| 1. |
- Al-Ayish, Nadia, et al.
(författare)
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Environmental impact of concrete structures reinforced with GFRP bars : A simplified study on columns
- 2019
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Ingår i: Proceedings of the fib Symposium 2019. - : International Federation for Structural Concrete. - 9782940643004 ; , s. 1998-2005
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Konferensbidrag (refereegranskat)abstract
- Concrete has a significant influence on the global warming due to its high usage in the construction industry. There are a few different strategies to increase the sustainability potential of concrete structures. Most of these strategies involve reduction of the total clinker content. One strategy, which is often neglected due to its complexity, is to increase the durability of the concrete structure. By increasing the durability, the need for repair and maintenance is reduced and thus less resources are consumed during the service life. One of the main deterioration mechanisms in concrete structures is the corrosion of steel reinforcement. A strategy to increase the service life of concrete structures in harsh environment would therefore be to increase the durability of concrete or to use low- or non-corrosive reinforcement instead of traditional steel reinforcement. This paper focuses on the latter. Glass fibre reinforced polymer (GFRP) bars are non-corrosive and have emerged as an alternative to steel bars in reinforced concrete structures in harsh environment. They have other mechanical properties than steel and opens for alternative mix designs for concrete. However, the environmental impact of concrete structures reinforced with GFRP bars has not been fully investigated and most life-cycle assessment (LCA) studies have an exchange ratio of 1:1 between GFRP and steel bars despite differences in the mechanical properties. This paper studies the climate impact of concrete columns reinforced with GFRP bars through an LCA methodology, focusing on the functional unit.
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| 2. |
- Al-Ayish, Nadia
(författare)
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Environmental Impact of Concrete Structures - with Focus on Durability and Resource Efficiency
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Concrete is essential for the construction industry with characteristic properties that make it irreplaceable in some aspects. However, due to the large volumes consumed and the energy intense cement clinker production it also has a notable climate impact. In order to reach the international and national sustainability goals it is therefore important to reduce the climate impact of concrete structures.There are many ways to influence the environmental impact of concrete and a detailed analysis is one of the actions that could push the industry and the society towards a sustainable development. The purpose of this research is to evaluate the environmental impact of concrete structures and the built environment and to highlight the possibilities to reduce that impact with choice of concrete mix and innovative design solutions.A life cycle assessment (LCA) was carried out to analyze the environmental impact of two thin façade solutions with innovative materials and to evaluate influences of different greenhouse gas reducing measures on concrete bridges. The influence of supplementary cementitious materials (SCM) in terms of climate impact and durability was also analyzed.The results indicate that SCMs have a twofold effect on the climate impact of reinforced concrete structures. Not only do they reduce the greenhouse gases through cement clinker replacement but also by an improvement of durability regarding chloride ingress. Currently, this is not considered in the regulations, which makes it difficult to foresee in LCA at early design stages. The results also show great possibilities to reduce the climate impact through different measures and design alternatives and the need for further development of products and solutions.
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| 3. |
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| 4. |
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| 5. |
- Al-Ayish, Nadia, et al.
(författare)
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The influence of supplementary cementitious materials on climate impact of concrete bridges exposed to chlorides
- 2018
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Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618 .- 1879-0526. ; 188, s. 391-398
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Tidskriftsartikel (refereegranskat)abstract
- In order to reach a specific service life of reinforced concrete structures a certain cover thickness is needed. At present, this is regulated by national standards that also limit the amount and type of supplementary cementitious materials in different exposure environments. The regulations do not, however, consider the actual durability performance of concrete with supplementary cementitious materials. As a consequence, the LCA results might be misleading. This paper shows the environmental impact of concrete with supplementary cementitious materials in chloride environment considering their specific performances. Prescriptive and performance based service life prediction models for chloride ingress are applied and compared.
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| 6. |
- Björk, Folke, 1958-, et al.
