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재생골재 생산방식의 차이에 따른 재생 굵은골재의 품질 특성에 관한 비교 연구
심종우,이문환,이세현,전현규 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1(구조계)
The purpose of this study is intended for effective recycling of waste concrete. It analyzes the quality 0 the recycled coarse aggregate with production types. The conclusions of the study are as follows. 1. The recycled coarse aggregate which is produced through 5th Crushing Process (A-Type) shows the improvement in grading and particle shape, reduction in an absorption rate until 1.14% due to removal of attached the mortar and paste. Therefore, it satisfies the standards of KS F 2573(recycled aggregate for concrete) as the first grade. 2. The recycled coarse aggregate which is produced through 3rd Crushing Process(B-Type) is suited to the quality prOVlSlOns of the standards of KS F 2573, shows a 3.12% absorption rate that is second grade as recycled coarse aggregate. Based on the above results, it is possible to product first and second grade recycled coarse aggregates with production types. It is concluded that recycled coarse aggregate with production types can be used as aggregate within required conditions. And more researches are also needed to make recycled coarse aggregate better to use for concrete.
시각 장애인의 예방적 건강검진, 건강행태와 정신 건강에 대한 분석
심종우,한승한,Jong Woo Shim,Seung Han Han 대한안과학회 2012 대한안과학회지 Vol.53 No.12
Purpose: To better understand visual disabilities via preventative health examination, health behavior, and psychological health. Methods: The preventative health examination, health behavior, and psychological health records of 4,724 participants over the age of 40 who completed the third Korean National Health and Nutrition Examination Survey (KNHANES III) were analyzed. The participants were divided into 3 groups for analysis: subjects without disabilities, subjects with disabilities but without visual disabilities, and subjects with visual disabilities. The unadjusted mean and the adjusted mean for which socioeconomic factors were adjusted were calculated. Results: In the preventative health examination there were no differences between the 3 groups except for a statistically significant increase in the number of cholesterol check-ups in the visual disability group. In the health-related behavior analysis, lifetime smoking and routine physical activity were similar between the visual disability and no disability group, however, these factors were greater in the disability without visual disability group. The analysis of psychological health revealed that major depressive symptoms, suicidal ideation, suicidal attempts and psychological consultations were greater in the disability without visual disability and the visual disability groups compared to the participants without disability. However the overall number of psychological consultations was low. Conclusions: There was no difference in the frequency of preventative health examinations between each group. However, there was an increase in the prevalence of psychological problems in subjects with visual disabilities compared to subjects without disabilities and subjects with disabilities but without visual disabilities. Thus, ophthalmologists should consider psychological aspects when dealing with patients with visual disturbances.
고로슬래그를 사용한 습식 순환 잔골재 모르타르의 강도 특성에 관한 연구
심종우 한국구조물진단유지관리공학회 2010 한국구조물진단유지관리공학회 논문집 Vol.14 No.5
