유화처리 바이오디젤이 도포된 콘크리트의 침투깊이 판정

백철 ( Baek Cheol ),김태우 ( Kim Tae-woo ),이재진 ( Lee Jae-jin ),이동윤 ( Lee Dong-yun ),한민철 ( Han Min-cheol ),한천구 ( Han Cheon-goo ) 한국건축시공학회 2017 한국건축시공학회 학술발표대회 논문집 Vol.17 No.2

This study is to provide a evaluation method for the penetration depth of emulsified refined bio diesel(ERBD)applied to a surface of the concrete by using water absorption capability of the concrete. The concrete applied with ERBD was immersed at water for 1 min., 5min., and 10 min. and then was checked the brightness with elapse of time. Test results indicated that there was clear difference between ERBD part and non ERBD part in concrete specimen after measuring the brightness until 120min.

폐유지류가 혼화재 다량 치환 콘크리트의 내구성에 미치는 영향

한민철,우대훈,Han, Min-Cheol,Woo, Dae-Hoon 한국건설순환자원학회 2013 한국건설순환자원학회 논문집 Vol.1 No.3

본 연구에서는 폐유지류가 혼화재 다량 치환콘크리트의 내구성에 미치는 영향을 실험적으로 고찰하고자 한다. 플라이애시 30% 및 고로슬래그 60% 치환한 콘크리트를 대상으로 기초적 물성과, 탄산화저항성, 동결융해저항성, 염해 저항성 및 황산염 침투저항성을 고찰하고 세공구조를 측정하였다. 본 연구에 사용된 폐유지류는 유동성 저하를 방지하기 위하여 유화처리된 폐유지류(ERCO)를 사용하였고, 혼입률은 1.0%까지로 결정하였다. 연구결과에 따르면, 슬럼프 및 공기량은 ERCO 혼입에 따라 감소하는 경향을 보였고, 압축강도는 ERCO혼입에 따라 28일강도는 다소 저하하나 180일 강도의 경우 ERCO혼입과 동등이상의 값을 보였다. 또한, ERCO 혼입에 따른 내염해, 탄산화, 황산염 및 동결융해 저항성에 대하여 분석한 결과로는 염화물 침투저항성 및 탄산화 침투 저항성은 ERCO 혼입률 증가에 따라 저항성이 향상되나, 동결융해 저항성은 저하되는 것으로 나타났다. This paper is to investigate an effect of waste cooking oil(WCO) on the engineering properties and durability of high volume admixture concrete. Fly ash with 30% and blast furnace slag with 60% were incorporated in OPC to fabricate high volume admixture concrete with 0.5 of W/B. Emulsified refining cooking oil(ERCO) was made by mixing WCO and emulsifying agent to improve fluidity. ERCO was replaced by cement from 0.25 to 1.0%. As results, the increase of ERCO resulted in decrease of slump and air contents. For compressive strength, the use of ERCO led to decrease the compressive strength at 28 days, while it had similar strength or much higher strength than plain concrete at 180 days. Resistance to carbonation and chloride penetration was improved with the increase of ERCO contents due to decreased pore distribution by saponification between ERCO and concrete, while freeze-thaw resistance was degraded due to air loss.

등가재령방법에 의한 혼화재 종류별 콘크리트의 압축강도 증진해석

한민철,한천구,Han, Min-Cheol,Han, Cheon-Goo 한국건축시공학회 2007 한국건축시공학회지 Vol.7 No.1

This paper is to investigate the effect of the curing temperature on strength development of concrete incorporating cement kiln dust(CKD) and blast furnace slag (BS) quantitatively. Estimation of the compressive strength of the concrete was conducted using the equivalent age equation and the rate constant model proposed by Carino. Correction of Carino model was studied to secure the accuracy of strength development estimation by introducing correction factors regarding rate constant and age. An increasing curing temperature results in an increase in strength at early age, but with the elapse of age, strength development at high curing temperature decreases compared with that at low curing temperature. Especially, the use of BS has a remarkable strength development at early age and even at later age, high strength is maintained due to accelerated pozzolanic activity resulting from high temperature. Whereas, at low curing temperature, the use of BS leads to a decrease in compressive strength. Accordingly, much attention should be paid to prevent strength loss at low temperature. Based on the strength development estimation using equivalent age equation, good agreements between measured strength and calculated strength are obtained.

