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양생직후 초기재령의 콘크리트 내부 온도와 상대습도의 측정 및 분석
박철우(Park Cheolwoo),박영훈(Park Young-Hoon),박용걸(Park Yong-Gul) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-
Concrete is still one most common construction materials even in railway structures. As structures become massive and mega-sized, the importance of early age concrete quality control becomes more significant. Among various factors, relative humidity and temperature are the primary factors governing the early age quality. Temperature raise due to cement hydration causes stress, which can develop to cracking with internal and/or external restraints. Exposure conditions including ambient temperature, humidity and wind also significantly affect the cracking behavior of early age concrete. Among many of studies on the early age concrete behavior, investigation on the variation of temperature and relative humidity internal of concrete is not common. That is in part because the difficulties in measuring the relative humidity and temperature inside the concrete. This study used a digital sensor with an appropriate logger to measure internal temperature and relative humidity. This direct measuring method is expected to provide more reliable and comprehensive data acquisition on the early age behavior of concrete.
박철우 ( Park Cheolwoo ),권승준 ( Kwon Seungzoon ),이학용 ( Lee Hackyong ),장태연 ( Jang Taeyeon ),최우현 ( Choi Woohyun ) 한국구조물진단유지관리공학회 2009 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.13 No.2
Pozzolanic materials are often incorporated into the concrete to improve strength and durability of concrete. These include fly ash, silica fume, ground granulated blast furnace slag (GGBFS), and other calcined natural pozzolanic materials such as rice husk ash and metakaolin. The use of pozzolanic materials induces significantly improved durability and strength development by converting the calcium hydroxide (CH) into calcium silicate hydrate (C-S-H). Rice husk ash, produced by controlled burning of the rice husk, is a very reactive pozzolanic material which is comparable to the silica fume. This study investigates the strength development of rice husk ash incorporated concrete. Experimental variables included w/c ratio of 0.38 and 0.45 and addition of silica fume and rice husk ash. Each mineral admixture replaced the cement content by 5% and 10%.
산업부산물(플라이애시)과 실리카퓸을 재활용한 숏크리트의 환경유해성 평가
박철우(Park Cheolwoo),심종성(Sim Jongsung),강태성(Kang Taesung),박성은(Park Seongeun) 대한토목학회 2010 대한토목학회논문집 C Vol.30 No.3
최근 산업발전에 따른 천연자원 고갈, 공해물질 배출, 폐기물 발생 등과 같은 부가적인 문제는 세계적으로 이슈화되고 있다. 현재 국내 산업부산물은 연간 600만 톤이 발생하며, 매립, 소각, 저장과 같은 1차원적인 처리에도 한계가 발생하고 있는 실정이다. 본 연구에서는 산업폐기물인 플라이애시 재활용 연구의 일환으로 플라이애시와 실리카퓸을 숏크리트에 활용하여 자원의 재활용 문제뿐만 아니라 숏크리트에 적용함으로써 플라이애시의 사용을 확대하고자 한다. 그러나 숏크리트에 적용하기에 앞서 최근 범지구적으로 이슈화되고 있는 환경문제에 보다 적극적으로 대처하기 위하여 환경유해성 평가가 반드시 필요하며, 본 연구에서는 예비 배합 및 압축강도 시험을 통해 도출한 10가지 배합에 대하여 화학성분 분석시험과 중금속 용출시험을 통해 환경 영향평가를 실시하였다. 압축강도 시험결과, 모든 배합에서 국내외 기준을 만족하는 것으로 나타났으며, 중금속 용출시험의 경우 Cr, Cd, Hg 성분은 검출되지 않고 Pb 성분은 플라이애시가 함유된 일부분의 경우에서만 검출되었다. 그리고 Cu, As 성분이 모든 배합에서 검출되었으나 국내외 기준에 모두 만족하는 결과를 얻을 수 있었다. The problems such as natural resource exhaustion, pollutant emission and waste generation are increasing worldwide with the industrial development. The quantity of the industrial by-product in Korea is 6 million tons a year, and even its basic treatment processes including landfill, incineration and storage have reached their limits. In this study, fly ash and silica fume were applied to shotcrete to develop a method for the reuse of resources and to increase the use of fly ash, which is an industrial waste. An environmental hazard evaluation is a must to actively address the worldwide environmental problems, though. Therefore, an environmental impact assessment was conducted using the chemical content analysis test and heavy metal exudation test, for ten mixtures that were obtained through the pre-mixing and compressive strength tests. The results of the compressive strength test showed that all mixtures satisfied national and international standards. Cr, Cd and Hg were not detected, and Pb was detected only in some cases with fly ash. Cu and As were detected in all mixtures, but all of them satisfied national and international standards.