고로슬래그 미분말을 순환골재 모르타르 및 콘크리트의 제조에 활용할 경우, 순환골재에서 용출된 Ca(OH)2가 고로슬래그에 대한 자극제 역할을 수행하여 수화반응을 개선할 수 있을 것으로 판단되고 고로슬래그를 통해 알칼리 저감 효과를 얻을 것으로 예상되어 본 연구를 진행하게 되었다. 그 결과 고로슬래그 미분말을 혼입․사용한 순환 잔골재 모르타르는 재령 3일에서는 고로슬래그 혼입율에 따라 강도가 감소하는 결과를 나타냈다. 이는 고로슬래그의 수화반응이 일어나지 않았기 때문으로 판단되며 또한, 순환 잔골재 혼입률에 관계없이 고로슬래그 미분말의 혼입률이 증가함에 따라 재령 3일 측정한 수화활성도도 저하되는 것으로 나타났다. 재령 7일에서는 순환 잔골재에서 용출된 수산화칼슘(Ca(OH)2)이 자극제 역할을 수행하여 고로슬래그 미분말을 혼입한 배합의 압축강도 발현이 천연 잔골재를 사용한 모르타르보다 서서히 증가하는 결과를 보이기 시작하였으며 이로 인해 재령 7일 측정한 고로슬래그 미분말을 단계별로 혼입한 배합의 수화활성도가 고로슬래그를 혼입하지 않은 배합보다 높아지는 것으로 나타났다. 재령 28일에서는 고로슬래그 미분말 혼입률 30% 배합에서는 고로슬래그의 수화반응으로 인해 천연 잔골재를 사용한 배합보다 높은 압축강도를 보이기 시작하였으며 이때 측정한 수화활성도는 천연 잔골재를 사용한 배합과 특별한 차이를 보이지 않았으며, 이는 지속적으로 수산화칼슘(Ca(OH)2)이 공급되지 못하였기 때문으로 판단된다. This study aims to obtain technical data for improvement of utilization of Blast Furnace Slag(BFS), recycled aggregate in the future by complementing fundamental problems of BFS such as manifestation of initial strength and excessive alkali quantity as well as weakness of recycled fine aggregate through manufacturing of recycled fine aggregate mortar using BFS. The recycled aggregate includes the cement paste hardened as the surface and the type of the aggregate, which contains plenty of calcium hydroxide(Ca(OH)2) as well as the unhydrated cement. Accordingly, the objectives of this study are to inspect the manufacturing the recycled fine aggregate mortar used with blast furnace slag, to consider the effects of the recycled aggregate on the strength development of ground granulated blast furnace slag, and then to acquire the technical data to take into consideration the further usages of the recycled aggregate and blast furnace slag. In eluted ions from recycled aggregate, it showed that there were natrium(Na+) and kalium(K+), expected to be flown out of unhydrated cement, as well as calcium hydroxide(Ca(OH)2). Application of this water to mix cement mortar with ground granulated blast furnace slag was observed to expedite hydration as calcium hydroxide(Ca(OH)2) and unhydrated cement component were expressed to give stimuli effects on ground granulated blast furnace slag. The results of the experiment show that the recycled aggregate mixed with blast furnace slag has comparatively higher hydration activity in 7 day than the mortar not mixed with one in 3 day mortar does, causing the calcium hydroxide in the recycled fine aggregate to work on as a stimulus to the hydration of ground granulated blast furnace slag.
습식 생산된 재생 잔골재를 사용한 콘크리트의 특성에 관한 연구
심종우(Shim Jong-Woo),유명열(Yu Myoung-Youl),이세현(Lee Sea-Hyun) 대한건축학회 2004 大韓建築學會論文集 : 構造系 Vol.20 No.12
The recycled fine aggregate produced by a existing method is not recommended to use recycled fine aggregate for production of quality concrete, considering that it increases the water demand of fresh concrete and lower the strength and probably the durability of hardened concrete. But, the recycled fine aggregate is becoming increasingly important for alternative of natural fine aggregate faced shortage. Therefore, in this study, I proposed a production method which are able to produce recycled fine aggregates for quality concrete with a classifier, and analyzed the quality of the recycled fine aggregate and comprehended the properties of recycled aggregates mortar using the recycled fine aggregate to review whether it can be put to practical use for concrete. In the experiment, recycled fine aggregate is substituted for natural fine aggregate the rate of 0, 25, 50, 75 and 100% each. The results of the study are as follows.<br/> 1) The air content is increased irregularly according to the increasing of substitutive ratio<br/> 2) The slump and loss of slump with time since mixing are decreased irregularly according to the increasing of substitutive ratio<br/> 3) The compressive strength of the mortar using the recycled fine aggregate tends to be increase until 25~50% substitution ratio, and than reduced with the increase of the mixing ratio of recycled fine aggregate<br/> Based on the above results, it is concluded that the recycled fine aggregate through the wet production process can be used as fine aggregate on condition that the substitution ration is under 50%.