RILEM Technical Letters最新文献

X-ray computed tomography to observe the presence of water in macropores of cementitious materials 通过 X 射线计算机断层扫描观察水泥基材料宏观孔隙中是否存在水分

RILEM Technical Letters Pub Date : 2024-04-09 DOI: 10.21809/rilemtechlett.2023.190

Emanuele Rossi, Susanna Governo, Mahdieh Shakoorioskooie, Qianru Zhan, Shishir Mundra, David Mannes, Anders Kaestner, U. Angst

{"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":null,"pages":null},"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}

引用次数: 0

From tomographic imaging to numerical simulations: an open-source workflow for true morphology mesoscale FE meshes 从断层成像到数值模拟：真实形态中尺度 FE 网格的开源工作流程

RILEM Technical Letters Pub Date : 2024-03-01 DOI: 10.21809/rilemtechlett.2023.184

H. Cheikh Sleiman, Murilo Henrique Moreira, Alessandro Tengattini, S. Dal Pont

{"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":null,"pages":null},"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}

引用次数: 0

Mechanical characterisation of bamboo for construction: the state-of-practice and future prospects 建筑用竹材的力学特征：实践现状与未来展望

RILEM Technical Letters Pub Date : 2024-02-23 DOI: 10.21809/rilemtechlett.2023.188

Kent Harries, Luisa Molari

引用次数: 0

Processing of earth-based materials: current situation and challenges ahead 土基材料加工：当前形势与未来挑战

RILEM Technical Letters Pub Date : 2024-02-01 DOI: 10.21809/rilemtechlett.2023.186

Emmanuel Keita, Arnaud Perrot

{"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":null,"pages":null},"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}

引用次数: 0

Processing of earth-based materials: current situation and challenges ahead 土基材料加工：当前形势与未来挑战

RILEM Technical Letters Pub Date : 2024-02-01 DOI: 10.21809/rilemtechlett.2023.186

Emmanuel Keita, Arnaud Perrot

{"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":null,"pages":null},"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}

引用次数: 0

Perspectives in architected infrastructure materials 架构基础设施材料的视角

RILEM Technical Letters Pub Date : 2024-01-19 DOI: 10.21809/rilemtechlett.2023.183

Reza Moini

{"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":null,"pages":null},"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}

引用次数: 0

Biomineralization in cement and concrete research 水泥和混凝土研究中的生物矿化

RILEM Technical Letters Pub Date : 2024-01-09 DOI: 10.21809/rilemtechlett.2023.187

Nicolas Dowdy, W. Srubar

{"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":null,"pages":null},"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}

引用次数: 0

A quality control framework for digital fabrication with concrete 混凝土数字制造的质量控制框架

RILEM Technical Letters Pub Date : 2023-12-05 DOI: 10.21809/rilemtechlett.2023.181

Derk Bos, Rob Wolfs

引用次数: 0

Cement and concrete decarbonisation roadmaps – a meta-analysis within the context of the United Kingdom 水泥和混凝土脱碳路线图--在英国范围内进行的元分析

RILEM Technical Letters Pub Date : 2023-11-24 DOI: 10.21809/rilemtechlett.2023.163

Alastair Marsh, Thomas Dillon, Susan A. Bernal

{"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":null,"pages":null},"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}

引用次数: 0

Thermal conductivity of porous building materials: An exploration of new challenges in fractal modelling solutions 多孔建筑材料的导热性：探索分形建模解决方案的新挑战

RILEM Technical Letters Pub Date : 2023-11-23 DOI: 10.21809/rilemtechlett.2023.178

Giorgio Pia, M. Cappai

{"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":null,"pages":null},"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}

引用次数: 0