scholarly journals Simulation Model for Deterioration of Concrete Structures due to Chloride Attack

2003 ◽  
Vol 1 (2) ◽  
pp. 139-146 ◽  
Author(s):  
Koji Takewaka ◽  
Toshinobu Yamaguchi ◽  
Satoshi Maeda
Keyword(s):  
Simulation Model ◽  
Concrete Structures ◽  
Chloride Attack

scholarly journals Sensitivity of Service Life Extension and CO2 Emission due to Repairs by Silane Treatment Applied on Concrete Structures under Time-Dependent Chloride Attack

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Aruz Petcherdchoo
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Treatment Strategies ◽  
Time Dependent ◽  
Life Extension ◽  
Silane Treatment ◽  
Application Time ◽  
Free Service ◽  
Chloride Attack ◽  
Service Life Extension

This paper presents sensitivity of service life extension and CO2 emission due to silane (alkyltriethoxysilane) treatment on concrete structures under time-dependent chloride attack. The service life is predicted by the Crank–Nicolson-based finite difference approach for avoiding the complexity in solving Fick’s second law. The complexity occurs due to time-dependent chloride attack and nonconstant diffusion coefficient of concrete with silane treatment. At the application time of silane treatment, the cumulative CO2 emission is assessed. The effectiveness of silane treatment is defined as the ratio of the service life extension to the cumulative CO2 emission assessed within the corrosion-free service life. The service life extension is defined as the difference between corrosion-free service life of concrete structures without and with time-based application of silane treatment. From the study, the diffusion of chlorides in concrete with silane treatment is found to be retarded. In comparison, the strategy without deterioration of silanes during effective duration is more suitable for service life extension but less effective than that with deterioration. In the sensitivity analysis, there are up to eight parameters to be determined. The service life of concrete structures without silane treatment is most sensitive to the water-to-cement ratio and the threshold depth of concrete structures. Considering only five parameters in silane treatment strategies, the service life is most sensitive to the first application time of silane treatment. The cumulative CO2 emission is most sensitive to either the first application time of silane treatment or the amount of CO2 emission per application.

Service Life Extension and CO2 Emission due to Silane Treatment on Chloride-Exposed Concrete Structures

2017 ◽  
Vol 728 ◽  
pp. 384-389
Author(s):  
Aruz Petcherdchoo ◽  
Chotima Ongsopapong
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Treatment Strategies ◽  
Life Extension ◽  
Chloride Diffusion ◽  
Silane Treatment ◽  
Free Service ◽  
Before And After ◽  
Chloride Attack ◽  
Service Life Extension

This study presents assessment of the environmental impact in terms of the CO2 due to silane treatment for extending corrosion-free service life of concrete structures under chloride attack. To achieve this, there are two issues to be addressed; prediction of corrosion-free service life extension, and assessment of the amount of CO2 emission. In predicting the corrosion-free service life extension, the behaviors of chloride diffusion before and after time-based silane treatment are considered. Then, the cumulative CO2 due to silane treatment is accordingly calculated. The ratio of the corrosion-free service life extension to the cumulative CO2 is defined as the effectiveness of silane treatment, and used to compare different silane treatment strategies.

scholarly journals Evaluation of Chloride-Ion Diffusion Characteristics of Wave Power Marine Concrete Structures

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5675
Author(s):  
Changhyuck Lim ◽  
Gyuyong Kim ◽  
Gyeongtae Kim ◽  
Bokyeong Lee ◽  
Youngduck Kim ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Atmospheric Pressure ◽  
Concrete Structures ◽  
Chloride Ion ◽  
Wave Power ◽  
Ion Diffusion ◽  
Chloride Ion Penetration ◽  
Chloride Attack ◽  
Marine Concrete ◽  
Chloride Ion Diffusion

Wave power marine concrete structures generate electrical energy using waves. They are exposed to a multi-deterioration environment because of air and hydrostatic pressure and chloride attack. In this study, the effect of air pressure repeatedly generated by water level change of wave power marine concrete structures on the chloride-ion diffusion of marine concrete was analyzed. The chloride-ion diffusion of wave power marine concrete structures was evaluated. The results show that the air chamber and bypass room, which were subjected to repetitive air pressures caused by water level changes, showed a higher water-soluble chloride-ion content compared to the generator room and docking facility, which were subjected to atmospheric pressure. Field exposure tests and indoor chloride attack tests were performed using fabricated specimens to analyze the effect of pressure on chloride-ion penetration. It was confirmed that Portland blast furnace slag had a greater inhibitory effect on chloride-ion penetration than ordinary Portland cement. The concrete specimens subjected to pressure showed increased capillary pores and micro-cracks. We devised an equation for calculating the diffusion coefficient based on measured data and estimating the diffusion coefficient for the location receiving repeated air pressure by using the diffusion coefficient of the location receiving general atmospheric pressure.

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