1,721,019 research outputs found
State-of-the-Art Review of Capabilities and Limitations of Polymer and Glass Fibers Used for Fiber-Reinforced Concrete
Get PDFThe concrete industry has long been adding discrete fibers to cementitious materials to compensate for their (relatively) low tensile strengths and control possible cracks. Extensive past studies have identified effective strategies to mix and utilize the discrete fibers, but as the fiber material properties advance, so do the properties of the cementitious composites made with them. Thus, it is critical to have a state-of-the-art understanding of not only the effects of individual fiber types on various properties of concrete, but also how those properties are influenced by changing the fiber type. For this purpose, the current study provides a detailed review of the relevant literature pertaining to different fiber types considered for fiber-reinforced concrete (FRC) applications with a focus on their capabilities, limitations, common uses, and most recent advances. To achieve this goal, the main fiber properties that are influential on the characteristics of cementitious composites in the fresh and hardened states are first investigated. The study is then extended to the stability of the identified fibers in alkaline environments and how they bond with cementitious matrices. The effects of fiber type on the workability, pre- and post-peak mechanical properties, shrinkage, and extreme temperature resistance of the FRC are explored as well. In offering holistic comparisons, the outcome of this study provides a comprehensive guide to properly choose and utilize the benefits of fibers in concrete, facilitating an informed design of various FRC products.This article is published as Shafei, Behrouz, Maziar Kazemian, Michael Dopko, and Meysam Najimi. "State-of-the-art review of capabilities and limitations of polymer and glass fibers used for fiber-reinforced concrete." Materials 14, no. 2 (2021): 409. doi: https://doi.org/10.3390/ma14020409. © 2021 by the authors. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)
Suitability of Excavation Clay Wastes for Sustainable Earthen Construction
No full textAchieving net-zero emissions by 2050 is driving innovation across the construction industry. Within the industry, there is no component in greater need for change than concrete. The carbon emissions associated with concrete production could be reduced if radical changes to the industry took place. Calcined clay is a growing area of research interest, with its value in LC3 concrete showing great potential. Research beyond concrete-based applications, however, is sparse. This chapter will review the reactivity of calcined clays and assess their suitability as pozzolanic materials. The high reactivity potential of kaolinite is well established across literature; however, the reactivity of low-grade excavation waste comprising 2:1 clay minerals is underexplored. This study thereby assesses the chemical properties and reactivity potential of waste clays and therefore their potential as a polymer. Isothermal calorimetry and bound water R3 tests confirmed that certain excavation wastes exhibit similarities to pure 2:1 minerals like bentonite. While kaolinite is preferred, moderate to high proportions of 2:1 minerals demonstrate potential as supplementary cementitious materials. The novelty of this research is that pozzolanic waste will be applied within earth, rather than concrete. The lower strength requirements of earthen structures alongside typically poor durability properties will be examined in future studies. This study of chemical performance within earthen applications will further demonstrate the value of calcined clay, an abundant yet low-carbon material, thereby facilitating the industry’s transition towards net-zero.</p
SirkTRE’s Evolution or Circulution?:Diverse Pathways of Circular Systemic Solutions for a Net-Zero Timber-Built Environment
No full textThe Norwegian innovation and action project SirkTRE is halfway through. In recent years, it has been increasingly recognized that circular wood solutions for construction solutions are often technically feasible; this is particularly underscored by the SirkTRE project (2022–2025). However, the scaling up of these solutions and their interaction with various barriers underscore the necessity of systemic approaches. This chapter delves into selected circular systemic solutions derived from the project. This collaborative autoethnography, drawing insights from observations and reflections on own experiences, takes an evolutionary approach to selected SirkTRE solutions. The case studies within SirkTRE include solutions at the manufacturing level, the architectural product-system level, and the building-site level and strategies engaging municipalities to supply and utilize reclaimed timber in (especially public) buildings. These examples illustrate not only the successes but also the challenges, including how economic, political, technological, and strategic decisions can impact the scaling up/out or ending. To catalyze a true revolution, or ‘circulution’, it is imperative to integrate governance, and business models, to foster interactions in the emerging system
Exploring the Predictive Performance of Simple Regression Models and ANN in 2D Truss Analysis