혼화재 종류 변화에 따른 저온조건하 콘크리트의 초기강도 발현 특성

한민철,Han, Min-Cheol 한국건축시공학회 2007 한국건축시공학회지 Vol.7 No.4

In this paper, tests are carried out in order to investigate the strength development of concrete under various binder types, W/B and curing temperature ranged from $5{\sim}20^{\circ}C$. Fly ash and blast furnace slag were incorporated by as much as 30%, respectively. Strength development of concrete are estimated using Logistic model and strength ratio of concrete at 28days to that at early age are also investigated. According to experimental results, it is found that good agreements are obtained between measured values and calculated ones using logistic model below $20^{\circ}C$. Strength ratio of concrete at 28days to that at early age increases in case W/B decreases and curing temperature increases. Tables and graphs for strength ratio of concrete are provided in this paper. It is capable of obtaining and predicting the periods to attain design strength by considering increment factor of strength easily with the table and graphs presented in this paper. This paper presents the reference data to decide removal time of form, time to reach target strength and strength inspection of remicon whether the test specimens meet the specified criteria of compressive strength. Multi regression models with respect to the relationship between 7days compressive strength and 28 days compressive strength depending on W/B and admixture types are presented.

폐석분 및 바텀애시를 사용한 인공경량골재의 융제(Flux) 종류에 따른 밀도 및 흡수율 특성

한민철,신재경,Han, Min-Cheol,Shin, Jae-Kyung 한국건설순환자원학회 2012 한국건설순환자원학회지 Vol.7 No.3

본 연구에서는 인공경량골재의 주요 물성인 밀도 및 흡수율의 성능 향상을 위하여 융제 종류 및 첨가율에 따른 밀도 및 흡수율 특성을 검토하였다. 실험결과, 화학제품의 융제 사용에 관한 특성으로, $Na_2CO_3$ 및 $CaSO_4$는 경우 낮은 소성온도에서 소성이 가능하나, 흡수율이 증가하였고, $CaCO_3$, NaOH, $Fe_2O_3$는 첨가율이 증가할수록 흡수율은 낮아졌으나, 절건밀도가 높아지는 것으로 나타나 융제로서 부적합하였다. $Na_2SO_4$의 사용한 경우에는 절건밀도 $1.35{\sim}1.50g/cm^3$와 상대적으로 낮은 흡수율로 융제로서 가장 적합하였다. 산업부산물의 융제 사용에 관한 특성으로 유리연마 슬러지는 절건밀도 $1.45{\sim}1.55g/cm^3$ 및 흡수율 9~12 %로 흡수율이 높게 나타났다. 고로슬래그 미분말은 첨가율이 증가할수록 밀도는 높아지고 흡수율은 낮아지는 것으로 나타났다. 산화슬래그는 첨가율 10 %에서 절건밀도 $1.46g/cm^3$, 흡수율 8,5 %로 낮은 절건밀도와 흡수율을 갖는 양질의 인공경량골재를 제조할 수 있었다. In this paper, the physical properties of lightweight aggregate such as density and water absorption according to addition ratio and type of flux were investigated. When using $Na_2CO_3$ as flux of lightweight aggregate, burnability was available at low burning temperature and water absorption increased. And as increasing addition ratio of $CaCO_3$, NaOH, $Fe_2O_3$, absorption decreased and $CaCO_3$, NaOH, $Fe_2O_3$ were considered improper to use flux of lightweight aggregate because of high dried density. $Na_2SO_4$ was proper to use flux of lightweight aggregate due to dried density $1.35{\sim}1.50g/cm^3$ and lower absorption. When using glass abrasive sludge as flux of lightweight aggregate, dried density and water absorption were in the range of $1.45{\sim}1.55g/cm^3$ and 9~12% respectively. It was indicated that as increasing addition ratio of blast furnace slag powder, density increased whereas absorption decreased. In use of oxidizing slag as flux, artificial lightweight aggregate which have dried density $1.46g/cm^3$, water absorption 8,5 % can be manufactured at 10 % of addition ratio.

