• 한국환경과학회지
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• 제27권2호
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• pp.75-81
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• 2018

At present research on mining backfill materials is being carried out to prevent ground subsidence and breaking by underground cavern of exhausted mines. However, backfill materials can cause secondary environmental issues such as ground pollution. To solve these issues, liner and cover materials are constructed before backfill materials constructed, to inhibit toxic substances form moving to the surroundings. Liner and cover materials, however, should have an accelerating performance after construction and when the accelerating performance is degraded, the work efficiency can be lowered, and the construction cost can be increased, by many rebound content. Therefore, this study develops mining liner and cover materials, and evaluates their accelerating performance and physical properties of liner and cover materials by types and content of accelerating agent. In case of aluminate accelerating agent, it is mixed with more than 5% of liner and cover materials(binder/ratio); thus an accelerating performance satisfying Korean Industrial Standards(KS) occurs, and in case of alkali-free accelerating agent, when it is mixed with more than 7%(binder/ratio), accelerating performance satisfying KS occurs. The more the accelerating agent capacity increases, the more compressive strength decreases. In addition, it is confirmed that compressive strength of aluminate accelerating agent is more degraded than compressive strength of the alkali-free accelerating agent. It is also confirmed that drying shrinkage stability of the alkali-free accelerating agent is better than the drying shrinkage stability of the aluminate accelerating agent.

• 한국응용과학기술학회지
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• 제10권2호
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• pp.29-33
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• 1993

n-Octyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium chloride, and octadecyldimethylbenzylammonium chloride were synthesized to be used as the accelerating weight loss agent. These synthesized compounds were used for the weight loss treatment of PET textile with sodium hydroxide. From the treatments, it was found that the lower carbon number of high alkyl group existed in quaternary ammonium salts, the better effect of weight loss was acquired. The proper concentration of accelerating weight loss agent was $8{\sim}10g/l$, the proper treatment time was $60{\sim}90$ minutes, the proper treating bath ratio was 1 : 50. It is proved that n-octyldimethylbenzylammonium chloride and dodecyldimethylbenzylammonium chloride are good accelerating weight loss agent.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.497-500
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• 2005

This study was performed to evaluate the characteristics which are slump, air content and time of set in fresh concrete and compressive strength of hardened concrete containing slag powder and fly-ash. Replacement rate of FA is fixed on 10$\%$ and replacement rate of slag powder are 0$\%$, 20$\%$ and 30$\%$. Also AE water-reducing agents(standard type, accelerating type) are used. The results were as follows. (1)Slump flow of concrete using AE water-reducing agents is similar. Flowability is incresed when replacement rate of slag powder is increased due to slag powder's ball bearing reaction.(2)Time of set of concrete using accelerating type agent is more faster than that of concrete using standard type agent because of ettringite generation that promote setting.(3)Early strength of three-component concrete using accelerating type agent is higher than that using standard type agent. Therefore cumulative pore is reduced due to ettringite

• 공업화학
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• 제5권1호
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• pp.63-73
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• 1994

n-Tetradecyldimethylbenzylammonium chloride(TDAC)와 n-tetradecyltrimethylammonium methyl sulfate (TTAM)를 합성하고 각각에 물을 가하여 감량촉진제 용액 TDACW와 TTAMW를 각각 제조하였다. 제조된 TDACW와 TTAMW 각각을 NaOH와 병용하여 PET섬유를 감량가공처리한 결과, 감량률은 TDACW가 TTAMW보다 훨씬 높게 나타났으며, 적정 처리농도는 약 $8g/{\ell}$, 처리시간은 60~90분 및 처리액량비는 1:40~1:50이었다. 밀도와 결정화도는 감량률이 증가할수록 상승하였고, 인장강도는 역으로 감량률이 증가될수록 저하되었다. 또한 감량촉진제와 PET섬유와의 반응메카니즘을 고찰하여 감량촉진제가 촉매로서 작용함을 밝혔으며, SEM으로 감량가공된 PET섬유의 표면형태를 관찰하였다.

• 한국건설순환자원학회논문집
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• 제8권1호
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• pp.105-111
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• 2020

이 연구에서는 화학적 열화 및 생물학적 열화에 노출된 콘크리트의 보호를 위해 개발된 글라이코 캘릭스(glycocalix) 코팅재의 응결속도 및 압축강도 발현에 대한 실리케이트계 급결제 혼입의 영향을 검토하였다. 글라이코 캘릭스 코팅재의 적용처에 따라 제안된 단면 뿜어 붙이기용 및 라이닝 공법용 코팅재 배합에서 실리케이트계 급결제의 첨가량을 10mL/L, 25mL/L 및 40mL/L로 변화하였다. 글라이코 캘릭스 코팅재의 경화속도는 박테리아 고정화 재료 양에 의해서도 영향을 받았는데, 40mL/L의 급결제를 첨가한 단면 뿜어 붙이기 및 라이닝 공법용 배합의 종결시간은 각각 80분 및 318분이었다. 급결제를 첨가한 글라이코 캘릭스 코팅재의 강도 발현은 급결제 첨가량이 증가함에 따라 일반 코팅재에 비해 낮은 결과를 보였다.

