광물질 혼화재의 분산성 향상을 위한 프리믹스 시멘트의 유동성 실험

한천구,이해일,노상균,김기훈,Han, Cheon-Goo,Lee, Hai-Ill,Noh, Sang-Kyun,Kim, Ki-Hoon 한국건설순환자원학회 2009 한국건설순환자원학회지 Vol.4 No.2

최근 도심부의 건축구조물이 점차 고층화함에 따라 고강도 콘크리트에 대한 요구가 증가하고 있다. 특히 100 MPa 이상의 초고강도 콘크리트에는 산업부산물로서 강도증진 등의 목적에 사용되는 SF와 공사비 절감 및 장기강도증진 등의 목적에 사용되는 FA 및 BS 등 광물질 혼화재의 분상성과 관련한 유동성 검토가 매우 중요하다. 즉, 각각의 혼화재들이 가진 고결현상으로 인하여 분산성이 크게 저하되어 유동성을 저감시키는 문제가 발생한다. 따라서 본 연구에서는 이를 개선시키기 위해 프리믹스 시멘트의 효과를 분석하기 위하여 시멘트 페이스트의 유동성 실험을 하였는데, 그 결과를 요약하면 다음과 같다. 먼저 결합재 종류에 따라서는 OFS의 경우보다 OBS의 경우가 유동성이 증가하였는데, 이는 OBS의 경우는 BS의 유리질 표면에 의해 유동성이 증가하고, OFS의 경우는 FA의 혼화제 흡착작용에 의한 점성이 증가하여 유동성이 감소하였다. 혼합방법에 따라서는 개별혼합의 경우보다 프리믹스의 경우가 유동성이 증가하였는데, 이는 개별혼합의 경우는 페이스트 혼합 시 각각의 결합재가 균일하게 분산되기 어렵기 때문에 유동성이 나쁘게 나타난 반면, 프리믹스의 경우는 분산성이 증가하여 상대적으로 유동성이 양호하게 나타났다. 또한 믹싱시간은 30, 60, 180초로 길어질수록 결합재의 분산성이 좋아지고, SP제가 페이스트 입자 사이에 균등하게 분포되어 유동성이 증가하였다. The high rising building construction makes increasing the requirement of high strength concrete. Especially, the workability analysis is related with dispersion of admixture such as SF for improving strength and FA, BS for reducing construction cost and improving durability of Ultra High Strength Concrete which has over 100 MPa of compressive strength is very important. Precisely, decreases dispersion because of lumping situation of each admixture and it causes the workability of admixture is decreased. Therefore, the workability of cement paste is tested for analyze effects of pre-mixed cement for solving those problems with it to this research. The summary of the results are like below. First of all, OBS is increasing workability more than OFS. This result causes that the glassy surface of BS in the OBS is increasing workability and the absorption of admixture of FA in the OFS is decreasing workability. In the case of mixing methods, pre-mixing method is increasing workability more than normal one. This result shows that the normal mixing method is bad dispersion of binders. The other side, the pre-mixing method is good. Furthermore, depending on the mixing time, according to the increasing mixing time such as 30, 60, and 120 seconds, the dispersion of binders and workability turns better.

결합재 조합 및 믹싱시간 변화에 따른 프리믹스 시멘트를 사용한 고성능시멘트 모르터의 기초적 특성 분석

김기훈(Kim Ki-Hoon),이주선(Lee Ju-Sun),노상균(Noh Sang-Kyun),이해일(Lee Hai-Ill),황인성(Hwang Yin-Seong),한천구(Han Cheon-Goo) 대한건축학회 2008 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.28 No.1(구조계)

To verify the effect of pre-mix cement of the binder for ultra-high strength, this study imvestigated the kinds of binder, pre-mix cement or not and the basic characteristics of mortar with the changes of mixing hours as a variable and the results are summarized as followings. From the characteristic of fresh mortar, mixing time could be known to be fast when admixture is used rather than OPC, especially at blast furnace slag powder rather than fly ash and when pre-mixed rather than mixed, respectively. Ring flow and flow cone flow of mortar were appeared as the largest regardless of mixing time and, regarding to the change of the kind of binder, it was appeared to be large in case that blast furnace slag powder is used rather than fly ash, when pre-mixed rathe than mixed, respectively and as the mixing time became longer. The compressive strength of hardened mortar, in case of admixture is used rather than OPC, was low at the initial aging like 3 days but was rather appeared to be high at 28 days and was excellent in case that fly ash rather than blast furnace slag powder was used as the binder, when pre-mixed than mixed, respectively and as the mixing hours became longer like 180 seconds.