순환골재 미분말의 최대입경 및 치환방법이 시멘트 모르터의 공학적 특성에 미치는 영향

한민철,전규남,Han, Min-Cheol,Jeon, Kyu-Nam 한국건설순환자원학회 2010 한국건설순환자원학회지 Vol.5 No.4

본 연구에서는 순환골재 미분말 생산 시 발생하는 비산분진 및 미분말 중 입경 0.08 mm이하 및 입경 0.15 mm 이하 순환골재 미분말만을 포집하여 순환골재 미분말의 치환방법 및 치환률에 따른 제반 공학적 특성을 분석하였다. 그 결과 유동성은 0.08 mm 이하 및 0.15 mm 이하의 RP를 치환한 경우 전반적으로 저하하는 경향을 나타내었으나, 0.15 mm 이하의 RP를 사용할 시 0.08 mm 이하의 RP를 사용한 경우보다 상대적으로 고성능감수제가 많이 첨가됨에 따라 플로우 감소 폭은 적은 것으로 나타났다. 0.15 mm 이하의 RP를 사용한 플로우, 링플로우 및 미니슬럼프 플로우의 연관관계는 타 시험방법에 비해 플로우와 링플로우의 경우 연관관계가 큰 것으로 나타났으며, 0.15 mm 이하의 RP를 사용한 페이스트의 소성점도의 경우 RP치환률이 증가함에 따라 점도 및 항복치가 증가하는 것으로 나타났다. 압축강도 및 휨강도의 경우는 입자크기에 관계없이 RP의 치환률이 증가함에 따라 플레인에 비해 강도값이 저하하는 것으로 나타났으며, 재령이 경과함에 따라 강도 발현율이 큰 것으로 나타났다. 또한, 시멘트에 치환한 경우보다 잔골재에 치환할 시 높은 강도값을 나타내었으며, 0.08 mm 이하의 RP를 5% 잔골재에 치환할 시 플레인과 강도값이 유사함을 나타내어 0.08 mm 이하의 RP 사용시 강도 증진 효과가 큰 것을 알 수 있었다. This study is to investigate experimentally the engineering characteristics of cement mortar according to the replacement method and contents of recycled aggregate powder (RP) by collecting the recycled aggregate powder with the maximum size of below 0.08 mm and 0.15 mm. then, the results of the study can be summarized as follows. The flow of flesh mortar represented a trend in decreasing while the recycled aggregate powder was substituted as it is compared with that of plain. In addition, in case of correlation between tests, it appeared that the correlation between flow and ring flow is big. In the case of the characteristics of hardened mortar, the strength showed more improvements as the RP was substituted to aggregate than the case, which is substituted to aggregate. In addition, it was verified that the results in which the RP was substituted to aggregate by 5% represented similar values to that of the plain according to the passage of age.

복합보온양생 방법이 극저온 조건하 플라이애시 치환 콘크리트의 온도이력에 미치는 영향

한민철,손호정,Han, Min-Cheol,Son, Ho-Jung 한국건설순환자원학회 2012 한국건설순환자원학회지 Vol.7 No.3

In this study, temperature profile of the fly ash concrete were studied in accordance with the change of heating curing method combination for the slab concrete in order to develop efficient protection method of the concrete subjected to $-20^{\circ}C$. The slab concretes with the size of $1200mm{\times}600mm{\times}200mm$ were fabricated with W/B of 50% and exposed to $-20^{\circ}C$ for 7 days. Five different combinations of heat curing methods were applied to the slab concrete specimen; two combinations of heat supplying by electrical heater and surface heat insulation material such as polyethylene film and quadrupled layer bubble sheet based on heat enclosure installment; three combinations of heating coil embedment and surface heat insulation materials such as polyethylene film, sawdust and quadrupled layer bubble sheet based on heat enclosure installment. Test results showed that by applying both heating coil and bubble sheet and heat enclosure, the concrete exposed to $-20^{\circ}C$ can be effectively protected from early-age frost damage.

