Time-dependent chloride transport models for predicting service life of bridge decks under chloride attack

2021 ◽  
Author(s):  
Uthairith Rochanavibhata ◽  
Koonnamas Punthutaecha ◽  
Aruz Petcherdchoo
Keyword(s):  
Service Life ◽  
Chloride Transport ◽  
Bridge Decks ◽  
Time Dependent ◽  
Transport Models ◽  
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.

Kapillares Eindringen von Wasser und Salzlösungen in Beton / Penetration of Water and Salt Solutions into Concrete by Capillary Suction

1998 ◽  
Vol 4 (4) ◽  
pp. 399-422 ◽  
Author(s):  
P. Lunk
Keyword(s):  
Spatial Distribution ◽  
Service Life ◽  
Chloride Transport ◽  
Dominant Role ◽  
Time Dependent ◽  
Capillary Absorption ◽  
Salt Solutions ◽  
Back Wall ◽  
Capillary Suction ◽  
Retardation Coefficient

Abstract Capillary suction plays a dominant role in the ingress of chlorides and therefore in the durability of concrete. The capillary absorption of fluids into concrete is analysed in terms of a simple capillary-model. With the help of this model and under given conditions, the water and chloride transport by capillary suction can be described in a realistic way. The fundamental influences of different parameters such as porosity, pore size distribution, moisture content and interaction between fluid and concrete are outlined. The retardation effect as regards capillary chloride transport ('Huckepack-Transport') is characterised by a retardation coefficient. The calculation of time-dependent spatial distribution of water and chloride allows the durability of different concrete grade to be predicted. Here, the service life of the back wall of a rehabilitated avalanche-gallery is calculated under defined requirements.

Environmental Impact due to Repairs by Surface Treatment on Concrete Structures Exposed to Chloride Environment

2016 ◽  
Vol 711 ◽  
pp. 974-981
Author(s):  
Aruz Petcherdchoo ◽  
Chotima Ongsopapong
Keyword(s):  
Diffusion Coefficient ◽  
Environmental Impact ◽  
Service Life ◽  
Surface Treatment ◽  
Time Dependent ◽  
Life Extension ◽  
Free Service ◽  
Before And After ◽  
Chloride Attack ◽  
Service Life Extension

This paper presents the environmental impact in terms of CO2 and service life extension due to repairs by surface treatment on concrete structures exposed to time-dependent chloride attack. The service life extension is defined as the difference between the corrosion-free service life of concrete before and after surface treatment by silanes. The corrosion-free service life is predicted based on considering the mechanism of chloride diffusion which can be described using the partial differential equation (PDE) of the Fick’s second law. With the surface treatment, solving the PDE is complicated due to non-constant diffusion coefficient. Furthermore, if the diffusion coefficient is time-dependent, it is even more complicated to solve the PDE. Therefore, numerical computation by the Crank-Nicolson based finite difference method is introduced as a computational tool. From computation, the chloride profiles before and after different surface treatment strategies can be calculated considering time-dependent chloride attack. Furthermore, the environmental impact in terms of CO2 due to surface treatment is also presented. Finally, numerical examples to calculate the service life extension after surface treatments and the environmental impacts are compared.

The Effect of Cracks on Chloride Penetration into Concrete

2007 ◽  
Vol 348-349 ◽  
pp. 769-772 ◽  
Author(s):  
In Seok Yoon ◽  
Erik Schlangen ◽  
Mario R. de Rooij ◽  
Klaas van Breugel
Keyword(s):  
Service Life ◽  
Crack Length ◽  
Significant Influence ◽  
Crack Width ◽  
Chloride Transport ◽  
Crack Depth ◽  
Chloride Penetration ◽  
Critical Crack ◽  
Chloride Migration ◽  
Migration Testing

This study is focused on examining the effect of critical crack width in combination with crack depth on chloride penetration into concrete. Because concrete structures have to meet a minimum service-life, critical crack width has become an important parameter. Specimens with different crack width / crack length have been subjected to rapid chloride migration testing (RCM). The results of this study show a critical crack width of about 0.012 mm. Cracks smaller than this critical crack width are considered not to have a significant influence on the rate of chloride transport inwards, while chloride penetration does proceed faster above this critical crack width.

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.

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