• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.553-556
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• 2006

Chloride penetration is the main reason which causes the deterioration of concrete structures. Chloride penetration of concrete structures due to chemical-physical phenomena can be profitably analyzed by means of model-based simulations. The main purpose of this paper is to analyze chloride penetration considering self-desiccation, convection and admixture(GBFS: granulated blast-furnace slag) effects. Basic governing equations are modified properly to apply these effects to chloride penetration analysis. Temperature and relative humidity data of In-Cheon from Korea Meteorological Administration are used for analyzing chloride penetration.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.166-167
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• 2019

In this study, to test the performance of concrete used as a concrete admixture as a recycling method of CGS, gypsum was mixed and the chloride ion penetration resistance test of CGS and BFS substituted concrete was conducted. As a result, it was found that without gypsum type test specimen, the CGS sustituted test specimens had lower chloride ion penetration resistance than the BFS substituted specimens. When gypsum was added, it was confirmed that the chloride ion penetration resistance was poor regardless of the type of admixture. In addition, it was confirmed that both admixtures were less resistant to chloride ion penetration than OPC, regardless of the presence of gypsum. However, considering the uneven quality variation of coal, which greatly affects the quality of CGS, further research is needed.

• Computers and Concrete
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• v.13 no.1
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• pp.17-30
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• 2014

This research presents the effect of various ground pozzolanic materials in blended cement concrete on the strength and chloride penetration resistance. An experimental investigation dealing with concrete incorporating ground fly ash (GFA), ground bottom ash (GBA) and ground rice husk ash (GRHA). The concretes were mixed by replacing each pozzolan to Ordinary Portland cement at levels of 0%, 10%, 20% and 40% by weight of binder. Three different water to cement ratios (0.35, 0.48 and 0.62) were used and type F superplasticizer was added to keep the required slump. Compressive strength and chloride permeability were determined at the ages of 28, 60, and 90 days. Furthermore, using this experimental database, linear and nonlinear multiple regression techniques were developed to construct a mathematical model of chloride permeability in concretes. Experimental results indicated that the incorporation of GFA, GBA and GRHA as a partial cement replacement significantly improved compressive strength and chloride penetration resistance. The chloride penetration of blended concrete continuously decreases with an increase in pozzolan content up to 40% of cement replacement and yields the highest reduction in the chloride permeability. Compressive strength of concretes incorporating with these pozzolans was obviously higher than those of the control concretes at all ages. In addition, the nonlinear technique gives a higher degree of accuracy than the linear regression based on statistical parameters and provides fairly reasonable absolute fraction of variance ($R^2$) of 0.974 and 0.960 for the charge passed and chloride penetration depth, respectively.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.2
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• pp.71-79
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• 2003

The estimation functions were proposed for calculating diffusion coefficient, chloride binding, and evaporable water. The program estimating chloride ion penetration was developed on the basis of these functions and the effects of humidity, curing temperature, water-cement ratio, and $C_3$A on chloride penetration were analyzed. The relative humidity increases the depth of chloride ion penetration and the trend becomes greater with aging. On the contrary, the influence of curing temperature on chloride ion penetration decreases with aging. By the way, the rise of $C_3$A in cement increases total chloride concentration on the surface as the bound chloride concentration increases but it decreases total chloride concentration on the inner part as the diffusion velocity of free chloride decreases. The fall of water-cement ratio decreases the chloride penetration depth rapidly. Therefore, the reduction of water-cement ratio may be the most effective method for reducing of the steel corrosion by chloride penetration.

• Ocean and Polar Research
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• v.26 no.1
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• pp.43-50
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• 2004

The diffusion model, which considers diffusion and sorption, is proposed. The FEM program developed on the basis of the diffusion model provides the estimation of chloride concentration according to cyclic humidity and sorption. After the humidity diffusion analysis is carried out, the chloride ion diffusion and sorption analysis are conducted on the basis of the preestimated humidity data in each element. Each element has different analysis variables at different ages and locations. At early ages, the difference between inner and outer relative humidity causes the chloride ion penetration by sorption. As the humidity diffusion reduces the difference with age, the effect of sorption on the chloride ion penetration decreases. By the way, the cyclic humidity increases the effect of sorption on the chloride ion penetration at early ages, and the quantity of chloride ion around steel at later ages. Therefore, the in situ analysis of chloride ion penetration for marine concrete structures must be performed considering the cyclic humidity condition and the long term sorption.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.151-152
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• 2017

This tests examined the effectiveness of bacteria slime on the chloride ion penetration resistance of cement mortar. Test results exhibited that the chloride ion penetration depth of mortars including 5% expanded vermiculite immobilizing bacteria was 17% smaller than that of the control mortar without expanded vermiculite.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.172-173
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• 2014

The study is used to verify the applicability of the sensor to monitor penetration of chloride into the concrete, like real coastal environment. After manufacturing the specimen adapt corrosion sensor for chloride penetration monitoring, chloride spray experiment was conducted. And then, It was checked the possibility of monitoring of the penetrated chloride by measuring the resistance of the corrosion sensor that was embedded in each depth of the concrete. Experimental results, it is confirmed that the corrosion resistance of the sensor was increased depending on the concentration of chloride. Therefore, it is estimated that the sensor is available for monitoring of chloride penetration.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.467-472
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• 2000

It is known that chloride ion in concrete destroys the passive film of reinforcement inside concrete and accelerates corrosion which is the most influencing factor to durability of concrete structures. In this thesis, a chloride ion diffusion model for blast furnace slag(BFS) concrete, which has better resistance to both damage due to salt and chloride ion penetration than ordinary portland cement concrete, is proposed by modifying existing model of normal concrete. Proposed model is verified by comparing diffusion analysis results with both results by indoor chloride penetration test for specimens and field test results for actual RC bridge pier. Also, the optimum resistance condition to chloride penetration is obtained according to degrees of fineness and replacement ratios of BFS concrete. As a result, resistance to chloride ion penetration for BFS concrete is more affected by replacement ratio than degree of fineness.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.276-277
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• 2017

Deicing agent affect concrete durability such as scaling, rebar corrosion strength of concrete. In this study, developed deicing agent satisfied with EL610 is evaluated to compare affects to concrete with no deicing agent and chloride-containing deicing agents. Deicing agents are applied to concrete surface during four months twice a week. Chloride content, chloride penetration depth and concrete strength are evaluated. After experiment, chloride content, chloride penetration depth of concrete are as follows. Chloride-containing deicing > Eco friendly deicer > No deicing agents. Concrete strength are also as follows. Chloride-containing deicing > Eco friendly deicer > No deicing agents. From experiment, developed deicing agent shows low chloride content in concrete and affect concrete strength little lower than chloride-containing deicing.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.594-597
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• 2006

Chloride ion penetration and carbonation are the most important factors in the durability problems of reinforced concrete structures. Most of the existing studies on those subjects are focused on the no-crack concrete, though the existence of crack may strongly affect the chloride ion penetration and carbonation. To evaluate the influence of crack on the chloride ion penetration and carbonation and to assess the service life of reinforced concrete more accurately, finite volume analyses (FVA) were performed based on the FV mesh containing the ideal crack whose width is uniform along the depth. Analytical results show that the influence of crack width and depth is much more pronounced for the chloride ion penetration than for the carbonation.