| 1. |
- 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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| 2. |
- Al-Ayish, Nadia, et al.
(författare)
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Livslängden hos betongbroar: Erfarenheter och implementering med LCA/LCC
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The lifespan of construction works is crucial to achieve a low environmental impact for aprovided function. Supplementary cementitious materials are increasingly used in concrete production where the effect on the service life of structures needs to be assessed. In order to achieve a long service life, the design, flexibility in the design and workmanship also needs to be addressed.Today’s LCC and LCA analyses are based on statistics of service life of older bridges and are not material specific. There is still a lack of information about how the service life of concrete bridges is affected by different measures. The overall goal of this project was to close this information gap. The project aimed at describing key factors that affect the lifespan of concrete bridges. Key factors may reflect aspects of both durability and the utility of the design. The purpose was to investigate how the service life can be included in LCA and LCC analyses and to create a basis for future LCA and LCC analyses of concrete road bridges.Factors affecting the service life of concrete bridges have been identified through a literature survey and interviews. The studies comprised the service life of concretebridges, durability, service life models, requirements and guidelines, previous LCA and LCC studies as well as service life-extending measures throughout the whole lifecycle from material production to the end-of-life.The studies showed that reinforcement corrosion caused by chlorides is the most common cause of damage in concrete bridges where the service life of parts of theconstruction is usually shorter than the design service life. Even though frost resistance has historically been more restricting when choosing a concrete composition. The restrictions have, however, been reduced lately but there needs to be more focus on finding a design method that takes into account the impact of the concrete composition regarding reinforcement corrosion in order to find the most suitable solution for each individual case.The study shows the service life of concrete bridges depends not only on the expert’s knowledge of concrete but also on quality of execution. There is great potential to extend the service life of concrete bridges and to reduce their climate impact. However, it is important that the service life-extending measures also have a low embodied impact.The results of the survey show that technology and cost are the highest priority for mostrespondents, except for researchers where the focus is more on the environment and durability. Many also consider that contractors should set more demands towards environmentally friendly solutions.The results are compiled in the form of recommendations for reduced environmental impact and costs, as well as for how an LCA and LCC can be carried out with regard to service life.
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| 3. |
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| 4. |
- 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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| 5. |
- During, Otto
(författare)
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Betongens livscykel
- 2013
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Ingår i: CBI-nytt. - 0349-2060. ; :2, s. 4-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 6. |
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| 7. |
- During, Otto, et al.
(författare)
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Life cycle cost analysis on impregnated bridge edge beams
- 2014
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Ingår i: Restoration of Buildings and Monuments. - 1864-7251. ; 20:6, s. 441–446-
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Tidskriftsartikel (refereegranskat)abstract
- the edge beams. However, results from this study pointed out that in most cases there is a clear economic benefit to impregnate the bridge edge beams even if it has to be repeated every 15 years.
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| 8. |
- During, Otto
(författare)
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Livscykelanalys
- 2011
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Ingår i: CBI-nytt. - 0349-2060. ; :1, s. 7-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- During, Otto
(författare)
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Några reflexioner om LCA
- 2013
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Ingår i: CBI-nytt. - 0349-2060. ; :1, s. 10-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 10. |
- During, Otto, et al.
(författare)
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Rice Husk Resource for Energy and Cementitious Products with Low CO2 contributions
- 2018
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Ingår i: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 59:2, s. 45-58
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Rice Husk Ash (RHA) is a well-known supplementary cementitious materials (SCMs) that can be used for concrete with reduced CO2 contributions. In 2016, only Nepal produced 5.2 million tonnes rice that gave about 1.14 million tonnes rice husk. The rice husk can also be used directly in a cement kiln as a fuel. This study analysis the potential CO2 reductions from three scenarios and emphasis strengths, weaknesses, opportunities and treats in the production systems for initiate a decision process with possibilities to get an industry project financed from the green climate found. The highest CO2 benefits were from rice husk used in a cement kiln were half of the yearly rice husk production in Nepal could reduce the climate impact with 808000 tonnes CO2.
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