• Proceedings of the Korea Concrete Institute Conference
• /
• 2000.10b
• /
• pp.1233-1237
• /
• 2000

In this study, we measured and assay the analysis of chloride ion in cement hydration by the standard method of JCI and understand the mutual relation between added contents and result. The purpose of this research is to provide fundamental information for the deterioration of the reinforcing concrete on account of steel of reinforced steel to repress.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.385.1-385.1
• /
• 2002

Cordyceps has been used as a tonic for replenishing vital function in Chinese traditional medicines. As an attempt to obtain fundamental data for the kidney function, MeOH Ex. and its hexane. ethyl acetate, butanol and water fractions of cultivated Cordyceps pruinosa on mercuric chloride induced renal failure rats were investigated. Urin volume. blood parameters(urea nitrogen. uric acid. creatinine) and urinary electrolytes content (natrium. potassium. chloride) were determined. MeOH extract and butanol fraction showed diuretic effect. (omitted)

• Journal of the Society of Disaster Information
• /
• v.7 no.1
• /
• pp.21-31
• /
• 2011

The objectives of this study is replaced Silicafume with Metakaolin that is used to lightweight concrete to better performance. So, this study made high-performance lightweight concrete using Metakaolin and characteristics of the fundamental properties and chloride ion diffusion. Consequently, it is compressive strength and chloride ion penetration resistance is lower than lightweight concrete using Silicafume, the performance of compressive strength contrast Silicafume is about 88 to 95%. Also, this study got a content result because the chloride ion penetration resistance showed the performance in around 80 to 90%. As a result, this study insist that replacement ratio of Metakaolin is suitable for 10 to 15%.Silicafume and Metakaolin have similar characteristics. In addition, it is similar to the performance of alternative materials is possible.

• Computers and Concrete
• /
• v.23 no.1
• /
• pp.69-80
• /
• 2019

Modeling approach for mesoscopic model of concrete depicting mass transportation and physicochemical reaction is important since there is growing demand for accuracy and computational efficiency of numerical simulation. Mesoscopic numerical simulation considering binder, aggregate and Interfacial Transition Zone (ITZ) generally produces huge number of DOFs, which is inapplicable for full structure. In this paper, a three-dimensional multiscale approach describing three-phase structure of concrete was discussed numerically. An effective approach generating random aggregate in polygon based on checking centroid distance was introduced. Moreover, ITZ elements were built by parallel expanding the surface of aggregates on inner side. By combining mesoscopic model including full-graded aggregate and macroscopic model, cases related to diffusivity and thickness of ITZ, volume fraction and grade of aggregate were studied regarding the consideration of multiscale compensation. Results clearly showed that larger analysis model in multiscale model expanded the diffusion space of chloride ion and decreased chloride content in front of rebar. Finally, this paper addressed some worth-noting conclusions about the chloride distribution and rebar corrosion regarding the configuration of, rebar diameter, concrete cover and exposure period.

• Advances in concrete construction
• /
• v.12 no.6
• /
• pp.451-459
• /
• 2021

The mechanical behaviors and chloride resistance performance of fiber reinforced cementitious composites (FRCC) with hybrid polyethylene (PE) and steel fiber (in total 2% by volume) were investigated. Based on micro-mechanics and fracture mechanics, the reason why the tensile strain capacity of FRCC changed obviously was obtained. Besides, the effects of the total surface area of fiber in FRCC on compressive strength and chloride content were clarified. It is found that the improvement of the tensile strain capacity of FRCC with hybrid fiber is attributed to the growth of strain-hardening performance index (the ratio of complementary energy to crack tip toughness). As the total surface area of fiber related with the interfacial transition zone (ITZ) between fiber and matrix increases, compressive strength decreases obviously. Since the total surface area of fiber is small, the chloride resistance performance of FRCC with hybrid PE and steel fiber is better than that of FRCC containing only PE fiber.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.10a
• /
• pp.227-232
• /
• 1999

In this paper, a laboratory investigation was carried out to estimate the strength improvement of quicklime mixture for the effective use of surplus soils, and the shear strength with curing time was estimated at the content of lime. The effect of strength improvement has been established through the change of lime content with chlorides and sulfates from the samples taken at Samsan region, Ulsan. The test results indicated that the presence of calcium sulphate encouraged the efficiency of lime stabilization, and increased shear strength. Furthermore, it is necessary for inquiring into the relationship between the characteristics of strength and the chemical components.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.55 no.3
• /
• pp.123-128
• /
• 2013