Get PDFThis research investigates the performance of various regression models in predicting critical structural parameters within a plane truss model. The study encompasses linear, second- and third-degree polynomial, and artificial neural network (ANN) regression models, which are evaluated for their accuracy in estimating the maximum displacement, maximum (tensile) stress, and minimum (compressive) stress of the truss under specific loading conditions. The findings unequivocally establish the superiority of the ANN model, showcasing its ability to capture complex nonlinear relationships within the data. Moreover, the research explores the influence of model complexity, demonstrating that the transition from simpler to more intricate models enhances predictive performance. The implications of this study extend to diverse engineering applications, offering insights into the selection of appropriate regression models for structural analysis and design. Beyond improved predictive accuracy, the ANN’s predictions provide potential for reducing computational demands, making them valuable tools in structural optimization and similar contexts. However, the study underscores the importance of cautious interpretation, as certain scenarios may yield outlier predictions. Overall, this research contributes to the understanding of regression modeling in engineering and provides a foundation for informed decision-making in structural analysis and design
Advancing Sustainable Construction Materials: Wood and Rubber Geopolymer Masonry Mix Development
Get PDFRecycling industrial waste into construction materials is becoming a fundamental strategy, offering a hopeful path toward sustainable construction practices. This study focuses on the innovative reuse of end-of-service wood and crumb rubber to develop environmentally favorable materials. Their high availability, lightweight properties, and high-energy absorption capacity make them highly suitable as additives in masonry unit production. Furthermore, using them with sustainable binding material, such as geopolymer, enhances the overall sustainability of the masonry, facilitating rapid strength development and enhancing durability while providing increased protection against fire and weathering. The study involved the development of an optimal mix design, which can potentially be used for the production of load-bearing and non-load-bearing masonry units. This was achieved by examining various proportions of wood, as well as combinations of wood and rubber, using a partial–factorial experimental design. The results show that wood-to-binder ratios ranging from 0.2 to 0.4 can potentially be used for the production of wood–geopolymer masonry units. Additionally, a ratio of 0.3 (with 50% wood and 50% rubber) was identified as potentially suitable for producing wood and rubber-based units
Urban Waste Recycling: A Multi-objective Approach for Sustainable Construction in European Regions
No full textISSN:2366-2557ISSN:2366-2565ISSN:2366-256
The 1st International Conference on Net-Zero Built Environment
No full textThis open access book provides the latest fundamental and practical advances in reducing the built environment’s carbon footprint based on a collection of papers presented at the 1st International Conference on Net-Zero Built Environment: Innovations in Materials, Structures, and Management Practices, held June 19-21, 2024, in Oslo, Norway. The volume presents research investigations and case studies spanning five interrelated domains: New materials and material preparation processes for zero (or negative) carbon footprint Robotic construction technologies for minimum formwork and on-site activities Novel structural designs and details for optimal performance with the least material usage Advanced condition assessment and health monitoring methods for the longest service life Innovative life-cycle analysis and policy-making strategies for effective civil infrastructure managemen
Compressive Strength Gain of Glass Powder–Portlandite:An Investigation Toward Maximizing the Use of Waste Glass as Cement Replacement in Concrete
Get PDFThe paper presents selected findings from a combined theoretical and experimental investigation focusing on chemical reactions and strength gain in glass powder (GP) and calcium hydroxide (CH) mixes as a means of achieving more than the current wisdom of ~20% cement replacement with waste glass powder in concrete. The expected chemical reactions between CH (in concrete, CH is available as a by-product of cement hydration) and silica (SiO2) present in GP were first theoretically established using mole concept theory. The theoretically obtained results were then used to determine an appropriate CH and GP mix ratio for the CH–GP test specimens. The strength gain in CH–GP specimens with time was determined using compression tests, and the formation of strength contributing compound calcium–silicate–hydrate (C–S–H) was determined using X-ray diffraction (XRD) experiments. The compression test results showed CH–GP specimens possessed noticeable compressive strength, and the XRD results confirmed the formation of C–S–H. The results of both compression test and XRD analysis show the major strength imparting compounds in CH–GP specimens formed at later stages (i.e., after 28 days) of curing
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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