단열갱폼을 활용한 한중콘크리트 시공의 현장적용에 관한 기초적 연구

남경용,하정수,정상진 단국대 부설 리모델링연구소 2011 리모델링 연구소 논문집 Vol.9 No.2

This study is analyzing a member kind after placing concrete, the location-based temperature record, and the strength development, by making insulation gang-form with application of polyurethane form to general gang-form for securing efficient concrete quality in the condition of cold weather. According to our experimental results, the member of general gang-form with curing in the same condition as the actual field didn’t drop to under 3˚C until before 24 hours in the early part, but fell to under 0˚c from 36 hours later because a large rise in temperature caused by hydration reaction didn't occur. On the other hand, in case of insulation gang-form, the temperature on the surface and the central part didn't go down to under 3˚C before 12 hours in the early part and didn't fall to under it even until 72 hours after it while the peak temperature went up to 12˚C. Thus, it could be known to definitely have excellent insulation effect compared to space heating curing, which is generally performed on the spot. In comparison with space heating curing whose error in curing temperature is big every field, it is judged to likely have great effect on improvement in concrete quality given the work construction in cold weather and on early demolding in a cast during winter.

경질우레탄 보드를 접착한 갱폼 사용에 따른 콘크리트의 온도이력 및 강도발현 특성

남경용,하정수,정상진 단국대 부설 리모델링연구소 2012 리모델링 연구소 논문집 Vol.10 No.2

This paper has fabricated insulation gang-form adhering general gang-form to the polyisocyanurate board and analyzed type of members, temperature record by locations and strength development after placing the concrete, in order to ensure efficient concrete quality under cold weather. According to our test, we can see that general gang-form member with curing under the same conditions as the actual field has a trend of constantly decreasing concrete temperature regardless to surface or central area due to rapid outdoor air temperature reduction, while in the case of insulation gang-from I and II, temperature increased up to around 25℃ after 12 hours under rapid outdoor air temperature change and temperature distribution did not appear large separation according to hydration reaction measurement locations. In addition, results of measurement for temperature records on weak insulation area by types of gang-forms showed that the temperature record distribution on the form tie surface and horizontal bar surface of angle bar has generally similar trend as the temperature records on the surface of the insulation gang-form, while corner area of the insulation gang-form did not have large insulation effect. It is determined that it requires additional curing measure for the weak corner area of the insulation gang-form in the future.

Rock Test Hammer를 사용한 초고강도 콘크리트 강도추정에 관한 기초적 연구

남경용,김성덕,최석,이영도 한국건축시공학회 2019 한국건축시공학회지 Vol.19 No.3

This study examines the estimation of strength through a ultra-high strength concrete mock-up specimen using the rock compressive strength test hammer. According to the test result, the commonly used strength estimation formulae showed differences among them when the data of this test were applied. In additional, it show that these formulae underestimated the actual measurements further when the compressive strength was 30MPa or greater and deviated the distribution range of actual measurements in all strength ranges. The rock test hammer showed a higher correlation than type N Schmidt hammer regardless of the direction of hit for each type of W/B and the inclusion of coarse aggregate, and mortar showed a little higher correlation than concrete. As a result, it can be suggested that the coefficient of variation and the standard deviation of the mortar(2.26%/1.36) are lower than those of the concrete(4.06%/2.5), and the smaller the size of the coarse aggregate, the smaller the coefficient of variation and the more accurate the value. 본 논문은 암반용 압축강도테스트 해머를 이용하여 초고강도 콘크리트 모의부재 압축강도 실험을 통한 강도추정에 대해서 검토하고자 하였다. 실험결과에 따르면, 본 실험 데이터값을 토대로 기존에 주로 사용되던 강도 추정식을 적용할 경우 각 식마다 차이가 있는 것으로 나타났다. 또한 압축강도 30MPa 이상으로 갈수록 실측 데이터를 과소평가하고 있는 것으로 나타났으며, 모든 강도 영역에서 실측치의 분포범위를 크게 벗어나고 있는 것으로 나타났다. W/B 종류별 타격방향 및 굵은 골재 유무와 상관없이 암반용 테스트 해머가 N형 슈미트 해머보다 높은 상관관계를 나타내었으며, 모르타르가 콘크리트보다 좀 더 높은 상관관계를 나타내었다. 그리고 굵은 골재 유·무에 따른 모의부재 반발도 측정결과 모르타르(2.26%/1.36)의 변동계수와 표준편차가 콘크리트(4.06%/2.5)보다 낮게 나타났으며, 굵은 골재의 치수가 작을수록 변동계수가 작아져 보다 정확한 값을 나타내는 것을 알 수 있다.

