A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
The penetration of chloride in concrete subject to wetting and drying: measurement and modelling
Corrosion of reinforcing steel arising from contamination by chlorides from de-icing salt is the major cause of deterioration of concrete bridges in the UK and many parts of the world. Those elements of structures exposed to cyclic wetting and drying (BS 8500-1, XD3) have proven to be the most vulnerable to corrosion damage. Penetration of chloride in concrete exposed to wet/dry environments occurs by diffusion and absorption. Diffusion is a relatively slow and quite well understood process. However, absorption is a relatively rapid transport mechanism and there is a lack of understanding of the role of this mechanism on chloride ingress as studies on chloride penetration in concrete exposed to wet/dry cycles ignore the effect of this mechanism on chloride ingress. In addition, chloride penetration prediction models are mostly based on Fick’s laws of diffusion, ignoring the effect of absorption on chloride ingress. The aims of this work are: to develop a more detailed understanding of chloride penetration in concrete subjected to wet/dry cycles and identify the effect of absorption on chloride ingress; to produce reliable numerical model for chloride penetration due to this transport process; to recommend values of the minimum thickness of concrete cover to steel reinforcement relevant to this service environment or identify exposure conditions which require alternative methods of protection. The absorption test method used in this work is a cyclic regime as developed by TRL [Emerson and Butler, 1997] to represent site conditions. Concrete cubes, 100 mm³, were subjected to wet/dry cycles with the suction surface in contact with NaCl solution. Drying temperature was found to be the most critical factor influencing sorptivity and depth of chloride penetration. The salt solution concentration also had a significant effect on chloride penetration via the apparent surface chloride content. Moreover, the depth of chloride penetration was found to be proportional to the square root of exposure time. Two approaches to ...
The penetration of chloride in concrete subject to wetting and drying: measurement and modelling
Corrosion of reinforcing steel arising from contamination by chlorides from de-icing salt is the major cause of deterioration of concrete bridges in the UK and many parts of the world. Those elements of structures exposed to cyclic wetting and drying (BS 8500-1, XD3) have proven to be the most vulnerable to corrosion damage. Penetration of chloride in concrete exposed to wet/dry environments occurs by diffusion and absorption. Diffusion is a relatively slow and quite well understood process. However, absorption is a relatively rapid transport mechanism and there is a lack of understanding of the role of this mechanism on chloride ingress as studies on chloride penetration in concrete exposed to wet/dry cycles ignore the effect of this mechanism on chloride ingress. In addition, chloride penetration prediction models are mostly based on Fick’s laws of diffusion, ignoring the effect of absorption on chloride ingress. The aims of this work are: to develop a more detailed understanding of chloride penetration in concrete subjected to wet/dry cycles and identify the effect of absorption on chloride ingress; to produce reliable numerical model for chloride penetration due to this transport process; to recommend values of the minimum thickness of concrete cover to steel reinforcement relevant to this service environment or identify exposure conditions which require alternative methods of protection. The absorption test method used in this work is a cyclic regime as developed by TRL [Emerson and Butler, 1997] to represent site conditions. Concrete cubes, 100 mm³, were subjected to wet/dry cycles with the suction surface in contact with NaCl solution. Drying temperature was found to be the most critical factor influencing sorptivity and depth of chloride penetration. The salt solution concentration also had a significant effect on chloride penetration via the apparent surface chloride content. Moreover, the depth of chloride penetration was found to be proportional to the square root of exposure time. Two approaches to ...
The penetration of chloride in concrete subject to wetting and drying: measurement and modelling
Bioubakhsh, S. (author)
2011-04-28
Doctoral thesis, UCL (University College London).
Theses
Electronic Resource
English
DDC:
690
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Chloride penetration in concrete exposed to cyclic drying-wetting and carbonation
| British Library Online Contents | 2016
Chloride penetration in concrete exposed to cyclic drying-wetting and carbonation
| British Library Online Contents | 2016