순환 석회암골재를 사용한 초고강도 콘크리트의 특성

한민철,현승용,문병룡,Han, Min-Cheol,Hyun, Seung-Yong,Moon, Byeong-Yong 한국건설순환자원학회 2018 한국건설순환자원학회지 Vol.13 No.1

혼화재 종류가 콘크리트의 공학적 특성 및 건조수축에 미치는 영향

한민철,Han, Min-Cheol 한국건축시공학회 2009 한국건축시공학회지 Vol.9 No.5

In this paper, the engineering properties and estimation of drying shrinkage of concrete incorporating fly ash (FA), blast furnace slag (BS) and cement kiln dust (CKD) were discussed. FA, BS and CKD contents ranged from 0% to 20%. Water to binder ratio (W/B) also ranged from 40 to 50 %, with a 5% interval. For estimating drying shrinkage, an exponential model proposed by the author was applied, According to results, the use of FA, BS and CKD resulted in a decrease of flowability and air contents. As expected, the use of admixtures also decreases the early age strength of concrete, while at later age, due to a pozzolanic reaction of FA and BS, the compressive strength was recovered to a value comparable with that of plain concrete. For drying shrinkage, the use of admixtures led to an increase in the drying shrinkage of concrete. The exponential model suggested by the author showed good agreement between the calculated and experimental values both at early age and at later age. 본 연구에서는 실무에서 주로 사용되고 있는 FA, 35 및 CKD 치환률에 따른 콘크리트의 기초적 물성 및 건조수축에 미치는 영향을 분석하고 이를 토대로 건조수축 해석을 실시하여 혼화재가 콘크리트의 건조수축에 미치는 영향을 정량적으로 평가하고자 한다. 실험변수로서 혼화재 치환률은 $0{\sim}20%$ 수준으로 결정하였고, W/B는 $40{\sim}50%$의 수준으로 결정하였다. 건조수축해석을 위해 지수함수모델을 적용하였다. 연구결과에 따르면, 혼화재 치환율이 증가함에 따라 유동성 및 공기량이 감소하였으며 초기압축 강도가 저하됨을 확인 하였다. 건조수축 특성으로 혼화재 치환률이 증가함에 따라 건조수축은 증가하는 경향을 보였으며, 건조수축 해석결과 지수함수 모델이 측정치를 양호하게 추정함을 알 수 있었고, 혼화재의 영향을 고려할 필요성이 제기되었다.

식물성 유지 및 폐식용유를 사용한 고강도 콘크리트의 자기수축 및 공학적 특성

한민철,이동규,Han, Min-Cheol,Lee, Dong-Gyu 한국건설순환자원학회 2011 한국건설순환자원학회지 Vol.6 No.3

본 연구에서는 콩기름과 자원 재활용 차원의 폐식용유의 새로운 자기수축 저감방안으로서의 가능성을 검토하고자 수축저감제 및 팽창재와 비교 분석하였는데, 그 결과는 다음과 같다. SO 및 WO는 Plain에 비해 유동성이 소폭 저하되었으나 공기량에서는 큰 차이를 보이지 않았고, 강도결과는 재령 28일에 유지류에서 약간의 저하가 발생하였지만 대부분의 수준에서 양호한 결과를 나타냈다. 자기수축 저감효과는 SO와 WO가 RS 및 EA보다 우수함을 확인할 수 있었는데, 이는 SO과 WO의 지방산이 시멘트 수화물 중 $Ca(OH)_2$와 가수분해 반응을 진행하여 지방산 칼슘염을 생성하게 되는데, 이러한 생성물들이 콘크리트 경화체내의 모세관 공극을 충전시켜 수축완화 작용에 기인한 것으로 사료된다. 공극분포 측정결과 SO 및 WO의 경우 치환율에 상관없이 $0.01{\sim}0.1{\mu}m$ 사이즈의 공극이 0 ml/g으로 나타났으며, $10{\sim}100{\mu}m$ 사이즈의 공극이 매우 적은 것으로 나타나 유지류가 콘크리트의 미세공극을 충전해주는 역할을 하는 것으로 판단된다. This study investigated possibilities for a new reducing shrinkage method of soybean oil(SO) and waste oil(WO) to compare with shrinkage reducing agent(RS) and expansion additive(EA). There was no big difference to flow, air contents, and compressive strength of plain to use SO and WO. For the reducing shrinkage performance, SO and WO was more effective than RS and EA, because their fatty acid reacted with calcium hydroxide of concrete to turn soap. For the pore distribution by porosimter, $0.01{\sim}0.1{\mu}m$ pores of SO and WO were 0 ml/g, and $10{\sim}100{\mu}m$ also remarkably lower than any others. In these results, it inferred that they filled up capillary pore and mitigated autogenous shrinkage by their saponification of their fatty acid and calcium hydroxide.