경질우레탄 보드를 접착한 갱폼 사용에 따른 콘크리트의 온도이력 및 강도발현 특성

남경용(Nam, Kyung-Yong),원준연(Won, Joon-Yuen),전재열(Chun, Jae-Youl),정상진(Jung, Sang-Jin) 대한건축학회 2012 大韓建築學會論文集 : 構造系 Vol.28 No.7

This paper has fabricated insulation gang-form adhering general gang-form to the polyisocyanurate board and analyzed type of members, temperature record by locations and strength development after placing the concrete, in order to ensure efficient concrete quality under cold weather. According to our test, we can see that general gang-form member with curing under the same conditions as the actual field has a trend of constantly decreasing concrete temperature regardless to surface or central area due to rapid outdoor air temperature reduction, while in the case of insulation gang-from I and II, temperature increased up to around 25℃ after 12 hours under rapid outdoor air temperature change and temperature distribution did not appear large separation according to hydration reaction measurement locations. In addition, results of measurement for temperature records on weak insulation area by types of gang-forms showed that the temperature record distribution on the form tie surface and horizontal bar surface of angle bar has generally similar trend as the temperature records on the surface of the insulation gang-form, while corner area of the insulation gang-form did not have large insulation effect. It is determined that it requires additional curing measure for the weak corner area of the insulation gang-form in the future.

-20℃ 혹한기 조건에서 단열갱폼 사용에 따른 콘크리트 온도이력 및 미세공극 특성

남경용(Nam, Kyung-Yong),하정수(Ha, Jung-Soo),이동하(Lee, Dong-Ha),박태원(Park, Tae-Won),원준연(Won, Joon-Yuen) 대한건축학회 2016 大韓建築學會論文集 : 構造系 Vol.32 No.1

This paper is about a test performed to concrete form work in -20℃ cold weather conditions on climate change by global warming Furthermore, this paper examines limitations in application insulation gang form and analysis temperature history, strength development and characteristic of micropore of concrete placed in abnormal winter weather. According to the test result, concrete temperature dropped below 0℃ in the case of general gang form 12 hours after concrete placement. However, we could find excellent insulating effect rather than general gang form in the case of insulation gang form because temperature of outer surface and core of concrete has not dropped below 7℃ and highest temperatures was recorded 8~10℃ within 12 hours despite drastic ambient temperature conditions after concrete placing. In comparison of temperature record of surface portion of insulation gang form and that with or without wales by temperature record of insulation weak point, with wales is not as good as that on surface portion of insulation gang form. The reason for this is thought to be the decline in hydration reaction of concrete due to the decreases of ambient temperature and lack of insulation effect by wale protection made of pvc. As concrete got aged, the number of micropores less than 1㎛ has increased and it of the large voids has decreased. Also, more small pore were observed in concrete placed with insulation gang form than with general gang form.

단열갱폼을 활용한 한중콘크리트 시공의 현장적용에 관한 기초적 연구

남경용(Nam, Kyung-Yong),하정수(Ha, Jung-Soo),원준연(Won, Joon-Yuen),백민수(Paik, Min-su),임남기(Lim, Nam-Gi),정상진(Jung, Sang-Jin) 대한건축학회 2011 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.31 No.1(구조계)

경질우레탄 보드를 접착한 갱폼 사용에 따른 콘크리트 온도이력특성

남경용(Nam, Kyung Yong),여상길(Yu, Sang Gil),하정수(Ha, Jung Soo),원준연(Won, Joon Yuen),전판근(Jeon, Pan Keun),정상진(Jung, Sang Jin) 한국콘크리트학회 2012 한국콘크리트학회 학술대회 논문집 Vol.2012 No.5

