사면체 메시 모델을 MCNP 지오메트리로 활용하기 위한 TET2MCNP 프로그램 개발

한민철,염연수,Thang Tat Nguyen,최찬수,이현수,김찬형 대한방사선방어학회 2016 대한방사선방어학회 학술발표회 논문요약집 Vol.2016 No.12

등가재령 방법에 의한 플라이애시를 치환한 시멘트 모르타르의 강도 증진 해석

한민철,Han, Min-Cheol 한국건설순환자원학회 2012 한국건설순환자원학회지 Vol.7 No.4

본 연구에서는 플라이애시를 치환한 시멘트 모르터의 양생온도에 따른 강도증진을 검토하기 위하여 등가재령방법에 의한 강도증진해석을 실시하였다. 플라이애시를 30% 치환한 시멘트모르터의 겉보기활성화에너지를 ASTM C 1074 방법에 의하여 산정한 결과 34.75KJ/mol로 산정되었고, 이를 토대로 Plowman 모델과 Gompertz 모델을 이용하여 해석한 결과 해석치가 측정치를 양호하게 추정함을 알 수 있었고 특히 Gompertz 모델식이 보다 양호한 추정 정밀도를 갖는 것으로 확인되었다. This paper is to present the strength estimation of the cement mortar incorporating 20% of fly ash by equivalent age method. ASTM C 1074 was applied to achieve apparent activation energy($E_a$). Cement mortar was cured at the temperature of $5^{\circ}C$, $20^{\circ}C$ and $35^{\circ}C$ respectively to measure the setting time and compressive strength at designed age. According to test results, it is found that an increase in curing temperature resulted in an acceleration of setting time. $E_a$ was achieved to 34.75 KJ/mol. It was also found that by estimating strength development with Plowman and Gompertz model, good agreement between calculated value and measured one was achieved.

이름도 얼굴도 모르는 북한 친구들에게

한민철 한국국어교육학회 1997 세계가 한동네 Vol.1997 No.-

Log-based Patient-specific Quality Assurance Process for Carbon-ion Raidation Therapy : A Prliminary Study

한민철,김창환,홍채선,박세준,김진성 대한방사선방어학회 2022 대한방사선방어학회 학술발표회 논문요약집 Vol.2022 No.04

고온조건이 고강도 콘크리트의 역학적 특성 및 미세구조에 미치는 영향

한민철,최현규,Han, Min-Cheol,Choi, Hyun-Kyu 대한건축학회 2011 대한건축학회논문집 Vol.27 No.3

Nowadays, the use of high strength concrete has been increased. However, its dense microstructure leads to spalling due to fire, which causes degradation and collapse of concrete structures. Various attempts regarding optimum solution for spalling prevention of high strength concrete are made continuously. In this paper, tests are carried out to clarify the effect of elevated temperature on mechanical behavior and microstructure of the high strength concrete incorporating 20% of fly ash and 10% of silica fume. 0.05% of nylon and polypropylene fiber was added to the concrete to prevent a spalling during test. Temperature was varied from $20^{\circ}C$ to $800^{\circ}C$, with the interval of $100^{\circ}C$. For the observation of microstructure of the concrete, SEM, MIP and XRD tests were conducted. According to results, An increase in temperature led to decrease of strength above $400^{\circ}C$ and ductile behaviour between strain and stress relationship was observed at above $400^{\circ}C$.

혼합시멘트를 사용한 콘크리트의 기온보정강도 산정 ( Determination of the Strength Compensation of Concrete Containing Blended Cement )

한민철,한천구 대한건축학회 2001 大韓建築學會論文集 : 構造系 Vol.17 No.2

등가재령 방법에 의한 혼화재 치환 고강도 시멘트 모르타르의 자기수축 해석에 관한 연구

한민철 한국건축시공학회 2014 한국건축시공학회지 Vol.14 No.1

본 연구에서는 양생온도변화에 따른 자기수축의 예측을 위하여 FA 및 SF를 치환한 시멘트모르타르를 대상으로 자기수축변화를 측정하고 이를 등가재령방법으로 해석하고자 하였다. 이를 위해 수화반응의 온도민감도를 고려하는 Ea의 변화에 따라 지수함수모델을 이용하여 자기수축 해석을 실시하였는데, 경화단계의 Ea를 이용할 경우 응결단계의 Ea를 사용한 경우보다 정확한 해석이 가능한 것으로 나타났는데, 이는 경화의 전단계에 걸친 수화의 온도민감도 영향을 반영한 Ea값에 기인된 결과로 사료된다. The objective of this study is to investigate an effect of curing temperature on autogenous shrinkage of highstrength cement mortar with 0.15 of W/B incorporating fly ash and silica fume in terms of equivalent age. Thecontents of fly ash and silica fume are varied from 10% to 30%. Non linear regression model applying equivalent agewas used to estimate the autogenous shrinkage evolution. To obtain apparent activation energy(Ea), setting timemethod by Pinto and existing method were calculated and compared respectively. Test results showed that use of silicafume increased autogenous shrinkage while use of fly ash decreased it. It was also found that poor agreements wereobtained when Ea by setting time was applied. But, application of existing Ea resulted in a good agreement betweencalculated autogenous shrinkage and measured one.

