• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.9-15
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• 2001

The low-durability performance of concrete structure occurs by interactive deterioration factors. In particular, carbonation increased with its time elapse is known as the general manner of deterioration characteristics. Recently, the fundamental researches of the carbonation mechanism, besides method and technique for durability improvement of deteriorated structure are advanced actively. So in this paper, alkali-recovery and maintenance performance when the impregnating alkalization agents are used, are compared and examined quantitively with the basis of past proposed study. As a result, alkali-recovery performance be ensured by impregnating alkalization agent on the carbonated concrete which has low pH by accelerated carbonation test. And alkali maintenance performance was effected by the finishing materials on the alkali recovered concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.605-608
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• 2008

We have studied statistically about quality difference of Blast furnace slag Type Ⅲ that affects carbonation of concrete. According to KS F 2563 blast furnace slag was classified 3 types. Type Ⅲ blast furnace slag(specific surface area is $4000cm^2/g$) from different providers with Type A, the B and the C. The statistical technique was applied to exclude error of engineering judgement. T test and F test were used among 3 groups to investigate statistical meaning. The effect which on the quality of blast furnace slag type Ⅲ that affects carbonation of concrete is significant.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.65-70
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• 1993

The effect of particle size of Al powder, water repellent agent and finishing agent on frost resistance, absorption ratio and structure of micropore was examined to improve the physical properties and durability of ALC. According as the amount added of water repellent agent was increased, frost resistance was improved and absorption ratio was decreased. From one side freezing /thaw test, finishing agent which has a low vapor permeation located the crack at close indoor point of ALC specimen. ALC produced from fine Al powder has a low volume reduction by scalling and a sound appearance after freezing/thawing test and top surface freezing test, The crystal of tobermorite in ALC matrix was converted to calcium carbonate by carbonation which was accelerated with the decreasing of water content. Since the micropore of ALC was filled up by calcium carbonate, void ratio was reduced and crack was detected after complete carbonation.

• Corrosion Science and Technology
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• v.15 no.1
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• pp.28-37
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• 2016

Due to the increased construction of offshore concrete structures and the use of de-icing salts for the purpose of snow removal, the needs for the development of anti-corrosive concrete are increasing. To solve these problems, an evaluation of the mechanical and durability properties for concrete were conducted by mixing modified-sulfur as 0 %, 5 %, 10 %, 15 % cement weight ratio. Both strengths and the properties affecting durability such as water absorption coefficient, chloride ion permeability, accelerated carbonation resistance, rapid freezing and thawing, and chemical resistance were evaluated. All evaluations performed were according to the test specifications associated KS. The results indicate that mixing of modified-sulfur lowed chloride ion permeability and improved chemical resistance.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1549-1554
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• 2008

In this paper, The evaluation of durability of the PC Panel lining for tunnel structure was examined through the rapid test by carbonation and freezing and thawing. Also for the purpose of improvement of durability. Namely, the durable characteristics of PC Panel lining by carbonation and freezing and thawing, was evaluated by rapid test and long-term field exposure test and main influence factors were derived. As a result of test, Correlation of accelerating test in deterioration chamber and long-term field exposure test, it will be expected that the proposed correlation well to the prediction of life expectancy of structure and is contributed greatly in the future.

• The korean journal of orthodontics
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• v.48 no.1
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• pp.48-56
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• 2018

Objective: The purpose of this study was to determine the effects of carbonated water on etched or sealed enamel according to the carbonation level and the presence of calcium ions. Methods: Carbonated water with different carbonation levels was manufactured by a soda carbonator. Seventy-five premolar teeth were randomly divided into a control group and 4 experimental groups in accordance with the carbonation level and the presence of calcium ions in the test solutions. After specimen preparation of the Unexposed, Etched, and Sealed enamel subgroups, all the specimens were submerged in each test solution for 15 minutes three times a day during 7 days. Microhardness tests on the Unexposed and Etched enamel subgroups were performed with 10 specimens from each group. Scanning electron microscopy (SEM) tests on the Unexposed, Etched, and Sealed enamel subgroups were performed with 5 specimens from each group. Microhardness changes in different groups were statistically compared using paired t-tests, the Wilcoxon signed rank test, and the Kruskal-Wallis test. Results: The microhardness changes were significantly different between the groups (p = 0.000). The microhardness changes in all experimental groups except Group 3 (low-level carbonated water with calcium ions) were significantly greater than those in the Control group. SEM showed that etched areas of the specimen were affected by carbonated water and the magnitude of destruction varied between groups. Adhesive material was partially removed in groups exposed to carbonated water. Conclusions: Carbonated water has negative effects on etched or sealed enamel, resulting in decreased microhardness and removal of the adhesive material.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.5
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• pp.254-259
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• 2012

The mechanical property enhancement was studied using fly ash produced from fluidized bed type boiler in power plant, which contains a lot of Ca component being used to carbonate for $CO_2$ fixation in the lightweight aggregates made of cement and some portion of fly ash as a cement substitution under the supercritical condition. Specimens having various fly ash substitution rates and curing periods were carbonated under the supercritical condition at $40^{\circ}C$. The weight change rate, carbonation rate by TG/DTA analysis, 1% Phenolphthalein test, specific gravity and mechanical compression strength test were performed to observe the mechanical property enhancement of the cemented materials after carbonation under the supercritical condition and to make sure those could be classified as lightweight aggregates having specific gravity under 2.0.

• Journal of the Korea Institute of Building Construction
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• v.23 no.4
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• pp.349-358
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• 2023

This research aimed to enhance the initial strength of concrete that is mixed with ground granulated blast furnace slag, as well as to fortify its resistance to carbonation and chloride ion permeation. To achieve this, alkaline aqueous, produced through the electrolysis of potassium carbonate, was employed as the mixing water in the preparation of concrete. To substantiate the increment in initial strength, compressive strength measurements of the concrete were executed. Additionally, an accelerated carbonation test and a chloride ion permeation resistance test were undertaken. The results confirmed that the initial strength of the concrete, which utilized electrolysis alkaline aqueous as mixing water, exhibited an improvement in comparison to concrete mixed with conventional water. It was also verified that both carbonation resistance and chloride ion permeation resistance showed enhancements.

• International Journal of Concrete Structures and Materials
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• v.6 no.3
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• pp.155-163
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• 2012

In order to predict the neutralization of concrete which is the reaction of carbonation dioxide from the outside and cement hydration product, such as calcium hydroxide and C-S-H, it was studied the numerical analysis method considering change of the pore structure and relative humidity during the neutralization reaction. Diffusion-reaction neutralization model was developed to predict the neutralization depth of concrete with coating finishing material. In order to build numerical analysis models considering outdoor environment and finishing materials, the adaption of proposed model was shown the results of existing outdoor exposure test results and accelerated carbonation test.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.525-526
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• 2009

On this paper we induce calcite($CaCO_3$) precipitation using microbial biomineralization of the Sporosarcina pasteurii and evaluate required performance evaluation by adjusting it to mortar. As a result carbonation normal mortar test piece(C3S-W) and mortar test piece(C3S-S.p) mixed with Sporosarcina pasteurii, reaction of C3S-S.p was late than C3S-W. Also, in the case of carbonation experiment of C3S-S.p curing in the Urea-CaCl2 aqueous solution(Medium) during 28days and durability of the C3S-W, durability of the mortar test piece(C3S-S.p) mixed with Sporosarcina pasteurii become higher than normal mortar test piece(C3S-W).