendations to guarantee minimal performances in service. Areas of work include improving understanding of the mechanical behaviour of the material in the fresh state, developing characterization methods, monitoring the material during curing, and studying new construction techniques, particularly digital ones. The work of the technical committee PEM “Processing of earth-based materials” is expected to gather the scientific knowledge that can be further used for the writing of construction and design codes for earthen materials.
{"title":"Processing of earth-based materials: current situation and challenges ahead","authors":"Emmanuel Keita, Arnaud Perrot","doi":"10.21809/rilemtechlett.2023.186","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.186","url":null,"abstract":"With the overall aim of supporting the development of new construction techniques and materials that are more economical and less carbon intensive, RILEM has decided to launch three new technical committees on earth construction in 2022. One of these committees will focus on the manufacturing processes used in earth construction (TC PEM). The aim of this committee is to bring together experts from several disciplines (materials science, earth construction, rheology, geotechnics, cement chemistry, etc.) to advance earth construction techniques by sharing and promoting good practice. The processing of earth is today based on solid empirical knowledge which fails to convince structural design engineers. As a result, earth construction is still limited to small buildings. To upscale the use of earthen material in construction, it is required to provide a solid scientific background that can be used for the writing of standards and recommendations to guarantee minimal performances in service. Areas of work include improving understanding of the mechanical behaviour of the material in the fresh state, developing characterization methods, monitoring the material during curing, and studying new construction techniques, particularly digital ones. The work of the technical committee PEM “Processing of earth-based materials” is expected to gather the scientific knowledge that can be further used for the writing of construction and design codes for earthen materials.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":"158 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139823657","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}
Pub Date : 2024-01-19DOI: 10.21809/rilemtechlett.2023.183
Reza Moini
This paper presents perspectives and progress in the emerging field of architected infrastructure materials. Recent developments in advanced and additive manufacturing with construction materials have led to new capabilities to define, design, and shape the internal arrangement and overall morphology of materials. In contrast to conventional casting techniques used in the construction of civil engineering materials, such advancements have allowed for purposeful designs of materials into specific morphologies across scales, referred to as architected infrastructure materials. Contrary to monolithic construction materials, architected materials present new opportunities to engineer enhanced mechanical properties and unique performance characteristics in civil infrastructure components through design. Here, we present an overview of the field and the research gaps in design, manufacturing, and materials mechanics. An overview of a few design opportunities, including bio-inspired strategies is discussed. Current advancements in the field are presented focusing on cement-based, non-hydraulic, and cementitious composite architected materials. The existing studies on bouligand, cellular, lattice, auxetic, tabulated, and gradient architected construction materials and their mechanically advantageous characteristics are reviewed. The future directions and perspectives for the field are outlined with respect to the current research gaps and upcoming opportunities.
{"title":"Perspectives in architected infrastructure materials","authors":"Reza Moini","doi":"10.21809/rilemtechlett.2023.183","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.183","url":null,"abstract":"This paper presents perspectives and progress in the emerging field of architected infrastructure materials. Recent developments in advanced and additive manufacturing with construction materials have led to new capabilities to define, design, and shape the internal arrangement and overall morphology of materials. In contrast to conventional casting techniques used in the construction of civil engineering materials, such advancements have allowed for purposeful designs of materials into specific morphologies across scales, referred to as architected infrastructure materials. Contrary to monolithic construction materials, architected materials present new opportunities to engineer enhanced mechanical properties and unique performance characteristics in civil infrastructure components through design. Here, we present an overview of the field and the research gaps in design, manufacturing, and materials mechanics. An overview of a few design opportunities, including bio-inspired strategies is discussed. Current advancements in the field are presented focusing on cement-based, non-hydraulic, and cementitious composite architected materials. The existing studies on bouligand, cellular, lattice, auxetic, tabulated, and gradient architected construction materials and their mechanically advantageous characteristics are reviewed. The future directions and perspectives for the field are outlined with respect to the current research gaps and upcoming opportunities.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":"14 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139525059","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}
Pub Date : 2024-01-09DOI: 10.21809/rilemtechlett.2023.187
Nicolas Dowdy, W. Srubar
Biomineralization refers to the biological processes through which living organisms produce minerals. In recent years, biomineralizing microorganisms have been used to stabilize soil or to impart a self-healing or self-sealing mechanism to damaged cement and concrete materials. However, applications of biominerals in cement and concrete research can extend far beyond these applications. This article focuses on the biomineralization of calcium carbonate (CaCO3) and silicon dioxide (SiO2) and their past, present, and future potential applications in cement and concrete research. First, we review the mechanisms of CaCO3 and SiO2 biomineralization and the micro- and macroorganisms involved in their production. Second, we showcase the wide array of biomineral architectures, with an explicit focus on CaCO3 polymorphs and SiO2 morphologies found in nature. Third, we briefly summarize previous applications of CaCO3 and SiO2 biomineralization in cement and concrete research. Finally, we discuss emerging applications of biominerals in cement and concrete research, including mineral admixtures or raw meal for portland cement production, as well as other applications that extend beyond self-healing.
