• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.149-150
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• 2018

The RC buildings which are constructed on the seaside are followed by KBC(2016) to achieve the minimization of durability damage. To control the corrosion of the reinforced steel bar by salt attack, W/C should be under 0.4 and specified concrete strength is more than 35MPa in the concrete/building construction standard specification. Ready mixed concretes which have usually include the admixtures in Busan were tested to certify the salt attack durability. In the same specified concrete strength, remarkable salt attack durability was evaluated in comparison to OPC.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.39-42
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• 2002

Cloride attack of concrete is one of the important causes of corrosion of reinforcing steel in concrete with carbonation and frost damage. In this paper, the effect of fly-ash on the cloride attack were investigated by varying water binder ratio and fly-ash contents according to the chloride ion penetrationa test. (ASTM C 1202-94) The principal conclusions from this research were as follows: 1) The compressive strength of concrete at large ages, depends more on $C_2$S contents of base cement than fly-ash contents. 2) On the other hand, the chloride ion penetration of concrete at large ages, principally depends on fly-ash contents and the influence of type of base cement is insignificant.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.291-292
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• 2009

In this study, an analysis of cover concrete cracking exposed to the chloride attack was performed based on newly defined durability limit states. Using the methodology in this paper, the prediction of cover concrete cracking and subsequent spalling can be used for the prediction of corrosion induced serviceability degradation of concrete structures subjected chloride attack.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.229-234
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• 1997

Recently many concrete structures have been deteriorated due to the corrosion of reinforcing steel caused by chloride attack. The chloride attack causes very rapid and serious deterioration. Therefore, It is necessary for highly reliable method to stop the corrosion. Especially, on damaged concrete, it is difficult to stop the progress of steel corrosion that has already occured in concrete. The indirect method of corrosion protection such as eliminating corrosion factors by coating would be hard to be expected for complete stop of corrosion. In this paper, we applied the cathodic protection to chloride attacked marine concrete structures and verified the effect in addition to application of cathodic protection.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.519-522
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• 2005

Ka-Hwa highway bridge, located in a corrosive marine environment, had been examined the current condition of reinforcement corrosion in concrete throughout half-cell potentials, electrical resistivity, chloride contamination of concrete, and visual observation. According to the test, the chloride corrosion reinforced concrete structure is not only the protecting film around the reinforcement is deteriorated but also corrosion activity develops, for example, delamination areas of concrete. The purpose of this paper is to report the effects of Ka-Hwa highway bridge damaged by chlodide attack and to present the results of repair of Ka-Hwa highway concrete bridge in domestic marine environment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.46-52
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• 2017

Recently durability design based on deterministic or probabilistic method has been attempted since service life evaluation in RC(Reinforced Concrete) structure exposed to chloride attack is important. The deterministic durability design contains a reasonable method with time effect on surface chloride content and diffusion coefficient, however the probabilistic design procedure has no consideration of time effect on both. In the paper, a technique on PDF(Probability of Durability Failure) evaluation is proposed considering time effect on diffusion and surface chloride content through equivalent surface chloride content which has same induced chloride content within a given period and cover depth. With varying period to built-up from 10 to 30 years and maximum surface chloride content from $5.0kg/m^3$ to $10.0kg/m^3$, the changing PDF and the related service life are derived. The proposed method can be reasonably applied to actual durability design with preventing conservative design parameters and considering the same analysis conditions of the deterministic method.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.731-736
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• 2002

The degradation of reinforced concrete (RC) structures due to physical and chemical attacks has been a major issue in construction engineering. Deterioration of RC structures due to chloride attack followed by reinforcement corrosion is one of the serious problems. The objective of this study is to develop a form of mathematical model of chloride ingress into concrete. In order to overcome some limits of the previous approaches, a mathematical model of chloride ingress into concrete consisting of chloride solution intrusion through the capillary pore and chloride ion diffusion through the pore water was proposed. Moreover, the variability of diffusivity of chloride ion due to degree of hydration of concrete, relative humidity in pore, exposure condition, and variation of chloride binding was considered in the chloride ingress model.

• Structural Engineering and Mechanics
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• v.85 no.2
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• pp.197-206
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• 2023

The deterioration caused by chloride penetration and carbonation plays a significant role in a concrete structure in a marine environment. The chloride corrosion in some marine concrete structures is invisible but can be dangerous in a sudden collapse. Therefore, as a novelty, this research investigates the ability of a non-destructive damage detection method named the Power Spectral Density (PSD) to diagnose damages caused only by chloride ions in concrete structures. Furthermore, the accuracy of this method in estimating the amount of annual damage caused by chloride in various parts and positions exposed to seawater was investigated. For this purpose, the RC Arosa bridge in Spain, which connects the island to the mainland via seawater, was numerically modeled and analyzed. As the first step, each element's bridge position was calculated, along with the chloride corrosion percentage in the reinforcements. The next step predicted the existence, location, and timing of damage to the entire concrete part of the bridge based on the amount of rebar corrosion each year. The PSD method was used to monitor the annual loss of reinforcement cross-section area, changes in dynamic characteristics such as stiffness and mass, and each year of the bridge structure's life using sensitivity equations and the linear least squares algorithm. This study showed that using different approaches to the PSD method based on rebar chloride corrosion and assuming 10% errors in software analysis can help predict the location and almost exact amount of damage zones over time.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.771-776
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• 2001

Test results on the deterioration process of concrete under single and combined attacks of chloride penetration have been obtained. After test period of 52 weeks, it is found that the internally penetrated chloride ion contents are less in the single attacks of chloride than the combined attacks of chloride and sulfate. Both the diffusion coefficients and surface chloride concentration derived form the chloride profiles showed a time dependence. Also the performance of fly ash-blended cements was observed to be better than plain cements in retarding chloride attack. However it should be needed that improved chloride diffusion model for the combined deterioration process.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.254-260
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• 1997

Chloride-induced corrosion of reinforcement is one of the main factors which cause the deterioration of concrete structures. Durability and service lives of the concrete sturctures should be predicted in order to minimize the risk of corrosion of reinforcement. The objective of this study is to suggest the basis of analytical methods of predicting the corrosion threhold time of concrete structures. Based on the chemistry and physics of chloride ion transport and corrosion process, chloride intrusion with various exposure conditions, variability of diffusivity and transport of pore water in concrete are taken into consideration in applying finite element formulation to the predicion of corrosion threhold time. The effects of main factors on the prediction of chloride intrusion and corrosion threhold time are examined. In addition, after chloride diffusivities of several mixture proportions with different parameters are measured by chloride diffusion test, the exemplary anayses of corrosion threhold time of those mixture proportions are carried out.