| 51. |
- Persson, Bertil, et al.
(author)
-
Early basic creep of high-strength concrete
- 1993
-
In: Utilization of high strength concrete : proceedings / Symposium in Lillehammer, Norway, June 20-23, 1993. - 8291341001 ; 2, s. 1185-1192
-
Conference paper (other academic/artistic)
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| 52. |
- Persson, Bertil
(author)
-
Effect of Cement Type, Silica Fume, Water-cement Ratio, Age and Moderate Shift in Temperature on Self-desiccation in Concrete.
- 1999
-
In: Nordic Concrete Research. - 0800-6377. ; 22, s. 97-114
-
Journal article (peer-reviewed)abstract
- This article outlines an experimental and numerical study on the effect of cement type, silica fume, w/c, age and moderate shift of temperature on self-desiccation and strength of concrete. For this purpose 81 sealed cylinders made of 9 concretes with w/c varying between 0.32 and 0.50, based on two types of Portland Cement, were manufactured. Five per cent silica fume was used in one third of the concretes as calculated on the basis of the cement content. Self-desiccation was studied after sealed curing at three different temperatures. The measurement was done at 1 and 6 months’ age at three temperatures. The results indicated high influence of w/c, age and cement type on self-desiccation. The influence of a moderate variation in temperature or of silica fume was insignificant. The study was performed at Lund Institute of Technology 1997-1998.
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| 53. |
- Persson, Bertil
(author)
-
Effect of silica fume on self-desiccation and strength
- 1996
-
In: Proceedings Nordic Concrete Research Meeting, Espoo, Finland 1996 / NCR Research projects 1996. - 0800-6377. - 8291341028 ; , s. 128-130
-
Conference paper (other academic/artistic)abstract
- Self-desiccation occurs in all types of concrete due to the chemical shrinkage that takes place when water is attached to the cement. In High Performance Concrete the low porosity makes the effect of self-desiccation much more pronounced. This paper presents a summary of a Nordic Seminar on Self-Desiccation in Concrete held in Lund. For this purpose aspects of mix design, curing conditions, desiccation, micro-cracking, self-stresses, shrinkage and frost resistance related to self-desiccation are detailed. Initially a background is given on the principal effects of Seminar took place in Lund on 10 June 1997.
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| 54. |
- Persson, Bertil
(author)
-
Eight-Year Exploration of Shrinkage in High-Performance Concrete.
- 2002
-
In: Cement and Concrete Research. - 0008-8846. ; 32:8, s. 1229-1237
-
Journal article (peer-reviewed)abstract
- In this paper an experimental and analytical exploration on the effect of water-binder ratio (w/b), silica fume and age on autogenous, carbonation, drying and total shrinkage of High-Performance Concrete (HPC) is outlined. Eight types of HPC were studied. Carbonation, internal relative humidity (RH) and strength were studied on specimens from the same batch of HPC that was used in the studies of shrinkage. The results indicate fairly good correlation between carbonation, shrinkage, w/b and RH. The type and amount of silica fume affected shrinkage.
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| 55. |
- Persson, Bertil
(author)
-
En fuktfri platta på mark
- 1991
-
In: Cementa. - 0346-8771. ; :1, s. 11-13
-
Journal article (other academic/artistic)
|
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| 56. |
|
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| 57. |
- Persson, Bertil
(author)
-
Experimental Studies on Shrinkage of High-Performance Concrete
- 1998
-
In: Cement and Concrete Research. - 0008-8846. ; 28:7, s. 1023-1036
-
Journal article (peer-reviewed)abstract
- This article outlines experimental and numerical studies on shrinkage of High-Performance Concrete, HPC. Especially carbonation shrinkage may introduce surface cracking in concrete, which affects the durability. In order to study shrinkage, cylinders of eight qualities of HPC were investigated. Parallel studies on autogenous shrinkage, drying shrinkage, hydration, internal relative humidity and strength were carried out. Previous research in the field is summed up. Mechanisms of carbonation shrinkage by modeling correlations to the composition of the HPC and the physical properties are presented. The results indicate that carbonation shrinkage may be avoided by addition of silica fume. The project was carried out 1992 through 1996.
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| 58. |
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| 59. |
|
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| 60. |
- Persson, Bertil
(author)
-
Fire resistance of self-compacting concrete, SCC
- 2004
-
In: Materials and Structures. - 1359-5997. ; 37:9, s. 575-584
-
Journal article (peer-reviewed)abstract
- This article outlines laboratory and full-scale studies on fire resistance of SCC. For this purpose 40 pre-stressed columns and 140 cylinders of concrete were subjected to compressive loading at high temperature. The SCC included water-binder ratios, w/b, between 0.40 and 0.70 and large amount limestone powder. Comparison was done with vibrated concrete, VC, with the same w/b. Mix proportions were chosen as regards tunnel concrete (w/b = 0.40), prefabricated concrete (w/b = 0.55) and concrete for production of dwelling houses (w/b = 0.70). The water-powder ratio, w/p varied between 0.28 and 0.70. The fullscale behaviour showed extensive fire spalling for water-cured concrete at w/p < 0.40 and for air-cured concrete at w/p < 0.35. One way of avoiding the fire spalling was to introduce polypropylene fibres, PPF, in the mix proportions, which was chosen to be very effective. The laboratory results on small cylinders indicated similar material behaviour of SCC and VC at high temperature when spalling did not occur. The project was performed 1999-2002.
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