This study was performed to evaluate the slump flow, air content, setting time, compressive strength, adiabatic temperature rise and diffusion coefficient of chloride used ordinary portland cement, crushed coarse aggregate, crushed sand, river sand, fly ash, limestone powder, blast furnace slag powder and superplasticizer to find optimum mix design of low carbon green concrete for structures. The performances of low carbon green concrete used fly ash, limestone powder and blast furnace slag powder were remarkably improved. This fact is expected to have economical effects in the manufacture of low carbon green concrete for structures. Accordingly, the fly ash, limestone powder and blast furnace slag powder can be used for low carbon green concrete material.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.26 no.4
• /
• pp.57-64
• /
• 2022

Chloride, which is one of the main deterioration factors in reinforced concrete structures, can degrade the performance of the structure due to chloride-induced corrosion of steel. Chloride content at steel depth or the rate of chloride penetration is necessary to determine deterioration of reinforced concrete or to calculate initiation time of steel corrosion caused by chloride attack. Chlorides in concrete are generally identified with typical two methods including chloride profiling using potentiometric titration method and discoloration method using AgNO₃ solution. The former is advantageous to estimate chloride penetration rate (diffusion coefficient in general) with measured chloride contents directly, but it is laborious. In the case of latter, while the result is obtained easily with the range of discoloration, the error may occur depending on workmanship when the depth of chloride ingress is measured. This study shows that chloride penetrated depth is evaluated with the results obtained from discoloration method through image analysis, thereby the error is minimized by workmanship. In addition, the effect of micro-crack in concrete is studied on chloride penetration. In conclusion, the depth of chloride penetration was quantified with image analysis and as it was confirmed that chlorides can rapidly penetrate through micro-cracks, caution is especially required for cracks in concrete structure.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.05a
• /
• pp.1035-1040
• /
• 2001

The effects of polymer-binder ratio and slag content on the properties of combined wet/dry-cured polymer-modified mortars using granulated blast-furnace slag (slag) are examined. As a result, the flexural and compressive strengths of polymer-modified mortar using slag reaches a maximum at a slag content of 40%, and is inclined to increase with increasing polymer-binder ratio. The water absorption, carbonation depth and chloride ion penetration depth tend to decrease with increasing polymer-binder ratio and slag content.

• Food Science and Preservation
• /
• v.23 no.4
• /
• pp.553-559
• /
• 2016

The purpose of this study was to determine the content of phenolics and various anthocyanin compounds, and antioxidant and anticancer activities of the extracts from pomergranates, which were produced in two different regions including Goheung, Korea and California, USA. These pomergrantes were divided into juice, pericarp, and seed parts and each part was extracted with 95% methanol. Content of total phenolics [mg chlorogenic acid equivalents/kg DW] was highest in pericarp, followed by juice and seeds from pomergrantes in both regions. The anthocyanins identified in pomegranate fruit were cyanidin-3,5-diglucoside chloride (Cy3,5G), cyanidin-3-O-glucoside chloride (Cy3G), delphini din-3,5-di-O-glucoside chloride (Dp3,5G), delphinidin-3-O-glucoside chloride (Dp3G), pelargonidin-3,5-di-glucoside chloride (Pg3,5G), and pelargonidin-3-glucoside chloride (Pg3G). Among these, cyanidin-3,5-diglucoside chloride (Cy3,5G) was the major anthocyanin in California pomegranate fruit juice and Goheung pomegranate fruit pericarp. DPPH (1,1-diphenyl-2-picryl hydrazyl radical) free radical scavenging activity was dose-dependently increased, and was higher in pericarp part than juice or seed parts from pomergrantes in both regions. By MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, pericarp extracts from pomergrantes in both regions showed the highest anticancer activity, which was higher on Calu-6 for human pulmonary carcinoma than SNU-601 for human gastric carcinoma. Correlation between polyphenols and anticancer activity on Calu-6 was determined to be in the range of $r^2=0.8904$ to 0.9706.