• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.111-117
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• 1995

The alkali-aggregate reaction is a reaction between the alkali metals in the pore water of a concrete and an unstable mineral of the aggregate. There are three types of alkali-aggregate reation which causes deterioration of concrete, such as alkali-silicate reation, alkali-carbonate reaction and alkali-silica reation. Deterioration due to alkali-silica reation is more comon than that due to either the alkali-silicate or alkali-carbonate reaction. The alkali-silica reation is a reaction between the hydroxyl ions in the pore water of a concrete and silica which exists in signigicant quantities in the aggregate. In this PAPER, Alkali-aggregate reactions of mortar made with various abroad aggregate were investigated using XRD, microscope, chemical and physical tests. In additions, the effects of the texture of aggregate, Na, K, CI ion concentrations added to the mortar, on these reactions were studied.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제24권3호
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• pp.1-6
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• 1979

Amylose content and alkali digestibility value of rice grain were tested from 10days after flowering up to maturity. Both amylooe content and alkali digestibility value showed slightly lower at earliest stage, but they reached maximum value by 20 days after flowering, and then they maintained the value until maturity. Both amylose content and alkali digestibility value showed negative correlations to air temperature, though they were not significant statistically except in case of amylose content and maximum temperature, which showed significant correlation in some year.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 1993년도 가을 학술발표회 논문집
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• pp.108-112
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• 1993

The term Alkali-Silica Reaction (ASR) is used to describe a reaction between certain siliceous aggregates and hydroxyl ions present in the pore fluid of a concrete. The ASR is affected by the content of alkali, the particle size and the content of reactive aggregate, water-cement ratio, humidity, temperature and so on. In this paper, the fluence of alkali content and kind of added alkali to the ASR was studied. As a result, the more the content of alkali was increased, the more the mortar-bar was expand and the expansion of mortar-bar was showed differently with the added alkali kinds, The reaction products by ASR were observed by SEM(Scanning Electron Microscope) and analyzed by EDXA(Energy Dispersive X-ray Analysis) also and showed a gel composed of alkali(Na+, K+), silica and calcium.

• Journal of the Korean Ceramic Society
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• 제13권4호
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• pp.15-19
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• 1976

Mutual interferences of alkali and alkali-earth metals in atomic absorption were examined. For determination of Na or K interfering elements increase the absorbancy, and for Ca or Mg decrease. Since influences of coexisting elements become nearly constant by addition of large amount of same coexisting element, could be use mixed standard solution for alkali or alkali-earth metal determination in the presence of other alkali and alkali-earth metals. The metals can be readily incorporated into scheme of rapid silicate analysis. Precision and accuracy are good.

• Journal of the Korean Ceramic Society
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• 제22권2호
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• pp.25-32
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• 1985

Effect of alkali $SO_3$ and $C_2S$ content and cooling condition of clinker on the formation of unstable alkali and cooling condition of clinker on the formation of unstable alkali was investigated. As a result alkali and $SO_3$ content of clinker were the main factors of unstable alkali formation and equation (7) in which the two factors were the variables showed a good agreement with the observed results. Water soluble alkali content of sulphate was decreased with increase of $C_2S$ content of clinker resulted by the increase of solid solution rate of alkali to clinker minerals. But change of unsatble alkali content accordint to the increase of $C_2S$ content was slight. A increasing tendency of ignition loss of clinker with increase of unstable alkali content was found.

• Journal of the Korean Graphic Arts Communication Society
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• 제2권1호
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• pp.23-33
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• 1984

Color providing compounds on image transfer process in color photo graphy was studied with polaroid and Kodak products as a model. These compounds was inititally alkali-mobile or alkali-immobile. Alkali-mobile compunds require imagewise immobilifation in the process or alkali immoble compounds require mobilization by the cleavage reaction. As a result of studies, the polaroid products was showed alkali mobile and Kodak product represented alkali immobile.

• Journal of Korea Foresty Energy
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• 제18권2호
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• pp.70-77
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• 1999

The behaviors of alkali swelling in four major Korean woods were examined as a function of concentration cf alkali solution. Density of alkali-treated woods increased highly with increasing alkali concentration in both softwoods and hardwoods. Wood samples swelled in dimension during alkali swelling, and thereafter they shrank highly by water washing and air drying. The air-dried wood samples after alkali treatment showed almost isotropic shrinkage in tangential and radial direction.

• International Journal of Highway Engineering
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• 제14권6호
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• pp.37-43
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• 2012

PURPOSES : This study is to evaluate the feasibility of setting the standard of cement alkali content by using ASTM C 1260(accelerated mortar bar test) METHODS : This study analyzes the ASR(alkali silica reaction) expansion of cement mortar bar based on the changes in the aggregate type(fine, coarse), cement type(ordinary, low alkali), and replacement contents of fly ash. ASR tests were conducted according to ASTM C 1260. RESULTS : In this test results, There is no big difference in the ASR expansion between ordinary cement and low alkali cement. From this test results, it was found that the variation of cement alkali content did not have a effect on ASR expansion because mortar bar was placed in a container with sufficient alkali aqueous solution at high temperature during the test process of ASTM C 1260. CONCLUSIONS : It is evidently clear that the alkali content of cement have a effect on ASR. But ASTM C 1260 is difficult to assess this effect.

• Journal of the Korean Ceramic Society
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• 제22권3호
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• pp.60-66
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• 1985

The formation mechanism of unstable alkali and its existing states in the clinker were studied. The relation of unstable alkali content vs. other water-soluble components porosity and the distributionof potassium were investigated. The results are as follows :1) Two states of unstable alkali seem to exist in clinker ie compounds of $K_2O-Al_2O_3$ system and free $K_2O$ 2) The content of water-soluble $Al_2O_3$ tends to increase with increase of unstable alkali content, 3) Most of alkalies in clinker are concentrated in liquid phase at high temperature. Therefore it is possible to make various $K_2O-Al_2O_3$ system compounds according to the content of $K_2O$ in the liquid phase of clinker. In this experiment we found out a $K_2O-Al_2O_3$ compound of high $Al_2O_3$ content (34%) and high $K_2O$ content (33%) in clinker with 1.09% unstable alkali. 4) The porosity of clinker tends to increase with increase of unstable alkali content. 5) The amount of trapped alkali vapor may increase in closed pore in the clinker with high alkali and low $SO_3$ condecent. Therefore free $K_2O$ is the condensed alkali on the wall of closed pore in the clinker.

• Fashion & Textile Research Journal
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• 제13권6호
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• pp.972-982
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• 2011

The purpose of this study is to improve the method of color developing with alkali solution as a promotor of color developing for feasible use. Cotton fabric was dyed with persimmon extract ranged with 0~3% alkali component with 5 types of strong to mild alkali solution. Heat treatment for color developing was applied to fabric dyed with persimmon extract and alkali mixing solution. Tests were carried out to analyze the change of surface color, ${\Delta},Ea^*b^*$, and water repellent of the dyed cotton fabric. The alkali mixing sample showed higher ${\Delta},Ea^*b^*$ value than control one without alkali mixing on the base of dyed fabric due to high color developing by alkali in the initial step of dyeing process. As alkali concentration increased, deeper dark color appeared on the fabric. The fabric color was changed to more dark in the application of sodium hydroxide, sodium carbonate, potassium carbonate in the initial step of dyeing process but color was not changed by increased heating time. However, the fabric showed a slight dark color with sodium acetate and more color change than that of the fabric dyed with persimmon extract without alkali. Therefore, sodium acetate seemed to a suitable promotor for color developing in persimmon extract dyeing. Property of water repellent was showed after color developing by heating with low concentration of alkali treatment.