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- Folkeson, Nicklas, 1981, et al.
(författare)
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Fireside corrosion of stainless and low alloyed steels in a waste-fired CFB boiler; The effect of adding sulphur to the fuel
- 2008
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Ingår i: Materials Science Forum. ; 595-598, s. 289-297
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Tidskriftsartikel (refereegranskat)abstract
- Corrosion field tests have been carried out in the superheater region of a commercial waste-fired 75MW CFBC boiler using air cooled probes. Exposure time was 24 and 1000 hours. The effect of adding sulphur to the fuel on the corrosion of two high alloyed steels and a low alloyed steel was studied. The fuel consisted of 50% household waste and 50% industrial waste. The exposed samples were analyzed by ESEM/EDX and XRD. Metal loss was determined after 1000 hours. Both materials suffered significant corrosion in the absence of sulphur addition and the addition of sulphur to the fuel reduced corrosion significantly. The rapid corrosion of the high alloyed steel in the absence of sulphur addition is caused by the destruction of the chromium-containing protective oxide by formation of calcium chromate. Adding sulphur to the fuel inhibited chromate formation and increased the sulphate/chloride ratio in the deposit. Iron(II) chloride formed on the low alloyed steel regardless of whether sulphur was added or not.
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| 3. |
- Emborg, Mats, et al.
(författare)
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Designing robust SCC for industrial construction with cast in place concrete
- 2005
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Ingår i: Second North American Conference on the Design and Use of Self-Consolidating Concrete [and] Fourth International RILEM Symposium on Self-Compacting Concrete; [October 30 - November 2, 2005];Second North American Conference on the Design and Use of Self-Consolidating Concrete [and] Fourth International RILEM Symposium on Self-Compacting Concrete; [October 30 - November 2, 2005. - Hanley Wood. ; , s. 1251-1257
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Konferensbidrag (refereegranskat)
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| 4. |
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| 5. |
- Jonasson, Jan-Erik
(författare)
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A study of time-dependent deformations in modern concrete
- 2009
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Ingår i: Creep, shrinkage and durability of concrete and concrete structures. - Boca Raton : CRC Press, Taylor & Francis Group. - 9780415485081 ; , s. 1477-1481
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Konferensbidrag (refereegranskat)abstract
- If we consider modem concrete structures subjected to severe environment or severe loading, dense concretes are often used. Hereby, two important features are creep and shrinkage that have paramount importance for serviceability, durability, and long-term reliability of structures. This paper presents new models for the prediction of creep and shrinkage deformations in dense concrete structures. The formulas presented have been applied as modifications on the approach of CEB-FIP Model Code aimed for more open concrete structures. Such a procedure makes the framework well known to designers
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| 6. |
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| 7. |
- Jonasson, Jan-Erik, et al.
(författare)
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Beräkning av uttorkning för betong med Byggcement
- 2006
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Ingår i: Bygg och Teknik. - 0281-658X .- 2002-8350. ; :7, s. 56-
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- I sortimentet av cement från Cementa AB byttes för några år sedan standard portlandcement ut mot Byggcementet. I utvecklingen av den nya cementet eftersträvades att det skulle ha egenskaper mycket lika med det utgående standard portlandcementet. Formellt blev nu cementet ett blancement (portlandcement, CEM II), eftersom det innehåller en viss mängd finmalt kalkfiller. Dessutom har portlandklinkern en någon större finmaldhet (större specifik yta) än i det äldre portlandcementet.
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| 9. |
- Jonasson, Jan-Erik, et al.
(författare)
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Gjutning av vägg på platta : studier av sprickrisker orsakat av temperaturförloppet vid härdningen
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Tests casting the construction "wall on slab" have in the project been realized for three different situations. Measurements have been performed with respect to temperatures, deformations, strains and mapping of crack patterns. In addition, properties for the young concrete have been investigated to get basic data in order to estimate temperatures and risks of cracking. The construction wall on slab represents a typical case, which can be found in many real structures like walls, retaining walls, tray structures, tunnels and bridges.The project has two main questions: 1) What are the differences in restraint conditions between the three tested constructions? Is it correct to model a wall, that both has a horizontal casting joints against the slab, and a vertical casting joint against an adjacent wall, with a free wall of double length?, and 2) Does a slip in the horizontal casting joint exist, and does is reduce the restraint in the wall?The answers are that the supposed models describe the real behaviour very well. This was confirmed by the fact that both the temperatures as well as the crack risks agreed very well between the test results and the calculation results. For the walls that cracked a slip in the casting joints could be indicated, but these test results could not be quantified. In summary, the project has been successful and clearly answered questions that previously only were based on assumptions.
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| 10. |
- Jonasson, Jan-Erik, et al.
(författare)
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How to build crack-free durable concrete structures : concrete hardening technology including modelling of shrinkage, creep and temperature of young concrete and its influence on durability and lifetime
- 2009
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Ingår i: ISLECI 2009. - : Central South University of Forestry and Technology, China.
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Konferensbidrag (refereegranskat)abstract
- Control of thermal and shrinkage cracking in hardening concrete is of great importance to ensure desired service life and function of concrete infrastructures. Making reliable stress estimations, and thereby conclusions about cracking risks caused by temperature movements and shrinkage involves advanced modelling of material properties and structural restraint. The paper presents the main outline of a model for description of material properties needed. Special focus is given to a creep model denoted LLM (Linear Logarithmic Model), which is shown to be robust, easy to use, and capable to extrapolate short-term test into long-term effects. Applications of the presented model using the computer program ConTeSt Pro demonstrates that it can be used to decide what measures to be taken to minimize the risk of cracking during the hardening phase for concrete structures.
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