| 1. |
- Bissonnette, B., et al.
(författare)
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Recommendations for the repair, the lining or the strengthening of concrete slabs or pavements with bonded cement-based material overlays
- 2013
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Ingår i: Materials and Structures. - : Springer. - 1359-5997 .- 1871-6873. ; 46:3, s. 481-494
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Tidskriftsartikel (refereegranskat)abstract
- The recommendations presented in this publication are inspired by the State of the Art Report edited by the RILEM Technical Committee TC 193 RLS Bonded cement-based material overlays for the repair, the lining or the strengthening of slabs and pavements. The objective is to lay out all the practical aspects to be considered in the design of concrete overlay.bonded concrete overlay process, assessment of the existing structure, surface preparation, overlay materials, design methods, construction procedure and quality control/assurance system, and maintenance.
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| 2. |
- Destrée, Xavier, et al.
(författare)
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Steel fibre reinforced concrete in free suspended slabs : Case study of the Swedbank Arena in stockholm
- 2012
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Ingår i: fib Symposium 2012. - 9789198009811 ; , s. 97-100
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Konferensbidrag (refereegranskat)abstract
- The total replacement of traditional rebars with steel fibres is now completely routine for 19 years in applications such as industrial and commercial suspended slabs resting on pile grids. In Stockholm, the Swedbank Arena foundation slabs have been completed according to that long successful experience. Its foundation slabs span from 3 m to 5 m each way, with span to depth ratios from 10 to 20. The foundation slab was designed according to Belgian praxis but has been compared with Swedish praxis. The steel fibre reinforced concrete (SFRC) mixes, which contain up to 50 kg/m3 of steel fibres, were also fully pumpable and did not need any poker vibrating. Significant time and material cost savings were then achieved compared with traditional reinforced concrete. Therefore SFRC enables a lean design with a better carbon footprint.
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| 3. |
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| 4. |
- 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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| 5. |
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| 7. |
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| 8. |
- Hedebratt, Jerry, et al.
(författare)
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Full-scale test of a pile supported steel fibre concrete slab
- 2014
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Ingår i: Materials and Structures. - : Springer Science and Business Media LLC. - 1359-5997 .- 1871-6873. ; 47:4, s. 647-666
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the short-term studies is to investigate the structural behaviour of pile supported slabs made of steel fibre concrete (SFC) only and combined reinforced steel fibre concrete. The studies include tests on an elevated slab where a combination of reinforcement bars and steel fibres have been used in one half of the slab and SFC only in the other half. The tests were performed on a column-supported elevated slab that simulates a half scale model of an industrial pile-supported floor slab. The short-term tests showed considerable structural and crack arresting performance that also increased with a higher dosage of fibres. A small addition of conventional reinforcement bars further increased the ultimate load capacity P (Max). P (Max) was in the range of 125-298 kN for the two types of slab. The results indicate that SFC can be used with verifiable results in structural applications for elevated slabs and pile-supported floor slabs despite that the material testing from the ordered SFC showed a larger scatter in properties and that the calculated load capacities were only 40-220 kN. Main causes of deviance are arch and membrane effects.
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| 9. |
- Hedebratt, Jerry, et al.
(författare)
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Full-Scale Test on a Pile Supported Floor Slab – Steel Fibre Concrete Only or in a Combination with Steel
- 2008
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Ph. D project “Integrated Design and Construction of Industrial Floors” proceeds after the presentation of a Licentiate thesis covering methods to increase the quality of concrete floors, Hedebratt (2004). The aim for further studies is to develop directions for design and construction of pile supported steel fibre concrete, SFC floors. SFC is common in industrial floor slabs. In pile supported floor slabs also a combination of non-tensioned reinforcing bars and steel fibres have been used. Furthermore, neither Swedish nor European or any other known design guidelines cover steel fibres as the only reinforcement in pile supported floors or structural members.A common engineering advice is to disregard the ground support. The scope is to investigate the possibility to consider steel fibre only design solutions in a safe way and to compare it with a combined solution and as a reference performing full-scale tests and to develop design guidelines. The now ongoing test on a column supported deck emulates a half scale of an industrial supported floor slab but may also be considered to be full scale of a structural mushroom floor for small housing.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Mohammadi Mohaghegh, Ali, et al.
