• 한국농공학회지
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• 제18권4호
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• pp.4265-4273
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• 1976

1. Fine aggregates of concrete are very important for the construction works and construction cost determination. Most of fine aggregates are from the river sand, but the amount of storage in the river side is steadily decreasing due to continuous construction works. Therefore, another source of fine aggregates is needed to meet increasied demand of sand. 2. Beach sand is a possible source of fine aggregates. But rust of steel bar is caused by CL-chemical of beach sand. Therefore, desalinization of beach sand is requested to get durable reinforced concrete. Economical methods of desalinization are as follows. (a) Flooding and drainage method. (b) Washing of beach sand with water supply and mixing. (c) Spreading of beach sand on the land and leaching by rain water for a few month. 3. Hardening of concrete with beach sand is accelerated due to salt, Thus early stage strength increase leads to make cracks. Also later stage strength decreases and durability becomes worse. By using appropriate admixture, the quality of concrete can be improved.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.316-320
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• 1996

It is now increasingly recognized that the fluid properties of superplasticized high flowing concrete can be affected by numerous parameters which characterize either the cement, the mineral or chemical admixture, the mix proportion. Particularly performance of superplasticizers used to enhance the workability and obviously plays a key role in the rtheology of fresh and engineering properties of hardened concrete. In this experiment, it is aimed to investigate and compare the each fluidities and engineering properties of high flowing concrete by performance in each 3 kinds of superplasticizers. And there is to aim the considering about fluidity and viscocity, hardened properties of hig flowing concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.149-154
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• 1997

In order to predict the onset of the corrosion of steel bars in the concrete, a mathematical model including the diffusion of chloride ion in aqueous phase of pores, the adsorption and desorption of chloride ions to and from the surface of solid phase of concrete, and the chemical reaction of chloride ions with solid phase was established. Finite element method was employed to carry out numerical analysis. The chlorides penetrating through the wall of concrete structure from the external environment and the chlorides contained in the concrete admixture were confirmed to be two important factors to determine the onset of corrosion of steel bars.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.345-348
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• 2005

This paper presents the result of adiabetic temperature rise and fundamental properties of concrete combining admixtures. According to results, difference of setting time with I5.5hours is observed between S-P and R-F30 mixture. Based on the adiabetic temperature rise test, 8$^{circ}C$of heat producted occurs between E-P and R-F30 mixture. is applied to estimate the temperature rising under adiabetic curing condition, which exhibits closer consistency with tested value. The function mentioned above can account for the effect of dormant period in hydration process at early stage on hydration heat production. It reveals that the consideration of placing layer based on the mixture adjustment(E-P mixture at top layer and R-F30 mixture at bottom layer) in mass concreting will contribute to reduce hydration heat as well as alleviate tensile stress discrepancy between placing layer.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.457-460
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• 2008

최근의 콘크리트 기술은 시멘트 제조기술의 발전 보다는 화학 혼화제의 기술발전에 의하여 성장하였다. 현재, 콘크리트 산업에 주로 사용되고 있는 4가지 화학 혼화제로서 변형된 리그닌(LS), 나프탈렌계(SNF), 멜라민계(SMF) 및 폴리카르복실레이트계(PC)계가 있다. 본 연구에서는 SMF계 고유동화제를 멜라민과 포르말린의 몰비를 변화 시키며 4단계로 나누어 반응을 진행시켰다. 합성된 SMF계 고유동화제를 시멘트 콘크리트에 적용하여 작업성, 슬럼프 손실 및 압축강도를 SNF와 비교하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.201-202
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• 2019

The high performace water reducing agent with three-hours-fluidity-retention performance is developed for the purpose of entering into the global market belonging to extreme environment such as Southeast Asia and the Middle East. In this study, the fresh and mechanical properties of the high strength concrete with three-hours-fluidity-retention performance are evaluated by making mock-up members in Vietnam.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.821-824
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• 2006

As this study is to estimate long term resistance of cement mortars using crushed sand under chemical attacks. Besides tests have been carried out with cement mortars by river sand and crushed sand by fine sand, cement mortars mix various proportions of silica fume and fly ash(up to 15% and 50% by weight for cement) were prepared and immersed in pure water, sodium sulfate solution, magnesium sulfate solution, seawater for 28days, 90days, 180days, 365days. Test on the change in the weight and compressive strength of cement mortars according to the duration of immersion time and the content of silica fume and fly ash was performed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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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.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.131-132
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• 2011

This study analyzes the yearly-best delivered size range of truck mixer based on the specified mix, Water to Binder Ratio, aggregate proportion and unit amount with statistical method targeting on Kyeongi and Kyeongsang province and compares with the similar materials of Japan to propose as a basic standard for the quality control of mixer truck. As a result, in case of the Water to Binder Ratio of these areas, it is higher than Japan's due to the excessive safety rate reflecting the changes of differential value impact and unit amount, and the unit amount's standard deviation is very large by reflecting the changes of the amount used and chemical admixture susceptibility. In case of aggregate proportion, the frequency rate is about 50%, which is very similar value with Japan's one.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1976년도 제7회 학술발표회
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• pp.182.3-182
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• 1976

A laboratory study was made for developing an fermentative method of producing conventional Korean soy sauce type of product from sandfish and defatted soy bean Koji of Aspergillus oryzae as raw material and enzme source, respectively. As an attempt to shorten the fermentation period, the admixture, consisting of pre-chopped sandfish slurry and the Koji of Asp. oryzae (100：15, wet fish weight/dry Koji weight) with added water equal to the fish weight (v/w), was first allowed, while being agitated at 450rpm, to undergo digestion for a 5 hour period at $50^{\circ}C$ with no added salt and then then, after adding 20％ salt (w/v), the hydrolysate mixture was ripened for up to 13 weeks at $30^{\circ}C$ and $45^{\circ}C,$ At intervals, an aliquot was withdrawn for determining microbiological, chemical and organoleptic changes taking place in the sandfish-defatted soy bean koji mixture during both digestion and ripening period.