합성수지 거푸집의 휨 성능평가 및 강성모델 제시

남경용(Nam, Kyung-Yong),이혜진(Lee, Hye-Jin),양근혁(Yang, Keun-Hyeok),문주현(Mun, Ju-Hyun) 대한건축학회 2020 대한건축학회논문집 Vol.36 No.8

The objective of this study is to examine the flexural behavior of the developed synthetic resin formwork and propose a simple model for their stiffness (K) for straightforwardly determining a thickness of form to achieve the minimum requirements specified in KS F 5651. The deflection of the synthetic resin formworks was commonly greater than that of the euro form, indicating a lower flexural stiffness for the former than the latter. As a result, all synthetic resin formwork tested did not meet the deflection requirement of KS F 5651. The stiffness model was derived from strain compatibility, force equilibrium, and curvature distributions along the form length on the basis of the elasticity theorem, considering the tie-holes given in the form. The proposed model predicts accurately the slope of the load-displacement curve obtained from the foams under flexure. Using the proposed K model, design chart is developed for determining the thickness of formwork with different sizes and material properties.

-20℃ 양생조건에서 단열갱폼 사용에 따른 콘크리트 온도이력특성

남경용(Nam, Kyung Yong),하정수(Ha, Jung Soo),조한병(Cho, Han Byung),원준연(Won, Joon Yuen),정상진(Jung, Sang Jin) 한국콘크리트학회 2014 한국콘크리트학회 학술대회 논문집 Vol.2014 No.5

합성수지 거푸집의 전과정 환경영향평가에 관한 연구

남경용 ( Nam Kyung-yong ),양근혁 ( Yang Keun-hyeok ),이영도 ( Lee Young-do ) 한국건축시공학회 2020 한국건축시공학회지 Vol.20 No.3

합성수지 거푸집은 내부식성이 우수한 경량의 고밀도 폴리에틸렌(HDPE)를 재료로 사용한다. 합성수지 거푸집의 전과정 평가를 위하여 ISO FDIS 13352에서 요구하는 시스템 경계를 만족하도록 공정 흐름도를 고려하였다. 이에 따라 고려된 시스템 경계는 Cradle-to- Product shipmen이다. 고려된 시스템 경계에서 투입 에너지원, 사용재료, 운송수단, 제작공정 등으로부터 산정한 전과정 목록(LCI) 데이터베이스를 분석하였다. 합성수지 거푸집의 LCI 데이터 분석으로부터 환경부의 환경영향평가지수 방법론에 기반하여 분류화, 정규화, 특성화 및 가중치 과정을 거쳐 환경영향평가를 수행하고, 그 결과는 유로폼의 환경영향 평가값과 비교하였다. 실험결과, 전용횟수를 고려한 CO₂ 배출량은 유로폼 대비 2배 이상의 전용성을 갖는 합성수지 거푸집이 약 32 % 가량 낮았다. 이는 합성수지 거푸집 사용은 유로폼 대비 자재 생산을 1/2로 줄일 수 있으며, CO₂ 배출량 저감으로 이어질 수 있다. Synthetic resin formwork is made of lightweight high-density polyethylene(HDPE). This study used a process flow chart that satisfies the system boundary (such as Cradle-to- Product shipmen ) required by ISO FDIS 13352 to evaluate the entire process of synthetic resin foam using. The entire life cycle inventory (LCI) database calculated from input energy sources, materials used, transportation methods, and manufacturing processes at the system boundary was analyzed. Based on the environmental impact assessment index methodology of the Ministry of Environment from the LCI data analysis of synthetic resin formwork, the environmental impact assessment was carried out through classification, normalization, characterization, and weighting process. The experimental results are as follows the amount of CO₂ (carbon) emission considering the number of conversions was about 32% lower than that of the Euroform. This shows that the use of synthetic resin formwork reduces material production by half compared to Euroform and reduces CO₂ (carbon) emissions.