| 1. |
- Gram, Annika, et al.
(författare)
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Particle motion in fluid : Analytical and Numerical Study
- 2016
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Ingår i: Applied Rheology. - : Kerschensteiner Verlag GmbH. - 1430-6395 .- 1617-8106. ; 26:2
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Tidskriftsartikel (refereegranskat)abstract
- Particle motion in fluid is discussed for one-particle systems as well as for dense suspensions, such as cementitious materials. The difference in large particle motion between larger particles and behaviour of fines (<125 μm) is explained, motion of one particle is shown by numerical simulation. It is concluded and highlighted that it is the particular motion of the fines that to a large extent contribute to the rheological properties of a suspension. It is also shown why larger ellipsoidal particles do not necessarily contribute to the increase of viscosity.
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| 2. |
- Mohammadi Mohaghegh, Ali, et al.
(författare)
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Properties of Fresh Macro Basalt Fibre (MiniBar) Self-Compacting Concrete (SCC) and Coventional Slump Concrete (CSC) Aimed for Marine Applications
- 2015
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Ingår i: Nordic Concrete Research. - Ålesund : NORSK BETONGFORENING. - 0800-6377. ; 52:1, s. 43-61
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Tidskriftsartikel (refereegranskat)abstract
- Macro basalt fibres (MiniBar) with high corrosion resistance could be a suitable material in fibre concrete for marine applications. Due to the lack of knowledge about macro basalt fibre concretes (BFCs), the main objective of this paper is to assess the fresh state properties of macro basalt fibre conventional slump concrete and self-compacting concrete as the first step of developing BFC for concrete barges for fish farming on the west coast of Norway. To satisfy the requirements for marine applications, DNV and NS-EN standard rules are employed as the basis for the durability performance design. The concrete mix is designed to achieve densely compacted matrix by using the modified Andreasen & Andersen model as the particle size distribution target. In this paper, slump, flow-ability, passing-ability, fibre dynamic segregation and also flow rate as an indication for viscosity of different BFCs are measured and analysed. The result shows that there is a possibility to produce BF-SCCs with a fibre content of 1.15%. The fibres have an aspect ratio of 65.15. In addition, the mixture composed of a maximum gravel size of 16 mm shows a higher flowability in comparison with the maximum gravel size of 12 mm.
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| 3. |
- Mohammadi Mohaghegh, Ali
(författare)
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Use of Macro Basalt Fibre Concrete for Marine Applications
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Deterioration of concrete structures due to the corrosion of embedded steel is a well-known universal problem. Norway with its numerous bridges, ports, offshore and floating structures along its coastline, is also encountered with corrosion degradation. The harsh environment of the Norwegian Sea regarding its low temperature, wind, and waves, makes the design and construction of marine structures more demanding. In recent years, usage of sustainable composite materials in the field of structural engineering has been rising. The usage of natural fibre reinforced polymer materials in the form of reinforcement bars or macro fibres with a low density, high strength, and excellent corrosion resistance, gives us better choices for the design and construction of marine structures. Our knowledge about the fibre reinforced self-compacting concrete has increased as a result of introducing it as a building material some decades ago. However, more research is still needed when it comes to the application of new types of fibres. This thesis is a result of this need, whereby the author has done two series of experimental programmes regarding the subject. In the first series, the flow characteristics of fresh state, conventional and self-compacting macro basalt fibre concrete were studied. In the second series, mechanical properties of high performance and medium strength macro basalt fibre concrete including the post-cracking behaviour, compressive strength and electrical resistivity were in focus. The findings were presented in three appended papers and the extended summary composing this thesis. Additionally, the thesis presents an overview of the design procedure of floating concrete structures and the possibility of using macro basalt fibre concrete via a case study. The author’s literature review shows that basalt fibres have an adequate resistance against alkali environment of the concrete matrix and corrosive environment of seawater.
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| 4. |
- Silfwerbrand, Johan L., et al.
(författare)
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New swedish design guide for fibre concrete structures
- 2015
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Ingår i: Concrete - Innovation and Design. - : Technical University of Denmark. ; , s. 91-92
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Konferensbidrag (refereegranskat)abstract
- Steel libre concrete was developed during the 2nd d World War with the aim to improve the energy consumption ability of concrete shelters. In Sweden, steel fibre concrete has been used in 50 years especially in two applications; shotcrete for rock strengthening and industrial floors. In spring 2014, SIS the Swedish Standards Institute published a standard on the design of fibre concrete structures. The standard may be regarded as a compliment to Eurocode 2. Additional paragraphs have been added to a number of clauses in Eurocode 2. This paper describes the most important items in the standard and discusses how it can be used in order to simplify the design and production of libre concrete structures with maintained safety level. The overall conclusion is that the new Swedish Standard will remove an obstacle that has restrained the use of fibre concrete in structural beams and slabs.
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| 5. |
- Silfwerbrand, Johan L.
(författare)
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SWEDISH VIEW OF CONCRETE AND SUSTAINABILITY
- 2016
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Ingår i: II INTERNATIONAL CONFERENCE ON CONCRETE SUSTAINABILITY - ICCS16. - 9788494507779 ; , s. 958-966
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Konferensbidrag (refereegranskat)abstract
- Being the most frequently used man-maid construction material with a history of more than 2000 years, concrete may be defined as a sustainable material per se. Correctly designed, properly constructed, and suitably maintained, a concrete structure may reach a life-span that substantially exceeds 100 years. Durability is the bases for sustainability. The importance of sustainability has increased successively during the last 20 years. In the concreteindustry, the focus has been on substituting Portland cement - that roughly stands for 5 percent of the carbon dioxide emissions globally - with various byproducts as slag, fly ash, and silica fume. However, there are many more aspects on sustainable concrete. The Swedish cement producer Cementa AB has a zero vision, i.e., there should be no CO2 emissions in 2030. The goal will be reached by making the kiln more energy efficient, replacing fissile fuels by renewable fuels, taking the carbon uptake through carbonization into account, and by developing carbon capture and storage. We may develop new concrete mixes that either are lean with not more cement than necessary or high strength that will reduce the cross section and thus the dead load considerably. In addition to all these measures on the material side, we must maximize the benefits of concrete during the serviceability state. The effects of energy storage capacity, brightness, and wear resistance make concrete buildings and concrete pavements competitive but by, e.g., increasing density, whiteness, and wear resistance we may save more energy for heating, cooling, illumination, and repaving. Finally, we must not forget concrete's opportunities concerning recycling.
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