(författare)
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Simhallar – ett övergripande perspektiv på teknik, hälsa, beständighet och ekonomi
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Simhallar har olika problem, avseende både hälsoaspekter och beständighet. Dessutom förbrukar simhallar stora resurser ur ett ekonomiskt perspektiv. Neris-projektet har skaffat sig ett helikopterperspektiv på simhallars olika delar och risker och många av dessa risker orsakas av desinfektionen av badvattnet. I dagsläget så syftar hygien, rengöring och desinfektion främst till att hålla mikroorganismer på låga nivåer och det är viktigt att hygienen samt rengöringen optimeras. När det gäller desinfektionen av badvattnet så har klorering används under mycket lång tid, metoden är mycket effektiv för att döda de flesta mikroorganismerna, men orsakar även lungbesvär och korrosion som förkortar hallarnas livslängd.Denna rapport har inte hittat några vetenskapliga artiklar som belägger vilka kloreringsnivåer som bör tillämpas i en simhall. Dessa nivåer förefaller basera sig på tradition och på ett kunskapsläge då lungbesvär och korrosion inte beaktades. Det är tveksamt om exempelvis Folkhälsomyndighetens gränsvärden för klorhalter är grundade på ett spårbart sätt i vetenskapliga arbeten, som de bör vara.Det vore önskvärt att vetenskapligt undersöka vilka klornivåer som är tillräckliga och göra en sammansatt optimering med avseende på mikroorganismer, lungbesvär och korrosion.Blått ljus i simhall och fotokatalys i reningsverk reducerar behovet av klorering, vilket har visats i Enskedehallens babysim. Vidare är det möjligt att få en bättre beskrivning av den mikrobiella situationen i badvatten med hjälp av partikelmätning, vilket kan minska de bakteriella riskerna i en simhall. Dessa metoder bör bli föremål för vidare forskning.Hur stor är den sammanlagda korrosiviteten i en simhallsbyggnad? Det finns olika faktorer som samverkar i en simhall, som hög temperatur, högt fuktinnehåll i luften, klorider, underklorsyrlighet, och säkert fler faktorer, som inte är identifierade. Det är en forskningsuppgift att utföra olika metodtester för de olika delarnas korrosiva del och samverkande korrosivitet. Det finns inga rutiner för att avlägsna klorider som hamnat i simhallsrummet. Det vore bra att utarbeta sådana rutiner. Det kan finnas ett motsatsförhållande mellan beständighet och energibesparing. Exempelvis så sparas energi om ett minimum av vatten blöder av, men detta ökar kloridkoncentrationen i badvattnet. På samma sätt ökas kloridkoncentrationen i simhallsbyggnaden om luften får gå i rundgång med ökad korrosionsrisk som följd.Avdunstningen är mycket energikrävande och det vore då intressant att minimera ventilationen över vattenytan. Den ventilationen är i dagsläget behövlig för att få bort skadliga gaser, exempelvis kloroform och trikloramin, som är en följd av kloreringen. Om klorering kan minska så kan även ventilationen över vattenytan minimeras, med energibesparing som följdSimhallsprojektet i Stad x riskerar att bli mellan 50 och 100 miljoner dyrare än vad som beräknades i förstudien. Förstudien har visat sig att vara optimistisk med avseende på fördelar, men svag med avseende på kostnader. Detta har försatt staden i en ekonomisk knipa, som riskerar att exempelvis materialval blir sämre med kortare beständighet som följd.. Förstudier inför ett simhallsbygge kan bli bättre. Det vore till exempel bra att göra en tredjepartskontroll med avseende på intäkter och kostnader.En kommun skulle kunna etablera en expertgrupp av kunniga tekniker och ekonomer som skulle kunna beakta och besluta över tekniska renoverings-, underhåll- och driftsfrågor. Detta vore en strategisk kunskap, som vore bra att ha in house.
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| 7. |
- Dervishaj, Arlind, et al.