• 한국농공학회지
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• 제24권2호
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• pp.67-75
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• 1982

A study on the effect of water reducing agent on the various characteristics of concrete has been conducted. The experimental results of the study are summarized as follows. 1. Slump test for the concrete added water reducing setretarding agent in proper quantity have been conducted. According to the test results, the decreasing rate of slump value become bigger than plain concrete with increase of the unit weight of cement and elapse of time 2. In case the proper quantity content of maximum compressive strength in Fig. 5 of water reducing set retarding agent is added, unit weight of water is decreased about 15% or so as compared with plain concrete. with the increase of water reducing set accelerating agent content unit weight of water is decreased much more, And other hand, amount of air entraining shows the increasing tendency with the increase of water reducing agent content. 3. The adding rate of water reducing agent which produce maximum strength shows that WR-CH and WR-SA which is water reducing set-starding agent is 0.2% and WR-CO is 0.5% and that WS-PO which is water reducing set accelerating agent is 0.5 4. compressive strength jof the concrete made of sulfate resistant cement shows less than the strength of normal portland cement at initial strength but the strength of both cement shows almost same at curing age of 28 days. 5. when proper quantity of water reducing set retarding agent is used, boned strength is increased about 15% at curing age of 28days. 6. According to the result of durability test, dynamic young's mudulus of elasticity at plain concrete is decreased about 50% as compared with initial step at 300 cycle of freezing and thawing after curing age of days. on the contarary the concrete used water reducing agent is decreased less than 7%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.323-324
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• 2010

본 연구는 국내에서 사용하고 있는 숏크리트용 급결제의 알칼리-실리카 반응성을 검토하기 위하여 실시하였다. 따라서 국내산 1종 시멘트에 급결제(알루미네이트계, 알칼리프리계, 시멘트광물계)를 혼입하여 알칼리-실리카 반응에 대한 영향을 검토해 보았다. 시험 결과 비반응성 골재를 사용한 경우 급결제의 등가알칼리 함량이 달라져도 알칼리-실리카 반응으로 인한 유해한 팽창은 발생하지 않았다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1989년도 가을 학술발표회 논문집
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• pp.9-13
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• 1989

The purpose of this paper is to propose a method predetermining the 28-days strength of concrete. In this paper, it was predicted by regression analysis of the relation between 7-days and 28-days strength of fresh concrete and the strength of concrete early cured at $70^{\circ}C$ for rour hours after wet screening and addition of accelerating agent. It is concluded that the formula predeterming the 28-days strength of concrete using 25M/M rubbles from Sam-Cheok and sands from Yon-Gok, by the strength of concrete early cured for 4 hours is Y=-11.45 + 3.686X, where the coefficient of determination of regression-expression is r2=0.938, S=17.94(kg/$\textrm{cm}^2$).

• Journal of the Korean Wood Science and Technology
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• 제23권3호
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• pp.33-39
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• 1995

To accelerate the cure of phenolic resin adhesives for plywood, the complexation with melamine resin and the addition of cure-accelerating agents were discussed. The hot-pressing temperature and time of phenol resin could be decreased by complexation with melamine resin. but the wet glue-joints strength of phenol melamine resin was lower than that of ordinary phenol resin in case of plywood using spruce veneer at core layer. Among the tested cure-accelerating agents. the sodium carbonate showed the greatest effect on shortening gelation time of phenolic resin. In addition, in the manufacturing scale test, the hot-pressing time of phenol resin with the addition of 5 parts sodium carbonate could be shortened about 20% compared with ordinary phenol resin which had same glue-joints properties.

• 한국건설순환자원학회논문집
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• 제6권2호
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• pp.94-99
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• 2018

본 연구에서는 현장의 골조공사에 주로 활용되고 있는 설계기준강도 21~27MPa 범위의 콘크리트를 대상으로 $10^{\circ}C$ 온도조건의 범위에서 기존 조강형 혼화제를 사용한 것 대비 경화촉진제를 복합사용하여 추가 첨가할 경우 1종 보통포틀랜드를 사용한 콘크리트의 초기 강도발현에 미치는 영향을 검토하고자 하였으며, 조강형 혼화제에 경화촉진제를 단일 첨가한 기존 자료와 촉진 효과가 우수한 3가지의 경화촉진제를 선정하여 이에 대한 복합사용에 대한 검토를 수행하였다. 본 연구의 실험결과 $CaBr_2+NaSCN+DEA$를 복합사용한 경우 $CaBr_2$, NaSCN의 단일사용에 비하여 시멘트량 및 혼화제의 사용에 따라 강도발현율이 증가되는 경향이 나타났으며, 단위 시멘트량 $330kg/m^3$ 이상의 조건에서 복합형태의 경화촉진제를 첨가하게 되면 기존 조강형 혼화제 또는 경화촉진제를 단일 사용한 것에 비하여 5MPa 발현시점이 12시간 정도 단축할 수 있는 것으로 확인되었다.