Time dependency of chloride diffusion coefficients in concrete

Visser, J.

doi:10.1617/2912143578.028

Cited by 5 publications

(14 citation statements)

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“…However, Visser et al [56] showed that D app does change with exposure time and therefore, this time dependency should be included in the prediction models. According to the same authors, the following updated formula should be in agreement with this requirement for the continuous exposure condition (Equation (2)):

C (x, t) = {normalC}_{0} + ({normalC}_{normals} - {normalC}_{0}) \cdot [1 - \erf (\frac{normalx}{\sqrt{4 \cdot \frac{{normalD}_{0}}{(1 - n)} {(\frac{{normalt}_{0}}{normalt})}^{normaln} \cdot t}})] normalC

with D 0 , the instantaneous diffusion coefficient (m 2 /s)) at reference time t 0 which is usually 28 days (=0.0767 years) and n, the ageing exponent (−).…”

Section: Methodsmentioning

confidence: 99%

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Quantification of the Service Life Extension and Environmental Benefit of Chloride Exposed Self-Healing Concrete

et al. 2016

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Formation of cracks impairs the durability of concrete elements. Corrosion inducing substances, such as chlorides, can enter the matrix through these cracks and cause steel reinforcement corrosion and concrete degradation. Self-repair of concrete cracks is an innovative technique which has been studied extensively during the past decade and which may help to increase the sustainability of concrete. However, the experiments conducted until now did not allow for an assessment of the service life extension possible with self-healing concrete in comparison with traditional (cracked) concrete. In this research, a service life prediction of self-healing concrete was done based on input from chloride diffusion tests. Self-healing of cracks with encapsulated polyurethane precursor formed a partial barrier against immediate ingress of chlorides through the cracks. Application of self-healing concrete was able to reduce the chloride concentration in a cracked zone by 75% or more. As a result, service life of steel reinforced self-healing concrete slabs in marine environments could amount to 60–94 years as opposed to only seven years for ordinary (cracked) concrete. Subsequent life cycle assessment calculations indicated important environmental benefits (56%–75%) for the ten CML-IA (Center of Environmental Science of Leiden University–Impact Assessment) baseline impact indicators which are mainly induced by the achievable service life extension.

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C (x, t) = {normalC}_{0} + ({normalC}_{normals} - {normalC}_{0}) \cdot [1 - \erf (\frac{normalx}{\sqrt{4 \cdot \frac{{normalD}_{0}}{(1 - n)} {(\frac{{normalt}_{0}}{normalt})}^{normaln} \cdot t}})] normalC

with D 0 , the instantaneous diffusion coefficient (m 2 /s)) at reference time t 0 which is usually 28 days (=0.0767 years) and n, the ageing exponent (−).…”

Section: Methodsmentioning

confidence: 99%

“…The probabilistic limit state function (Equation (3)) used for estimating the time to chloride-induced steel depassivation looks almost identical to Equation (2) of Visser et al [56].

C_{crit} = C_{0} + false(C_{s} - C_{0} false) \cdot [1 - \erf (\frac{d}{\sqrt{4 \cdot k_{e} \cdot \frac{D_{0}}{1 - normaln} \cdot {(\frac{t_{0}}{t})}^{n} \cdot normalt}})]

…”

Section: Service Life Predictionmentioning

confidence: 99%

Quantification of the Service Life Extension and Environmental Benefit of Chloride Exposed Self-Healing Concrete

et al. 2016

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“…The estimation of D 0 was performed using equation (13), which was proposed by Visser (Visser et al, 2002). D 0 is the apparent chloride diffusion coefficient (m 2 /s) of the concrete at the time the structure was commissioned t 0 (6 months), D t is the apparent chloride diffusion coefficient (m 2 /s) at the exposure time t (18.5 months), and n is a concrete age factor (0.23; DuraCrete, 2000).The value obtained for D 0 is 7.32 × 10 -12 m 2 /s.…”

Section: Durability Assessment and Remaining Service Life Estimationmentioning

confidence: 99%

Service-Life Assessment of Existing Precast Concrete Structure Exposed to Severe Marine Conditions

Segura

Cavalaro

Fuente

et al. 2016

J. Perform. Constr. Facil.

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The overall performance of a concrete structure is considered to be a key issue when determining its service life. The widespread use of precast concrete and consideration of durability as a design parameter in most of the international codes have the goal of achieving concrete structures with better durability. Nevertheless, the early deterioration of concrete is still common in a large number of concrete structures, which reduces the service life. This paper presents a case study of an existing precast concrete cooling tower for a thermal power station subjected to severe marine exposure conditions, which showed symptoms of serious deterioration after operating for three years. The main goal of this study was to clarify the origin of the accelerated deterioration of the structure. Wetting-drying cycles were identified as the main cause of the early deterioration of the structure. Furthermore, estimations on its remaining service life were made considering the accelerating effect of the wetting-drying cycles. Finally, the variation in the safety factor of the main structural elements was evaluated.

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“…This paper deals with those problems for a 15% fly ash (FA) concrete designed for marine exposure conditions. Chloride profiling at various exposure times enabled a proper estimation of the chloride surface concentration, the instantaneous reference chloride diffusion coefficient and the ageing exponent in accordance with Visser et al [2002]. Furthermore, monitoring of the corrosion potential provided more information on the minimum value for the critical chloride concentration.…”

Section: Introductionmentioning

confidence: 99%

“…1 by applying non-linear regression analysis on the experimental chloride profiles, usually with omission of the first layer (0-2 mm). However, Visser et al [2002] demonstrated that Dapp changes with exposure time and concluded that this time dependency should be included in the prediction models. According to the same authors, the following model should comply with this requirement for continuous exposure (Eq.…”

mentioning

confidence: 99%

Sustainability Effects of Including Concrete Cracking and Healing in Service Life Prediction for Marine Environments

Heede¹,

Belleghem²,

Keersmaecker³

et al. 2016

Sustainable Construction Materials and Technologies (SCMT)

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With today's focus on sustainable design, it is necessary to adequately predict and prolong service life of concrete in marine environments. By introducing self-healing properties, service life extension can be achieved. However, in prediction models, the required concrete mix specific input is usually not available. Moreover, little attention goes to the unavoidable presence of cracks. Finally, autonomous crack healing has almost never been taken into account. In this paper, the relevant model input was estimated from experimental chloride profiles. It enabled an adequate prediction of the chloride-induced steel depassivation period for cracked and uncracked 15% fly ash concrete (8-104 years, respectively). Comparison with self-healing by means of encapsulated polyurethane indicated a 48-76% self-healing efficiency. It could extend the corrosion initiation period to 36-68 years. Being much less subject to timedependent repair, PU based self-healing concrete has a 77-88% lower environmental impact than traditional (cracked) concrete.

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Time dependency of chloride diffusion coefficients in concrete

Cited by 5 publications

References 0 publications

Quantification of the Service Life Extension and Environmental Benefit of Chloride Exposed Self-Healing Concrete

Quantification of the Service Life Extension and Environmental Benefit of Chloride Exposed Self-Healing Concrete

Service-Life Assessment of Existing Precast Concrete Structure Exposed to Severe Marine Conditions

Sustainability Effects of Including Concrete Cracking and Healing in Service Life Prediction for Marine Environments

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