{"title":"Biomineralization in cement and concrete research","authors":"Nicolas Dowdy, W. Srubar","doi":"10.21809/rilemtechlett.2023.187","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.187","url":null,"abstract":"Biomineralization refers to the biological processes through which living organisms produce minerals. In recent years, biomineralizing microorganisms have been used to stabilize soil or to impart a self-healing or self-sealing mechanism to damaged cement and concrete materials. However, applications of biominerals in cement and concrete research can extend far beyond these applications. This article focuses on the biomineralization of calcium carbonate (CaCO3) and silicon dioxide (SiO2) and their past, present, and future potential applications in cement and concrete research. First, we review the mechanisms of CaCO3 and SiO2 biomineralization and the micro- and macroorganisms involved in their production. Second, we showcase the wide array of biomineral architectures, with an explicit focus on CaCO3 polymorphs and SiO2 morphologies found in nature. Third, we briefly summarize previous applications of CaCO3 and SiO2 biomineralization in cement and concrete research. Finally, we discuss emerging applications of biominerals in cement and concrete research, including mineral admixtures or raw meal for portland cement production, as well as other applications that extend beyond self-healing.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":"43 27","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139442600","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}
Pub Date : 2023-12-05DOI: 10.21809/rilemtechlett.2023.181
Derk Bos, Rob Wolfs
The quality control of digital fabrication with concrete has more stringent requirements than traditional casting. Firstly, since formwork is typically absent, or removed at an early stage in production, the material is exposed to external influences that can result in deformations, collapse, or deterioration. Therefore, the evolution of properties during the process has to be controlled. Secondly, the fabrication systems are typically more sensitive to dosing fluctuations, and the produced, optimized objects are more sensitive to defects, which requires the process variations to be controlled at a higher resolution. A framework is presented that categorizes quality control experiments into destructive and non-destructive, according to their systematic error, and according to the location of testing with respect to the process. This framework is applied to the fresh state mechanical performance of concrete and quality control strategies are derived from it. Lastly, research gaps are identified that are critical for the further development and adoption of these quality control strategies in digitally fabricated concrete.
{"title":"A quality control framework for digital fabrication with concrete","authors":"Derk Bos, Rob Wolfs","doi":"10.21809/rilemtechlett.2023.181","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.181","url":null,"abstract":"The quality control of digital fabrication with concrete has more stringent requirements than traditional casting. Firstly, since formwork is typically absent, or removed at an early stage in production, the material is exposed to external influences that can result in deformations, collapse, or deterioration. Therefore, the evolution of properties during the process has to be controlled. Secondly, the fabrication systems are typically more sensitive to dosing fluctuations, and the produced, optimized objects are more sensitive to defects, which requires the process variations to be controlled at a higher resolution. A framework is presented that categorizes quality control experiments into destructive and non-destructive, according to their systematic error, and according to the location of testing with respect to the process. This framework is applied to the fresh state mechanical performance of concrete and quality control strategies are derived from it. Lastly, research gaps are identified that are critical for the further development and adoption of these quality control strategies in digitally fabricated concrete.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":"131 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138599151","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}
Pub Date : 2023-11-24DOI: 10.21809/rilemtechlett.2023.163
Alastair Marsh, Thomas Dillon, Susan A. Bernal
Decarbonisation is the most urgent issue facing the cement and concrete industries, with an aim to reach net-zero carbon dioxide emissions by 2050. In response to this, several decarbonisation roadmaps have been published in recent years, to explore routes for how different decarbonisation strategies can be used to achieve this aim. However, there is a lack of understanding around the similarities and differences between these roadmaps. In this study a meta-analysis of nine cement and concrete sector roadmaps was conducted, with a detailed focus on five roadmaps covering Europe emphasising their applicability within the context of the United Kingdom. Whilst there are some similarities amongst roadmaps in terms of the decarbonisation strategies which are consistently recommended, there are also key differences. Industry roadmaps oriented towards cement-based strategies, whilst non-industry roadmaps were more inclusive of concrete-based strategies. The significance of this study is to highlight the difficulties faced by policymakers and investors in choosing which strategies to prioritise, when there is still considerable uncertainty in the roadmap literature. Recommendations are made for a greater focus on consideration of the construction sector practices which provide more autonomy to practitioners to adopt and implement concrete-based strategies and dematerialisation in future iterations of industry roadmaps, and more research into the capital and operating costs of technological innovations
