Time dependent models of apparent diffusion coefficient and surface chloride for chloride transport in fly ash concrete

Petcherdchoo, Aruz

doi:10.1016/j.conbuildmat.2012.08.041

Cited by 149 publications

(44 citation statements)

References 16 publications

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“…The calculation is simple and convenient and, in addition, the values of parameters C s and D a can be easily estimated from experimental or field data using regression analysis. However, this model has limitations when applied to concrete [13][14][15] and a number of modifications have been proposed to account for the time-dependency of these parameters through aging factors, some of which are presented in Table 1 [16][17][18][19][20][21][22][23][24]. As the factors applied on C s and D a , are determined empirically they can vary within wide limits [25][26][27][28].…”

Section: Empirical (Fickian) Model Based On the Erfc Functionmentioning

confidence: 99%

Chloride ingress into marine exposed concrete: A comparison of empirical- and physically- based models

Kim

McCarter

Suryanto

et al. 2016

Cement and Concrete Composites

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT AbstractIn establishing the reliability of performance-related design methods for concrete -which are relevant for resistance against chloride-induced corrosion -long-term experience of local materials and practices and detailed knowledge of the ambient and local micro-climate are critical. Furthermore, in the development of analytical models for performance-based design, calibration against test data representative of actual conditions in practice is required. To this end, the current study presents results from full-scale, concrete pier-stems under long-term exposure to a marine environment with work focussing on XS2 (below mid-tide level) in which the concrete is regarded as fully saturated and XS3 (tidal, splash and spray) in which the concrete is in an unsaturated condition. These exposures represent zones where concrete structures are most susceptible to ionic ingress and deterioration. Chloride profiles and chloride transport behaviour are studied using both an empirical model (erfc function) and a physical model (ClinConc). The time dependency of surface chloride concentration (C s ) and apparent diffusivity (D a ) were established for the empirical model whereas, in the ClinConc model (originally based on saturated concrete), two new environmental factors were introduced for the XS3 environmental exposure zone. Although the XS3 is considered as one environmental exposure zone according to BS EN 206-1:2013, the work has highlighted that even within this zone, significant changes in chloride ingress are evident. This study aims to update the parameters of both models for predicting the long term transport behaviour of concrete subjected to environmental exposure classes XS2 and XS3.Keywords: concrete, full-scale testing, marine environment, modelling, durability, IntroductionThe most predominant process associated with reinforced concrete deterioration is the ingress of water contaminated with chloride either from deicing salt used for snow and ice control on roads for winter maintenance purposes or from the marine environment where, for example, bridges span tidal estuaries. Because the use of deicing salt is likely to continue for the foreseeable future, and concrete structures will always be placed in, or near, the marine environment, little can be done to prevent structures from being exposed to chloride salts.The premature deterioration of concrete structures due to chloride ingress and subsequent corrosion of the steel reinforcement is a world-wide problem and imparts a significant drain...

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Section: Empirical (Fickian) Model Based On the Erfc Functionmentioning

confidence: 99%

Chloride ingress into marine exposed concrete: A comparison of empirical- and physically- based models

Kim

McCarter

Suryanto

et al. 2016

Cement and Concrete Composites

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“…Furthermore, three benchmark examples were performed to verify both the accuracy and efficiency. Petcherdchoo (2013) developed a chloride transport model mathematically consistent with time-dependent apparent diffusion coefficient and surface chloride for fly ash concrete which is validated by comparing to other experimental results. A comprehensive approach for estimating the influence of transverse cracking directly above the steel reinforcement on chloride penetration and concrete service life was presented by Bentz et al (2013), concluding that a simple 2D simulation that considers only diffusion can be used to provide a conservative estimate of the influence of cracking on projected concrete service life.…”

Section: Introductionmentioning

confidence: 96%

Experimental and numerical determination of the chloride penetration in cracked mortar specimens

Şoşdean

Marșavina

Schutter

2015

European Journal of Environmental and Civil Engineering

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The presence of cracks in reinforced concrete structures added to the chloride-induced steel corrosion is worldwide one of the major causes of deterioration of reinforced concrete structures, producing loss of structural strength and stability. This study deals with the influence of artificial cracks on chloride penetration in mortar specimens by presenting both the experimental and the numerical results. The experimental results were obtained using chloride penetration tests on mortar specimens of different sizes, with and without artificial cracks, subjected to chloride exposure. Numerical results were obtained using transient finite element analysis by simulating chloride mass diffusion. Comparisons between the results on chloride penetration concluded that the numerical ones obtained using the mass transfer modulus agrees fairly well with the experimental ones. In addition, the influence of certain crack parameters such as crack length, crack depth and also time exposure on chloride ingress was considered.

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“…Several researchers have proposed closed-form solutions for both constant and time-dependent surface chloride models [29][30][31]. In this study, the surface chloride for original concrete is time dependent as shown in the following equation [32]:…”

Section: Time-dependent Surfacementioning

confidence: 99%

“…In this study, the timedependent diffusion coefficient (in mm 2 /year) at the exposure time (t, in years) is represented in terms of a decay function [32] as follows:…”

Section: At Time T Imentioning

confidence: 99%

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

Petcherdchoo

2018

Advances in Materials Science and Engineering

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is paper presents sensitivity of service life extension and CO 2 emission due to silane (alkyltriethoxysilane) treatment on concrete structures under time-dependent chloride attack. e service life is predicted by the Crank-Nicolson-based finite difference approach for avoiding the complexity in solving Fick's second law. e 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 CO 2 emission is assessed. e effectiveness of silane treatment is defined as the ratio of the service life extension to the cumulative CO 2 emission assessed within the corrosion-free service life. e 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. e 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. e cumulative CO 2 emission is most sensitive to either the first application time of silane treatment or the amount of CO 2 emission per application.

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Time dependent models of apparent diffusion coefficient and surface chloride for chloride transport in fly ash concrete

Cited by 149 publications

References 16 publications

Chloride ingress into marine exposed concrete: A comparison of empirical- and physically- based models

Chloride ingress into marine exposed concrete: A comparison of empirical- and physically- based models

Experimental and numerical determination of the chloride penetration in cracked mortar specimens

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

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Time dependent models of apparent diffusion coefficient and surface chloride for chloride transport in fly ash concrete

Cited by 149 publications

References 16 publications

Chloride ingress into marine exposed concrete: A comparison of empirical- and physically- based models

Chloride ingress into marine exposed concrete: A comparison of empirical- and physically- based models

Experimental and numerical determination of the chloride penetration in cracked mortar specimens

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

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