프리믹스 시멘트를 사용한 고강도 콘크리트의 압축강도 특성

김성일 ( Jin¸ Cheng-ri ),최성용 ( Choi¸ Sung-yong ),이해일 ( Lee¸ Hai-ill ),황인성 ( Hwang¸ Yin-seong ),김성수 ( Kim¸ Sung-su ),한천구 ( Han¸ Cheon-goo ) 한국구조물진단유지관리공학회 2008 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.12 No.1

This study analysis the properties of the high-strength concrete using pre-mixed cement corresponding the change of W/B suggesting table for trial mix, and the results are summarized as following. The amount of AE and high-range water reducing agent decreased as W/B increased. The time of set was delayed as changing the ratio of W/B except 20% of W/B. The compressive strength decreased as W/B increased, but the flow did not influenced by W/B. The regression formula of 28th day compressive strength by B/W deciding suitable for W/B when plan the design of mix proportion is like this, σ₂₈ = 38.1 +11.620 × B/W(R = 0.9685)

프리믹스 시멘트를 사용한 초고강도 콘크리트의 기초적 특성

한천구(Han Cheon-Goo),노상균(Noh Sang-Kyun),이해일(Lee Hai-Ill),황인성(Hwang Yin-Seong) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.10

As the demand of super tall buildings is increasing in downtown areas, the practical use of ultra high strenth concrete over 80 ㎫ tends to be also increasing. Therefore, the importance of using pre-mix cement becomes higher as the demend of admixtures, which improves the workability, durability and economic feasibility of ultra high strength concrete, is increasing. The introduction of the pre-mix cement would be useful to reduce the number of silos and mixing time and raise the efficiency of production. The existing cement mixer plants can produce it with the existing facilities and hold a economically dominant position in the industry. Silica fume, which is considered to be an essential material in ultra high strength concrete, consisting of ultra fine particles and tending to lump when mixing with concrete since its dispersibility is low, does not improve the concrete quality even though it is expensive. However, pre-mix cement shall increase the flowability, strength, and durability of concrete since ultra fine particle admixture such as silica fume is dispersed enough in binders. The study compares and analyzes the fundamental properties of pre-mix cement by changing the method of mixing, kind of binders and kind of silica fume in order to understand the influence of the pre-mixed cement on ultra high strength concrete. The study shows that produce pre-mix cement by mixing blast-furnace slag powder and silica fume B in OPC, and then apply it to ultra high strength concrete, flowability shall be improved, setting shall be speeded up, and strength shall be developed.

실리카퓸 종류변화에 따른 프리믹스시멘트 페이스트의 유동특성

황인성(Hwang Yin-Seong),金成日(Jin Cheng-Ri),최성용(Choi Sung-Yong),이해일(Lee Hai-Ill),김성수(Kim Sung-Su),한천구(Han Cheon-Goo) 대한건축학회 2007 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.27 No.1

This study is to investigate the properties of the fluidity of the cement paste due to various and premixing silica fumes, and the results are summarized as following. The flow time of the paste using OPC is fastest among the various factors. It is delayed when FA was mixed comparing to BS. For the effect of the silica fume type, it is presented by order of A, B, and C. The flow of the paste is showed as the opposite tendency of the flow time of the paste, and it is displayed by order of B, A, and C. The viscosity of the paste is pwportional to the flow time of the paste. When FA is used, the orders are C, B, and A. For the BS, they are C, A, and B. All tests are showed for the straight tendency with the ring flow. The Correlation coefficient(R) are -0.847, 0.982, 0.981, and -0.882, so it was analyzed that they have close relationship.

아황산가스가 집파리의 산란시기와 우화율에 미치는 영향

이해풍,이복임,최덕일 동국대학교 산업기술환경대학원 1994 산업기술논총 Vol.2 No.-

When Musca domestica L. was exposed to the different levels of SO_2(0.3, 0.4, 1.5 ppm) in an air pollutant fumigation chamber, in the case of 0.4 ppm exposed, their oviposition rate significantly decreased with the increasing exposure period at 0.4 ppm and their oviposition was also delayed. The number of pupae from the house fly exposed to SO_2 distinctly decreased when compared with control group and this trend was more pronounced at F_2 than at F_1 generation. The emergence of pupae from the cohorts exposed to SO_2 showed a distinctly decreasing trend with the increase in exposure period and in the concentration of SO_2.