(författare)
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An Initial Investigation of the Possibility to Use Basalt Fibres for More Durable Concrete Structures in Norwegian Fish Farming
- 2014
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Konferensbidrag (refereegranskat)abstract
- Reinforcement corrosion in concrete structures in the harsh environment of the humid and cold climate of the Norwegian west coast is one of the most challenging problems pertaining to the design and construction of marine concrete structures. Using new materials with a higher strength and durability than steel reinforcement can be a good solution in such circumstances. In our study we investigate the use of new forms of macro fibres termed MiniBars made from basalt fibres. The paper presents our preliminary findings indicating that basalt fibres might provide more sustainable reinforcement in concrete barges.
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| 14. |
- 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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| 15. |
- 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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| 16. |
- Silfwerbrand, Johan L.
(författare)
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Improving preventive bridge maintenance
- 2010
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Ingår i: Recent advances in maintenance and repair of concrete bridges. - : American Concrete Institute. - 9781618392053 ; , s. 67-78
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Konferensbidrag (refereegranskat)abstract
- During the last decade, the Swedish Road Administration (SRA) has transferred resources from corrective to preventive bridge maintenance. Presently, 10 to 15 percent of the budget is devoted to preventive maintenance whereas corrective maintenance, repair, and reconstruction comprise the remaining 85 to 90 percent. This reallocation has resulted in considerable efficiency gains but further savings are likely to be large. Preventive maintenance aims at measures to maintain the function of the bridge structure. Frequent measures include water washing, cleaning, vegetation removal, crack repair, material refill, and stretching of bridge railings. SRA has defined a series of technical requirements to harmonize the preventive bridge maintenance. Several technical requirements state that a structural element or element part "should be 95 percent clean". SRA has also developed methods to verify that the technical requirements are fulfilled. However, the scientific basis for the relationship between the technical requirements and the function of the bridge structure is unknown or weak. The verification methods are not always unquestionable. The paper contains a critical review of the technical demands for preventive bridge maintenance in Sweden. Do they adequately promote durability and long-lasting service life? Are the prescribed requirement levels appropriate? Could the technical requirements be replaced by other and better requirements? How do they look like in an international comparison? There is a general belief that performance-specified contracts would be more cost-effective than other contract types. Do the Swedish demands facilitate or obstruct performance-specified contracts for bridge maintenance? The questions are discussed in the paper that also contains a summary of a Swedish pilot study conducted at the Swedish Cement and Concrete Research Institute.
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| 17. |
- 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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| 18. |
- Silfwerbrand, Johan L., et al.
(författare)
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Reducing Crack Risk in Industrial Concrete Floors
- 2014
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Ingår i: ACI Materials Journal. - : American Concrete Institute. - 0889-325X .- 1944-737X. ; 111:6, s. 681-689
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Tidskriftsartikel (refereegranskat)abstract
- Cracking and curling are two important problems in industrial concrete floors. In many practical cases, it is easier to design the concrete floor slab for mechanical loads than for shrinkage stresses. This paper proposes a simple equation that mirrors the major factors influencing the crack risk in concrete floor slabs. By using this equation, the industrial floor designer or contractor can make a proper material selection that leads to a substantially reduced crack risk. Tests on strength, free shrinkage, restrained shrinkage, and flexural creep support this hypothesis. Furthermore, the use of shrinkage-reducing admixtures (SRAs) seems to not only reduce the free shrinkage but also maintains the beneficial condition of substantial creep that leads to shrinkage stress reduction.
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| 19. |
- 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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| 20. |
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