등가재령 방법에 의한 고온조건하 플라이애시 사용 콘크리트의 압축강도 증진 해석

한민철 대한건축학회 2007 大韓建築學會論文集 : 構造系 Vol.23 No.3

In this paper, estimation of compressive strength of concrete incorporating fly ash subjected to high temperature was investigated. Ordinary Portland cement and fly ash cement(30% of fly ash) were used, respectively. Water to binder ratios ranging from 30% to 60% and curing temperatures ranging from 20℃∼65℃ were also adopted for experimental parameters. According to results, at high temperature, FAC had higher strength development at early age than OPC concrete and it kept its high strength development at later age due to accelerated pozzolanic reaction subjected to high temperature. For strength estimation, Carino model based on equivalent age were applied to verify the availability of estimation model. It shows that fair agreements between calculated values and measured values were obtained evaluating compressive strength with Carino curve. The application of Carino model at high temperature had remarkable deviations at later equivalent age. For this reason, introduction of correlation parameter into Carino model considering the influence of age factor was done in this paper. Corrected estimation model showed good agreements between calculated values and measured ones regardless of type of cement and W/B. However, correction factors in terms of equivalent age should be considered to enhance the accuracy of long term strength estimation of concrete at high curing temperature.

단열소재 종류 및 조합에 따른 외벽단열 패널용 시멘트 복합체의 공학적 특성

한민철,조병영,이건철,노상균,전규남 한국건축시공학회 2011 한국건축시공학회지 Vol.11 No.2

본 연구에서는 단열소재 종류 및 조합의 치환률 변화에따른 외벽단열패널의 공학적 특성에 대하여 분석하였는데,그 결과 굳지않은 모르터의 플로우의 경우 단열소재 치환률이 증가할수록 급격히 저하되는 결과를 나타내었으며, 공기량의 경우 단열소재 치환률이 증가될수록 점차 증가되는 결과를 나타내었다. 경화 모르터의 휨강도의 경우 단열소재치환률이 증가될수록 전반적으로 플레인에 비해 점차 강도가 저하되는 경향을 나타내었으나 PL 2% 치환 시 증가되는결과를 나타내었다. 열전도율의 경우 단열소재 치환률이 증가될수록 급격히 낮아지는 경향을 나타내었으며, 단위용적질량과 열전도율의 상관관계의 경우 단위용적질량이 감소할수록 열전도율은 우수한 결과를 나타내었다. 단열소재 종류및 조합에 따른 휨강도의 경우 전반적으로 플레인과 유사한강도값을 나타내었으나 V+CB+PL을 3% 치환한 조합의 경우 모르터 내부가 밀실해짐에 따라 강도값이 증가되는 결과를 나타내어 단열소재 종류 및 조합 가운데 가장 우수한 결과를 도출할 수 있었다. In this study, the engineering characteristics of outer wall insulation panels according to type of insulation materials, their combination, and the contents of insulation materials were tested. Vermiculate, ceramic bead, perlite and expanded polystyrene were used as insulation materials. Flexural strength and thermal conductivity depending on the insulation materials used were measured. It was found that the flow of fresh mortar significantly decreased with an increase in the contents of insulation materials. In terms of the effect of insulation materials on thermal conductivity, an increase in insulation materials resulted in a decrease of thermal conductivity. In particular, PL and EPS, when used together, have lower thermal conductivity than other materials. Regarding the flexural strength of the hardened mortar, the strength showed a tendency to gradually decrease according to the increase in contents of insulation materials, compared to that of the plain mortar. In terms of the flexural strength depending on various types of insulation materials and its combination, it was found that the flexural strength of cement mortar containing 3% of vermiculate(V)+ceramic bead(CB)+perlite(PL) was the highest among the specimens tested.

양생온도가 초지연제 콘크리트의 강도발현에 미치는 영향

한민철 청주대학교 산업과학연구소 2023 産業科學硏究 Vol.41 No.1

This study is to investigate the effect of curing temperatures on the strength development of the super retarding concrete and to present the prediction of strength development applying equivalent age method. Sugar based super retarding agent (SRA)is used to delay the setting time of the concrete in order to achieve integration performance between joints and to reduce hydration heat of mass concrete. Dosages of SRA are varied from 0% to 0.3%. The concrete incorporating 15% of fly ash and 30% of blast furnace slag with 45% and 55% of water to binder ratio (W/B) are fabricated and cured at 5, 20 and 35 ℃ until designed ages. To estimate the strength development of SRA concrete, equivalent age method reflecting apparent activation energy at setting stage(Ea) is applied. Test results indicated that the increase of SRA resulted in a delay of setting time and Ea is calculated from 20~30 kJ/mol at initial set and 30~40 kJ/mol at final set. Plowman model is applied to simulate the strength development with equivalent age and has good agreement with measured values.