{"title":"Cement and concrete decarbonisation roadmaps – a meta-analysis within the context of the United Kingdom","authors":"Alastair Marsh, Thomas Dillon, Susan A. Bernal","doi":"10.21809/rilemtechlett.2023.163","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.163","url":null,"abstract":"Decarbonisation is the most urgent issue facing the cement and concrete industries, with an aim to reach net-zero carbon dioxide emissions by 2050. In response to this, several decarbonisation roadmaps have been published in recent years, to explore routes for how different decarbonisation strategies can be used to achieve this aim. However, there is a lack of understanding around the similarities and differences between these roadmaps. In this study a meta-analysis of nine cement and concrete sector roadmaps was conducted, with a detailed focus on five roadmaps covering Europe emphasising their applicability within the context of the United Kingdom. Whilst there are some similarities amongst roadmaps in terms of the decarbonisation strategies which are consistently recommended, there are also key differences. Industry roadmaps oriented towards cement-based strategies, whilst non-industry roadmaps were more inclusive of concrete-based strategies. The significance of this study is to highlight the difficulties faced by policymakers and investors in choosing which strategies to prioritise, when there is still considerable uncertainty in the roadmap literature. Recommendations are made for a greater focus on consideration of the construction sector practices which provide more autonomy to practitioners to adopt and implement concrete-based strategies and dematerialisation in future iterations of industry roadmaps, and more research into the capital and operating costs of technological innovations","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":"3 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139240539","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}
Pub Date : 2023-11-23DOI: 10.21809/rilemtechlett.2023.178
Giorgio Pia, M. Cappai
The improvement in the insulation material performance is one of the recent crucial problems. The energy consumption in the construction and buildings field has a significant impact on the society and the environment. For these reasons, researchers have focused on studying their thermal behaviour in order to improve fabrication methods and material design structures. In this sense, a great contribution has been offered by the modeling procedures. A remarkable attention has been dedicated to the application of fractal geometry which seems to be a promising method to replicate the porous structures as well as to predict the effective thermal conductivity. In this paper, a review of different modeling procedures is presented, comparing both traditional and fractal theory-based approaches. Fractal models demonstrate high reliability in reproducing experimental data under various conditions, including dry and moist systems. This is further enhanced by the application of recursive formulas, which streamline calculations even for complex porous microstructures. The choice between one model and another depends on the specific characteristics of the materials under study. In all cases, the versatility of the analytical procedures enables one to achieve a remarkable agreement with experimental data.
{"title":"Thermal conductivity of porous building materials: An exploration of new challenges in fractal modelling solutions","authors":"Giorgio Pia, M. Cappai","doi":"10.21809/rilemtechlett.2023.178","DOIUrl":"https://doi.org/10.21809/rilemtechlett.2023.178","url":null,"abstract":"The improvement in the insulation material performance is one of the recent crucial problems. The energy consumption in the construction and buildings field has a significant impact on the society and the environment. For these reasons, researchers have focused on studying their thermal behaviour in order to improve fabrication methods and material design structures. In this sense, a great contribution has been offered by the modeling procedures. A remarkable attention has been dedicated to the application of fractal geometry which seems to be a promising method to replicate the porous structures as well as to predict the effective thermal conductivity. In this paper, a review of different modeling procedures is presented, comparing both traditional and fractal theory-based approaches. Fractal models demonstrate high reliability in reproducing experimental data under various conditions, including dry and moist systems. This is further enhanced by the application of recursive formulas, which streamline calculations even for complex porous microstructures. The choice between one model and another depends on the specific characteristics of the materials under study. In all cases, the versatility of the analytical procedures enables one to achieve a remarkable agreement with experimental data.","PeriodicalId":36420,"journal":{"name":"RILEM Technical Letters","volume":"55 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139245935","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}
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