(författare)
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Digital Reuse : Leveraging technology for a circular built environment
- 2023
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Buildings are major contributors to climate change. Reusing buildings and materials in a circular economy is a promising solution, but we need methods and tools to support it. Therefore, we develop digital innovations to support the reuse of concrete, a ubiquitous construction material that represents 7-8% of global C02 emissions. In this poster, we present our research progress concerning two refereed publications presented at eCAADe and EC3 & CIB W78 conferences, both published in 2023.
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| 8. |
- Dervishaj, Arlind, et al.
(författare)
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Enabling reuse of prefabricated concrete components through multiple tracking technologies and digital twins
- 2023
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Ingår i: Proceedings of the 2023 European Conference on Computing in Construction and the 40th International CIB W78 Conference. - Heraklion, Crete : European Council for Computing in Construction. ; , s. 1-8
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Konferensbidrag (refereegranskat)abstract
- Tracking of building components can be instrumental in reuse for a Circular Economy. Tracking technologies (TT) for building components can be used to identify and access information for decision-making from deconstruction to design for reuse. Prior research has mainly been concerned with single technologies, limited life cycle applicability and new construction. This study aims to explore the potential of combining multiple technologies, such as QR codes, NFC, and Bluetooth tags, with BIM to support reuse along the life cycles of prefabricated concrete components. The benefits and limitations of choices in TT are examined concerning information integration in circular construction.
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| 9. |
- Dervishaj, Arlind, et al.
(författare)
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From LCA to circular design : A comparative study of digital tools for the built environment
- 2024
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Ingår i: Resources, Conservation and Recycling. - : Elsevier BV. - 0921-3449 .- 1879-0658. ; 200, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- This paper reviews digital tools for supporting the Circular Economy (CE) in the built environment. The study provides a bibliometric analysis and focuses on computer-aided design (CAD), building information modeling (BIM), and computational plugins that can be used by practitioners. While Life Cycle Assessment (LCA) is the primary methodology for evaluating buildings' environmental performance, the study identifies tools beyond LCA, including computational methods and circularity indicators, that can support the evaluation of circular design strategies. Our review highlights limitations in tools’ functionalities, including a lack of representative data for LCA and underdeveloped circularity indicators. The paper calls for further development of these tools in terms of interoperability aspects, integration of more sources of data for LCA and circularity, and possibilities for a comprehensive evaluation of design choices. Computational plugins offer greater flexibility, while BIM-LCA integrations have the potential to replace dedicated LCA software and spreadsheets. Additionally, the study identifies opportunities for novel digital methods, such as algorithms for circular design with various types of reused building elements, and sharing of digital twins and material passports. This research can inform future studies and support architects and engineers in their efforts to create a sustainable built environment.
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| 10. |
- Dervishaj, Arlind, et al.
(författare)
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Modelling Precast Concrete for a Circular Economy in the Built Environment : Level of Information Need guidelines for digital design and collaboration
- 2023
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Ingår i: eCAADe 2023. - Brussels, Graz : Graz University of Technology Faculty of Architecture. ; , s. 177-186
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Konferensbidrag (refereegranskat)abstract
- In recent years, there has been a growing interest in adopting circular approaches in the built environment, specifically reusing existing buildings or their components in new projects. To achieve this, drawings, laser scanning, photogrammetry and other techniques are used to capture data on buildings and their materials. Although previous studies have explored scan-to-BIM workflows, automation of 2D drawings to 3D models, and machine learning for identifying building components and materials, a significant gap remains in refining this data into the right level of information required for digital twins, to share information and for digital collaboration in designing for reuse. To address this gap, this paper proposes digital guidelines for reusing precast concrete based on the level of information need (LOIN) standard EN 17412-1:2020 and examines several CAD and BIM modelling strategies. These guidelines can be used to prepare digital templates that become digital twins of existing elements, develop information requirements for use cases, and facilitate data integration and sharing for a circular built environment.
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